draft-ietf-manet-dlep-19.txt   draft-ietf-manet-dlep-20.txt 
Mobile Ad hoc Networks Working Group S. Ratliff Mobile Ad hoc Networks Working Group S. Ratliff
Internet-Draft VT iDirect Internet-Draft VT iDirect
Intended status: Standards Track S. Jury Intended status: Standards Track B. Berry
Expires: August 21, 2016 Cisco Systems Expires: September 9, 2016
S. Jury
Cisco Systems
D. Satterwhite D. Satterwhite
Broadcom Broadcom
R. Taylor R. Taylor
Airbus Defence & Space Airbus Defence & Space
B. Berry March 8, 2016
February 18, 2016
Dynamic Link Exchange Protocol (DLEP) Dynamic Link Exchange Protocol (DLEP)
draft-ietf-manet-dlep-19 draft-ietf-manet-dlep-20
Abstract Abstract
When routing devices rely on modems to effect communications over When routing devices rely on modems to effect communications over
wireless links, they need timely and accurate knowledge of the wireless links, they need timely and accurate knowledge of the
characteristics of the link (speed, state, etc.) in order to make characteristics of the link (speed, state, etc.) in order to make
routing decisions. In mobile or other environments where these routing decisions. In mobile or other environments where these
characteristics change frequently, manual configurations or the characteristics change frequently, manual configurations or the
inference of state through routing or transport protocols does not inference of state through routing or transport protocols does not
allow the router to make the best decisions. A bidirectional, event- allow the router to make the best decisions. A bidirectional, event-
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 21, 2016. This Internet-Draft will expire on September 9, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 7 1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 7
2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 8 2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 7
2.1. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 9 2.1. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 9
3. Destinations . . . . . . . . . . . . . . . . . . . . . . . . 9 3. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1. Router-requested Destinations . . . . . . . . . . . . . . 10 4. DLEP Session Flow . . . . . . . . . . . . . . . . . . . . . . 10
4. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.1. Peer Discovery State . . . . . . . . . . . . . . . . . . 11
5. DLEP Session Flow . . . . . . . . . . . . . . . . . . . . . . 12 4.2. Session Initialization State . . . . . . . . . . . . . . 12
5.1. Peer Discovery State . . . . . . . . . . . . . . . . . . 13 4.3. In-Session State . . . . . . . . . . . . . . . . . . . . 12
5.2. Session Initialization State . . . . . . . . . . . . . . 14 4.3.1. Heartbeats . . . . . . . . . . . . . . . . . . . . . 13
5.3. In-Session State . . . . . . . . . . . . . . . . . . . . 15 4.4. Session Termination State . . . . . . . . . . . . . . . . 13
5.3.1. Heartbeats . . . . . . . . . . . . . . . . . . . . . 16 4.5. Session Reset state . . . . . . . . . . . . . . . . . . . 13
5.4. Session Termination State . . . . . . . . . . . . . . . . 16 4.5.1. Unexpected TCP connection termination . . . . . . . . 14
5.5. Session Reset state . . . . . . . . . . . . . . . . . . . 17 5. Transaction Model . . . . . . . . . . . . . . . . . . . . . . 14
5.5.1. Unexpected TCP connection termination . . . . . . . . 17 6. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 15
6. Transaction Model . . . . . . . . . . . . . . . . . . . . . . 17 6.1. Experiments . . . . . . . . . . . . . . . . . . . . . . . 15
7. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 18 7. Scalability . . . . . . . . . . . . . . . . . . . . . . . . . 16
7.1. Experiments . . . . . . . . . . . . . . . . . . . . . . . 19 8. DLEP Signal and Message Structure . . . . . . . . . . . . . . 16
8. Scalability . . . . . . . . . . . . . . . . . . . . . . . . . 19 8.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 17
9. DLEP Signal and Message Structure . . . . . . . . . . . . . . 19 8.2. DLEP Message Header . . . . . . . . . . . . . . . . . . . 17
9.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 20 8.3. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 18
9.2. DLEP Message Header . . . . . . . . . . . . . . . . . . . 21 9. DLEP Signals and Messages . . . . . . . . . . . . . . . . . . 18
9.3. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 21 9.1. General Processing Rules . . . . . . . . . . . . . . . . 20
10. DLEP Signals and Messages . . . . . . . . . . . . . . . . . . 22 9.2. Status code processing . . . . . . . . . . . . . . . . . 20
10.1. Peer Discovery Signal . . . . . . . . . . . . . . . . . 23 9.3. Peer Discovery Signal . . . . . . . . . . . . . . . . . . 21
10.2. Peer Offer Signal . . . . . . . . . . . . . . . . . . . 24 9.4. Peer Offer Signal . . . . . . . . . . . . . . . . . . . . 21
10.3. Session Initialization Message . . . . . . . . . . . . . 24 9.5. Session Initialization Message . . . . . . . . . . . . . 22
10.4. Session Initialization Response Message . . . . . . . . 25 9.6. Session Initialization Response Message . . . . . . . . . 23
10.5. Session Update Message . . . . . . . . . . . . . . . . . 27 9.7. Session Update Message . . . . . . . . . . . . . . . . . 24
10.6. Session Update Response Message . . . . . . . . . . . . 28 9.8. Session Update Response Message . . . . . . . . . . . . . 25
10.7. Session Termination Message . . . . . . . . . . . . . . 28 9.9. Session Termination Message . . . . . . . . . . . . . . . 26
10.8. Session Termination Response Message . . . . . . . . . . 29 9.10. Session Termination Response Message . . . . . . . . . . 26
10.9. Destination Up Message . . . . . . . . . . . . . . . . . 29 9.11. Destination Up Message . . . . . . . . . . . . . . . . . 26
10.10. Destination Up Response Message . . . . . . . . . . . . 30 9.12. Destination Up Response Message . . . . . . . . . . . . . 27
10.11. Destination Announce Message . . . . . . . . . . . . . . 31 9.13. Destination Announce Message . . . . . . . . . . . . . . 28
10.12. Destination Announce Response Message . . . . . . . . . 31 9.14. Destination Announce Response Message . . . . . . . . . . 29
10.13. Destination Down Message . . . . . . . . . . . . . . . . 33 9.15. Destination Down Message . . . . . . . . . . . . . . . . 30
10.14. Destination Down Response Message . . . . . . . . . . . 33 9.16. Destination Down Response Message . . . . . . . . . . . . 30
10.15. Destination Update Message . . . . . . . . . . . . . . . 34 9.17. Destination Update Message . . . . . . . . . . . . . . . 31
10.16. Heartbeat Message . . . . . . . . . . . . . . . . . . . 35 9.18. Link Characteristics Request Message . . . . . . . . . . 32
10.17. Link Characteristics Request Message . . . . . . . . . . 35 9.19. Link Characteristics Response Message . . . . . . . . . . 33
10.18. Link Characteristics Response Message . . . . . . . . . 36 9.20. Heartbeat Message . . . . . . . . . . . . . . . . . . . . 34
11. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 38 10. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 34
11.1. Status . . . . . . . . . . . . . . . . . . . . . . . . . 39 10.1. Status . . . . . . . . . . . . . . . . . . . . . . . . . 35
11.2. IPv4 Connection Point . . . . . . . . . . . . . . . . . 41 10.2. IPv4 Connection Point . . . . . . . . . . . . . . . . . 37
11.3. IPv6 Connection Point . . . . . . . . . . . . . . . . . 42 10.3. IPv6 Connection Point . . . . . . . . . . . . . . . . . 38
11.4. Peer Type . . . . . . . . . . . . . . . . . . . . . . . 43 10.4. Peer Type . . . . . . . . . . . . . . . . . . . . . . . 39
11.5. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 44 10.5. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 39
11.6. Extensions Supported . . . . . . . . . . . . . . . . . . 44 10.6. Extensions Supported . . . . . . . . . . . . . . . . . . 40
11.7. MAC Address . . . . . . . . . . . . . . . . . . . . . . 45 10.7. MAC Address . . . . . . . . . . . . . . . . . . . . . . 41
11.8. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 46 10.8. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 41
11.9. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 47 10.9. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 42
11.10. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 48 10.10. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 43
11.11. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 49 10.11. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 44
11.12. Maximum Data Rate (Receive) . . . . . . . . . . . . . . 50 10.12. Maximum Data Rate (Receive) . . . . . . . . . . . . . . 45
11.13. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 50 10.13. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 46
11.14. Current Data Rate (Receive) . . . . . . . . . . . . . . 51 10.14. Current Data Rate (Receive) . . . . . . . . . . . . . . 46
11.15. Current Data Rate (Transmit) . . . . . . . . . . . . . . 52 10.15. Current Data Rate (Transmit) . . . . . . . . . . . . . . 47
11.16. Latency . . . . . . . . . . . . . . . . . . . . . . . . 53 10.16. Latency . . . . . . . . . . . . . . . . . . . . . . . . 48
11.17. Resources (Receive) . . . . . . . . . . . . . . . . . . 53 10.17. Resources . . . . . . . . . . . . . . . . . . . . . . . 48
11.18. Resources (Transmit) . . . . . . . . . . . . . . . . . . 54 10.18. Relative Link Quality (Receive) . . . . . . . . . . . . 49
11.19. Relative Link Quality (Receive) . . . . . . . . . . . . 55 10.19. Relative Link Quality (Transmit) . . . . . . . . . . . . 50
11.20. Relative Link Quality (Transmit) . . . . . . . . . . . . 55 10.20. Maximum Transmission Unit (MTU) . . . . . . . . . . . . 50
11.21. Maximum Transmission Unit (MTU) . . . . . . . . . . . . 56 11. Security Considerations . . . . . . . . . . . . . . . . . . . 51
12. Security Considerations . . . . . . . . . . . . . . . . . . . 57 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 52
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 57 12.1. Registrations . . . . . . . . . . . . . . . . . . . . . 52
13.1. Registrations . . . . . . . . . . . . . . . . . . . . . 57 12.2. Signal Type Registration . . . . . . . . . . . . . . . . 53
13.2. Signal/Message Type Registration . . . . . . . . . . . . 58 12.3. Message Type Registration . . . . . . . . . . . . . . . 53
13.3. DLEP Data Item Registrations . . . . . . . . . . . . . . 58 12.4. DLEP Data Item Registrations . . . . . . . . . . . . . . 53
13.4. DLEP Status Code Registrations . . . . . . . . . . . . . 58 12.5. DLEP Status Code Registrations . . . . . . . . . . . . . 53
13.5. DLEP Extensions Registrations . . . . . . . . . . . . . 59 12.6. DLEP Extensions Registrations . . . . . . . . . . . . . 53
13.6. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 59 12.7. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 54
13.7. DLEP IPv4 Link-local Multicast Address . . . . . . . . . 59 12.8. DLEP IPv4 Link-local Multicast Address . . . . . . . . . 54
13.8. DLEP IPv6 Link-local Multicast Address . . . . . . . . . 59 12.9. DLEP IPv6 Link-local Multicast Address . . . . . . . . . 54
14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 59 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 54
15. References . . . . . . . . . . . . . . . . . . . . . . . . . 60 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 54
15.1. Normative References . . . . . . . . . . . . . . . . . . 60 14.1. Normative References . . . . . . . . . . . . . . . . . . 54
15.2. Informative References . . . . . . . . . . . . . . . . . 60 14.2. Informative References . . . . . . . . . . . . . . . . . 55
Appendix A. Discovery Signal Flows . . . . . . . . . . . . . . . 60 Appendix A. Discovery Signal Flows . . . . . . . . . . . . . . . 55
Appendix B. Peer Level Message Flows . . . . . . . . . . . . . . 61 Appendix B. Peer Level Message Flows . . . . . . . . . . . . . . 56
B.1. Session Initialization . . . . . . . . . . . . . . . . . 61 B.1. Session Initialization . . . . . . . . . . . . . . . . . 56
B.2. Session Initialization - Refused . . . . . . . . . . . . 62 B.2. Session Initialization - Refused . . . . . . . . . . . . 56
B.3. Router Changes IP Addresses . . . . . . . . . . . . . . . 62 B.3. Router Changes IP Addresses . . . . . . . . . . . . . . . 57
B.4. Modem Changes Session-wide Metrics . . . . . . . . . . . 62 B.4. Modem Changes Session-wide Metrics . . . . . . . . . . . 57
B.5. Router Terminates Session . . . . . . . . . . . . . . . . 63 B.5. Router Terminates Session . . . . . . . . . . . . . . . . 58
B.6. Modem Terminates Session . . . . . . . . . . . . . . . . 63 B.6. Modem Terminates Session . . . . . . . . . . . . . . . . 58
B.7. Session Heartbeats . . . . . . . . . . . . . . . . . . . 64 B.7. Session Heartbeats . . . . . . . . . . . . . . . . . . . 58
B.8. Router Detects a Heartbeat timeout . . . . . . . . . . . 65 B.8. Router Detects a Heartbeat timeout . . . . . . . . . . . 59
B.9. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 66 B.9. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 59
Appendix C. Destination Specific Message Flows . . . . . . . . . 66 Appendix C. Destination Specific Message Flows . . . . . . . . . 60
C.1. Common Destination Notification . . . . . . . . . . . . . 66 C.1. Common Destination Notification . . . . . . . . . . . . . 60
C.2. Multicast Destination Notification . . . . . . . . . . . 67 C.2. Multicast Destination Notification . . . . . . . . . . . 61
C.3. Link Characteristics Request . . . . . . . . . . . . . . 68 C.3. Link Characteristics Request . . . . . . . . . . . . . . 61
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 69 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 62
1. Introduction 1. Introduction
There exist today a collection of modem devices that control links of There exist today a collection of modem devices that control links of
variable datarate and quality. Examples of these types of links variable datarate and quality. Examples of these types of links
include line-of-sight (LOS) terrestrial radios, satellite terminals, include line-of-sight (LOS) terrestrial radios, satellite terminals,
and broadband modems. Fluctuations in speed and quality of these and broadband modems. Fluctuations in speed and quality of these
links can occur due to configuration, or on a moment-to-moment basis, links can occur due to configuration, or on a moment-to-moment basis,
due to physical phenomena like multipath interference, obstructions, due to physical phenomena like multipath interference, obstructions,
rain fade, etc. It is also quite possible that link quality and rain fade, etc. It is also quite possible that link quality and
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|-DLEP--| | Protocol | |-DLEP--| |-DLEP--| | Protocol | |-DLEP--|
| | | (e.g. | | | | | | (e.g. | | |
| | | 802.11) | | | | | | 802.11) | | |
Figure 1: DLEP Network Figure 1: DLEP Network
In Figure 1, when the local modem detects the presence of a remote In Figure 1, when the local modem detects the presence of a remote
node, it (the local modem) sends a message to its router via the DLEP node, it (the local modem) sends a message to its router via the DLEP
protocol. The message consists of an indication of what change has protocol. The message consists of an indication of what change has
occurred on the link (e.g., presence of a remote node detected), occurred on the link (e.g., presence of a remote node detected),
along with a collection of DLEP-defined Data Items that further along with a collection of DLEP-defined data items that further
describe the change. Upon receipt of the message, the local router describe the change. Upon receipt of the message, the local router
may take whatever action it deems appropriate, such as initiating may take whatever action it deems appropriate, such as initiating
discovery protocols, and/or issuing HELLO messages to converge the discovery protocols, and/or issuing HELLO messages to converge the
network. On a continuing, as-needed basis, the modem devices use network. On a continuing, as-needed basis, the modem devices use
DLEP to report any characteristics of the link (datarate, latency, DLEP to report any characteristics of the link (datarate, latency,
etc.) that have changed. DLEP is independent of the link type and etc.) that have changed. DLEP is independent of the link type and
topology supported by the modem. Note that the DLEP protocol is topology supported by the modem. Note that the DLEP protocol is
specified to run only on the local link between router and modem. specified to run only on the local link between router and modem.
Some over the air signaling may be necessary between the local and Some over the air signaling may be necessary between the local and
remote modem in order to provide some parameters in DLEP messages remote modem in order to provide some parameters in DLEP messages
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Figure 2: DLEP Network with Multiple Modem Devices Figure 2: DLEP Network with Multiple Modem Devices
1.1. Requirements 1.1. Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14, RFC 2119 [RFC2119]. 14, RFC 2119 [RFC2119].
DLEP requires that the MAC address for delivering data traffic is the
MAC address used by DLEP to identify the destination. No
manipulation or substitution is performed; the MAC address supplied
in all destination messages is used as the OSI Layer 2 Destination
MAC address. DLEP also requires that MAC addresses are unique within
the context of a router-modem session.
The reliance on MAC addresses by DLEP forces the requirement that
participating DLEP peers are on a single segment (either physical or
logically, via tunneling protocols) at Layer 2.
2. Protocol Overview 2. Protocol Overview
DLEP defines a set of messages used by modems and their attached DLEP defines a set of Messages used by modems and their attached
routers to communicate events that occur on the physical link(s) routers to communicate events that occur on the physical link(s)
managed by the modem: for example, a remote node entering or leaving managed by the modem: for example, a remote node entering or leaving
the network, or that the link has changed. Associated with these the network, or that the link has changed. Associated with these
messages are a set of Data Items - information that describes the Messages are a set of Data Items - information that describes the
remote node (e.g., address information), and/or the characteristics remote node (e.g., address information), and/or the characteristics
of the link to the remote node. Throughout this document, we refer of the link to the remote node. Throughout this document, we refer
to a modems/routers participating in a DLEP session as 'DLEP Peers', to a modems/routers participating in a DLEP session as 'DLEP Peers',
or 'DLEP Participants', unless a specific distinction (e.g. modem or or 'DLEP Participants', unless a specific distinction (e.g. modem or
router) is required. router) is required.
DLEP uses a session-oriented paradigm between the modem device and DLEP uses a session-oriented paradigm between the modem device and
its associated router. If multiple modem devices are attached to a its associated router. If multiple modem devices are attached to a
router (as in Figure 2), or the modem supports multiple connections router (as in Figure 2), or the modem supports multiple connections
(via multiple logical or physical interfaces), then separate DLEP (via multiple logical or physical interfaces), then separate DLEP
sessions exist for each modem or connection. A router and modem form sessions exist for each modem or connection. A router and modem form
a session by completing the discovery and initialization process. a session by completing the discovery and initialization process.
This router-modem session persists unless or until it either (1) This router-modem session persists unless or until it either (1)
times out, based on the absence of traffic (including heartbeats), or times out, based on the absence of DLEP traffic (including
(2) is explicitly torn down by one of the participants. heartbeats), or (2) is explicitly torn down by one of the DLEP
participants.
The router/modem session provides a carrier for information exchange The router/modem session provides a carrier for information exchange
concerning 'destinations' that are available via the modem device. concerning 'destinations' that are available via the modem device.
Destinations can be identified by either the router or the modem, and Destinations can be identified by either the router or the modem, and
represent a specific, addressable location that can be reached via represent a specific, addressable location that can be reached via
the link(s) managed by the modem. A destination can be either the link(s) managed by the modem.
physical or logical.
The example of a physical destination would be that of a remote, far- The DLEP Messages concerning destinations thus become the way for
end router attached via the variable-quality network. routers and modems to maintain, and notify each other about, an
information base representing the physical and logical destinations
accessible via the modem device, as well as the link characteristics
to those destinations.
DLEP indentifies destinations by using the MAC address for delivering
data traffic. No manipulation or substitution is performed; the MAC
address supplied in all destination Messages is used as the OSI Layer
2 Destination MAC address. DLEP therefore requires that MAC
addresses are unique within the context of a router-modem session.
The reliance on MAC addresses by DLEP forces the requirement that
participating DLEP peers are on a single segment (either physical or
logically, via tunneling protocols) at Layer 2.
A destination can be either physical or logical. The example of a
physical destination would be that of a remote, far-end router
attached via the variable-quality network. It should be noted that
for physical destinations the MAC address is the address of the far-
end router, not the modem.
The example of a logical destination is Multicast. Multicast traffic The example of a logical destination is Multicast. Multicast traffic
destined for the variable-quality network (the network accessed via destined for the variable-quality network (the network accessed via
the modem) is handled in IP networks by deriving a Layer 2 MAC the modem) is handled in IP networks by deriving a Layer 2 MAC
address based on the Layer 3 address. Leveraging on this scheme, address based on the Layer 3 address. Leveraging on this scheme,
multicast traffic is supported in DLEP simply by treating the derived multicast traffic is supported in DLEP simply by treating the derived
MAC address as any other destination in the network. To support MAC address as any other destination in the network.
these logical destinations, one of the DLEP participants (typically,
the router) informs the other as to the existence of the logical
destination. The modem, once it is aware of the existence of this
logical destination, reports link characteristics just as it would
for any other destination in the network. The specific algorithms a
modem would use to derive metrics on logical destinations are outside
the scope of this specification, and is left to specific
implementations to decide.
The DLEP messages concerning destinations thus become the way for To support these logical destinations, one of the DLEP participants
routers and modems to maintain, and notify each other about, an (typically, the router) informs the other as to the existence of the
information base representing the physical and logical destinations logical destination. The modem, once it is aware of the existence of
accessible via the modem device, as well as the link characteristics this logical destination, reports link characteristics just as it
to those destinations. would for any other destination in the network. The specific
algorithms a modem would use to derive metrics on logical
destinations are outside the scope of this specification, and is left
to specific implementations to decide.
While this document represents the best efforts of the working group While this document represents the best efforts of the working group
to be functionally complete, it is recognized that extensions to DLEP to be functionally complete, it is recognized that extensions to DLEP
will in all likelihood be necessary as more link types are used. will in all likelihood be necessary as more link types are used.
Such extensions are defined as additional rules of behavior, Such extensions are defined as additional rules of behavior,
messages, data items and/or status codes that are not defined in this Messages, Data Items and/or status codes that are not defined in this
document. DLEP contains a standard mechanism for router and modem document. DLEP contains a standard mechanism for router and modem
implementations to negotiate the available extensions to use on a implementations to negotiate the available extensions to use on a
per-session basis. per-session basis.
2.1. Assumptions 2.1. Assumptions
DLEP specifies UDP multicast for single-hop discovery signaling, and DLEP specifies UDP multicast for single-hop discovery signaling, and
TCP for transport of the control messages. Therefore, DLEP assumes TCP for transport of the Messages. Therefore, DLEP assumes that the
that the modem and router have topologically consistent IP addresses modem and router have topologically consistent IP addresses assigned.
assigned. It is RECOMMENDED that DLEP implementations utilize IPv6 It is RECOMMENDED that DLEP implementations utilize IPv6 link-local
link-local addresses to reduce the administrative burden of address addresses to reduce the administrative burden of address assignment.
assignment. DLEP relies on the guaranteed- delivery of its messages DLEP relies on the guaranteed- delivery of its Messages between
between router and modem, once the 1 hop discovery process is router and modem, once the 1 hop discovery process is complete,
complete, hence, the specification of TCP to carry the messages. hence, the specification of TCP to carry the Messages. Other
Other reliable transports for the protocol are possible, but are reliable transports for the protocol are possible, but are outside
outside the scope of this document. the scope of this document.
DLEP further assumes that security of the implementations (e.g., DLEP further assumes that security of the implementations (e.g.,
authentication of stations, encryption of traffic, or both) is dealt authentication of stations, encryption of traffic, or both) is dealt
with by utilizing Layer 2 security techniques. This reliance on with by utilizing Layer 2 security techniques. This reliance on
Layer 2 mechanisms secures all DLEP messages - both the UDP discovery Layer 2 mechanisms secures all DLEP Messages - both the UDP discovery
messages and the TCP control messages. Signals and the TCP control Messages.
3. Destinations
Destination messages describe the acquisition and loss of network
destinations, and control the flow of information about the
destinations in the several ways. A destination MUST contain a MAC
address; it MAY optionally include a Layer 3 address (or multiple
addresses). The MAC address MAY reference a logical destination, as
in a derived multicast MAC address, as well as a physical device. As
destinations are discovered, DLEP routers and modems build an
information base of destinations accessible via the modem.
DLEP can support MAC addresses in either EUI-48 or EUI-64 format,
with the restriction that all MAC addresses for a given DLEP session
MUST be in the same format, and MUST be consistent with the MAC
address format of the connected modem (e.g., if the modem is
connected to the router with an EUI-48 MAC, all destination addresses
via that modem MUST be expressed in EUI-48 format).
Destination messages trigger creation/maintenance/deletion of
destinations in the information base of the recipient. For example,
a modem will inform its attached router of the presence of a new
destination via the Destination Up message (Section 10.9). Receipt
of a Destination Up causes the router to allocate the necessary
resources, creating an entry in the information base with the
specifics (i.e. MAC Address, Latency, Data Rate, etc.) of the
destination. The loss of a destination is communicated via the
Destination Down message (Section 10.13), and changes in status to
the destination (e.g., varying link quality, or addressing changes)
are communicated via the Destination Update message (Section 10.15).
The information on a given destination will persist in the
implementation's information base until a Destination Down message is
received, indicating that the peer has lost contact or interest with
the remote node, or the implementation transitions to the Session
Termination state.
3.1. Router-requested Destinations
Usually a modem will discover the presence of one or more remote
router/modem pairs and announce each destination's arrival by sending
a corresponding Destination Up message to its peer. However, there
may be times when a router wishes to express an interest in the
status of the link to a logical destination that has yet to be
announced, typically a multicast destination. To facilitate this,
DLEP provides the Destination Announce (Section 10.11) and
Destination Announce Response (Section 10.12) messages. These
messages have similar semantics to the Destination Up and Destination
Up Response messages, but flow from router to modem.
After successfully receiving and processing a Destination Announce
message, a modem then announces changes to the link to the logical
destination via Destination Update messages. A modem MAY refuse a
Destination Announce message by replying with a Destination Announce
Response message with a 'Request Denied' status code, see Table 3.
A Destination Announce message MAY also be used by a router to
request information concerning a destination that it has previously
declined interest in, via the 'Not Interested' status code, see
Table 3, or declared as down, via the Destination Down message.
One of the advantages of implementing DLEP is to leverage the modem's
knowledge of the links between remote destinations allowing routers
to avoid using probed neighbor discovery techniques, therefore modem
implementations SHOULD announce available destinations via the
Destination Up message, rather than relying on Destination Announce
messages.
4. Metrics 3. Metrics
DLEP includes the ability for the router and modem to communicate DLEP includes the ability for the router and modem to communicate
metrics that reflect the characteristics (e.g., datarate, latency) of metrics that reflect the characteristics (e.g., datarate, latency) of
the variable-quality link in use. DLEP does not specify how a given the variable-quality link in use. DLEP does not specify how a given
metric value is to be calculated, rather, the protocol assumes that metric value is to be calculated, rather, the protocol assumes that
metrics have been calculated by a 'best effort', incorporating all metrics have been calculated by a 'best effort', incorporating all
pertinent data that is available to the modem device. pertinent data that is available to the modem device.
DLEP allows for metrics to be sent within two contexts - metrics for DLEP allows for metrics to be sent within two contexts - metrics for
a specific destination within the network (e.g., a specific router), a specific destination within the network (e.g., a specific router),
and per-session (those that apply to all destinations accessed via and per-session (those that apply to all destinations accessed via
the modem). Most metrics can be further subdivided into transmit and the modem). Most metrics can be further subdivided into transmit and
receive metrics. In cases where metrics are provided at session receive metrics. In cases where metrics are provided at session
level, the router MUST propagate the metrics to all entries in its level, the router MUST propagate the metrics to all entries in its
information base for destinations that are accessed via the modem. information base for destinations that are accessed via the modem.
DLEP modem implementations MUST announce all metric items that will DLEP modem implementations MUST announce all metric Data Items that
be reported during the session, and provide default values for those will be reported during the session, and provide default values for
metrics, in the Session Initialization Response message those metrics, in the Session Initialization Response Message
(Section 10.4). In order to use a metric type that was not included (Section 9.6). In order to use a metric type that was not included
in the Session Initialization Response message, modem implementations in the Session Initialization Response Message, modem implementations
MUST terminate the session with the router (via the Session Terminate MUST terminate the session with the router (via the Session Terminate
message (Section 10.7)), and establish a new session. A modem MUST Message (Section 9.9)), and establish a new session.
include the following list of metrics in the Session Initialization
Response message:
o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 11.13)
o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 11.16)
A DLEP modem MAY send metrics both in a session context (via the A DLEP modem MAY send metrics both in a session context (via the
Session Update message) and a specific destination context (via Session Update Message) and a specific destination context (via
Destination Update) at any time. The most recently received metric Destination Update) at any time. The most recently received metric
value MUST take precedence over any earlier value, regardless of value MUST take precedence over any earlier value, regardless of
context - that is: context - that is:
1. If the router receives metrics in a specific destination context 1. If the router receives metrics in a specific destination context
(via the Destination Update message), then the specific (via the Destination Update Message), then the specific
destination is updated with the new metric. destination is updated with the new metric.
2. If the router receives metrics in a modem-wide context (via the 2. If the router receives metrics in a session-wide context (via the
Session Update message), then the metrics for all destinations Session Update Message), then the metrics for all destinations
accessed via the modem MUST be updated with the new metric. accessed via the modem MUST be updated with the new metric.
It is left to implementations to choose sensible default values based It is left to implementations to choose sensible default values based
on their specific characteristics. Modems having static (non- on their specific characteristics. Modems having static (non-
changing) link metric characteristics MAY report metrics only once changing) link metric characteristics MAY report metrics only once
for a given destination (or once on a modem-wide basis, if all for a given destination (or once on a session-wide basis, if all
connections via the modem are of this static nature). connections via the modem are of this static nature).
In addition to communicating existing metrics about the link, DLEP In addition to communicating existing metrics about the link, DLEP
provides a message allowing a router to request a different datarate provides a Message allowing a router to request a different datarate
or latency from the modem. This message is the Link Characteristics or latency from the modem. This Message is the Link Characteristics
Request message (Section 10.17), and gives the router the ability to Request Message (Section 9.18), and gives the router the ability to
deal with requisite increases (or decreases) of allocated datarate/ deal with requisite increases (or decreases) of allocated datarate/
latency in demand-based schemes in a more deterministic manner. latency in demand-based schemes in a more deterministic manner.
5. DLEP Session Flow 4. DLEP Session Flow
All Peers participating in a DLEP session transition through five (5) All DLEP participants of a session transition through a number of
distinct states during the lifetime of a DLEP session: distinct states during the lifetime of a DLEP session:
o Peer Discovery o Peer Discovery
o Session Initialization o Session Initialization
o In-Session o In-Session
o Session Termination o Session Termination
o Session Reset o Session Reset
The Peer Discovery state is OPTIONAL to implement for routers. If it Modems, and routers supporting DLEP discovery, transition through all
is used, this state is the initial state. If it is not used, then a five (5) of the above states. Routers that rely on preconfigured TCP
preconfigured TCP address/port combination MUST be provided to the address/port information start in the Session Initialization state.
router, and the router starts in the Session Initialization state.
Modems MUST support the Peer Discovery state. Modems MUST support the Peer Discovery state.
5.1. Peer Discovery State 4.1. Peer Discovery State
In the Peer Discovery state, if the router implementation supports
IPv6, it SHOULD send UDP packets containing a Peer Discovery signal
(Section 10.1) to the DLEP well-known IPv6 link-local multicast
address (Section 13.8) and port number (Section 13.6), setting the
packet source address to a valid IPv6 link-local address and the
source port to a valid port number.
If the router implementation supports IPv4, it SHOULD send UDP
packets containing a Peer Discovery signal (Section 10.1) to the DLEP
well-known IPv4 link-local multicast address (Section 13.7) and port
number (Section 13.6), setting the packet source address to a valid
local IPv4 address and the source port to a valid port number.
The implementation then waits for a unicast UDP packet containing a
Peer Offer signal (Section 10.2) from a potential DLEP peer modem.
While in the Peer Discovery state, Peer Discovery signals MUST be
sent repeatedly by a DLEP router, at regular intervals. The interval
MUST be a minimum of one second; it SHOULD be a configurable
parameter. Note that this operation (sending Peer Discovery and
waiting for Peer Offer) is outside the DLEP Transaction Model, as the
Transaction Model only describes messages on a TCP session.
In the Peer Discovery state, the DLEP modem implementation MUST
listen for incoming Peer Discovery signals on the DLEP well-known
link-local multicast address and port. The choice of using the well-
known IPv4 or the IPv6 well- known link-local multicast address and
port MUST be made by configuration. On receipt of a valid Peer
Discovery signal, it MUST unicast a Peer Offer signal to the source
address and port of the received UDP packet. Peer Offer signals MAY
contain one or more unicast address/port combinations for TCP-based
communication with the modem, via the IPv4 Connection Point data item
(Section 11.2) or the IPv6 Connection Point data item (Section 11.3),
on which it is prepared to accept an incoming TCP connection. If the
modem does not include an IPv4 Connection Point data item, nor a IPv6
Connection Point data item, then the source address of the packet
containing the Peer Offer signal MUST be used as the address on which
the modem is willing to accept TCP connections.
Upon establishment of a TCP connection, both modem and router enter In the Peer Discovery state, routers that support DLEP discovery MUST
the Session Initialization state. Anything other than Peer Discovery send UDP packets containing a Peer Discovery Signal (Section 9.3) to
signals received on the UDP socket MUST be silently dropped. the DLEP well-known address and port number. For routers supporting
both IPv4 and IPv6 DLEP operation, it is RECOMMENDED that IPv6 be
selected as the transport.
Modems MUST be prepared to accept a TCP connection from a router that The router implementation then waits for a unicast UDP packet
is not using the Discovery mechanism, i.e. a connection attempt that containing a Peer Offer Signal (Section 9.4) from a potential DLEP
occurs without a preceding Peer Discovery signal. peer modem. While in the Peer Discovery state, Peer Discovery
Signals MUST be sent repeatedly by a DLEP router, at regular
intervals. The interval MUST be a minimum of one second; it SHOULD
be a configurable parameter. Note that this operation (sending Peer
Discovery and waiting for Peer Offer) is outside the DLEP Transaction
Model, as the Transaction Model only describes Messages on a TCP
session.
Routers MUST use one or more of the modem address/port combinations Routers MUST use one or more of the modem address/port combinations
from the Peer Offer signal or from a priori configuration to from the Peer Offer Signal or from a priori configuration to
establish a new TCP connection to the modem. If more than one modem establish a new TCP connection to the modem. If more than one modem
address/port combinations is available, router implementations MAY address/port combinations is available, router implementations MAY
use their own heuristics to determine the order in which they are use their own heuristics to determine the order in which they are
tried. It is RECOMMENDED that an implementation attempt to connect tried. If a TCP connection cannot be achieved using any of the
to any announced IPv6 address/port combinations before attempting to address/port combinations and the Discovery mechanism is in use, then
use IPv4 combinations. If a TCP connection cannot be achieved using the router SHOULD resume issuing Peer Discovery Signals. If no IPv4
any of the address/port combinations and the Discovery mechanism is Connection Point Data Items, nor IPv6 Connection Point Data Items are
in use, then the router SHOULD resume issuing Peer Discovery signals. included in the Peer Offer Signal, the router MUST use the source
If no IPv4 Connection Point data items, nor IPv6 Connection Point address of the UDP packet containing the Signal as the IP address,
data items are included in the Peer Offer signal, the router MUST use and the DLEP well-known port number.
the origin address of the UDP packet containing the signal as the IP
address, and the DLEP well-known port number.
Once a TCP connection has been established with the modem, the router In the Peer Discovery state, the modem implementation MUST listen for
begins a new session and enters the Session Initialization state. It incoming Peer Discovery Signals on the DLEP well-known link-local
is up to the router implementation if Peer Discovery signals continue multicast address and port. On receipt of a valid Peer Discovery
to be sent after the device has transitioned to the Session Signal, it MUST unicast a Peer Offer Signal to the source address and
Initialization state. port of the received UDP packet.
5.2. Session Initialization State Modems MUST be prepared to accept a TCP connection from a router that
is not using the Discovery mechanism, i.e. a connection attempt that
occurs without a preceding Peer Discovery Signal.
Upon establishment of a TCP connection, both modem and router enter
the Session Initialization state. It is up to the router
implementation if Peer Discovery Signals continue to be sent after
the device has transitioned to the Session Initialization state.
Modem implementations MUST silently ignore Peer Discovery Signals
from a router with which it already has a TCP connection.
4.2. Session Initialization State
On entering the Session Initialization state, the router MUST send a On entering the Session Initialization state, the router MUST send a
Session Initialization message (Section 10.3) to the modem. The Session Initialization Message (Section 9.5) to the modem. The
router MUST then wait for receipt of a Session Initialization router MUST then wait for receipt of a Session Initialization
Response message (Section 10.4) from the modem. Receipt of the Response Message (Section 9.6) from the modem. Receipt of the
Session Initialization Response message containing a Status data item Session Initialization Response Message containing a Status Data Item
(Section 11.1) with value 'Success', see Table 3, indicates that the (Section 10.1) with status code set to 0 'Success', see Table 4,
modem has received and processed the Session Initialization message, indicates that the modem has received and processed the Session
and the router MUST transition to the In-Session state. Initialization Message, and the router MUST transition to the In-
Session state.
On entering the Session Initialization state, the modem MUST wait for On entering the Session Initialization state, the modem MUST wait for
receipt of a Session Initialization message from the router. Upon receipt of a Session Initialization Message from the router. Upon
receipt of a Session Initialization message, the modem MUST send a receipt of a Session Initialization Message, the modem MUST send a
Session Initialization Response message, and the session MUST Session Initialization Response Message, and the session MUST
transition to the In-Session state. transition to the In-Session state. If the modem receives any
Message other than Session Initialization, or it fails to parse the
received Message, it MUST NOT send any Message, and MUST terminate
the TCP connection and transition to the Session Reset state.
DLEP provides an extension negotiation capability to be used in the DLEP provides an extension negotiation capability to be used in the
Session Initialization state, see Section 7. Extensions supported by Session Initialization state, see Section 6. Extensions supported by
an implementation MUST be declared to potential DLEP peers using the an implementation MUST be declared to potential DLEP peers using the
Extensions Supported data item (Section 11.6). Once both Extensions Supported Data Item (Section 10.6). Once both DLEP peers
participants have exchanged initialization messages, an have exchanged initialization Messages, an implementation MUST NOT
implementation MUST NOT emit any message, signal, data item or status emit any Message, Signal, Data Item or status code associated with an
code associated with an extension that was not specified in the extension that was not specified in the received initialization
received initialization message from its peer. Message from its peer.
If the router receives any message other than a valid Session
Initialization Response, it MUST send a Session Termination message
(Section 10.7) with the 'Unexpected Message' status code, see
Table 3, and transition to the Session Termination state.
If the modem receives any message other than Session Initialization,
or it fails to parse the received message, it MUST NOT send any
message, and MUST terminate the TCP connection and transition to the
Session Reset state.
If an additional metric is to be introduced after the session has
started, the session between router and modem MUST be terminated and
restarted, and the new metric described in the next Session
Initialization Response message.
5.3. In-Session State 4.3. In-Session State
In the In-Session state, messages can flow in both directions between In the In-Session state, Messages can flow in both directions between
participants, indicating changes to the session state, the arrival or DLEP peers, indicating changes to the session state, the arrival or
departure of reachable destinations, or changes of the state of the departure of reachable destinations, or changes of the state of the
links to the destinations. links to the destinations.
The In-Session state is maintained until one of the following The In-Session state is maintained until one of the following
conditions occur: conditions occur:
o A peer terminates the session by sending a Session Termination o The implementation terminates the session by sending a Session
message (Section 10.7)), or, Termination Message (Section 9.9)), or,
o The peer terminates the session, indicated by receiving a Session o The peer terminates the session, indicated by receiving a Session
Termination message. Termination Message.
The peer MUST then transition to the Session Termination state.
Prior to the exchange of Destination Up (Section 10.9) and The implementation MUST then transition to the Session Termination
Destination Up Response (Section 10.10) messages, or Destination
Announce (Section 10.11) and Destination Announce Response
(Section 10.12) messages, no messages concerning the logical
destination identified by the MAC Address data item (Section 11.7)
may be sent. A peer receiving any message with such an unannounced
destination MUST terminate the session by issuing a Session
Termination message (Section 10.7) with a status code of 'Invalid
Destination', see Table 3, and transition to the Session Termination
state. state.
The router receiving a Destination Up message MAY decline further 4.3.1. Heartbeats
messages concerning a given destination by sending a Destination Up
Response with a status code of 'Not Interested'. Modems receiving
such responses MUST NOT send further messages concerning that
destination to the router.
After exchanging Destination Down (Section 10.13) and Destination
Down Response (Section 10.14) messages, no messages concerning the
logical destination identified by the MAC Address data item may be a
sent without previously sending a new Destination Up message. A peer
receiving a message about a destination previously announced as
'down' MUST terminate the session by issuing a Session Termination
message with a status code of 'Invalid Destination' and transition to
the Session Termination state.
5.3.1. Heartbeats
In order to maintain the In-Session state, periodic Heartbeat In order to maintain the In-Session state, periodic Heartbeat
messages (Section 10.16) MAY be exchanged between router and modem. Messages (Section 9.20) MUST be exchanged between router and modem.
These messages are intended to keep the session alive, and to verify These Messages are intended to keep the session alive, and to verify
bidirectional connectivity between the two participants. bidirectional connectivity between the two DLEP peers.
If Heartbeat messages are used, the following processing rules MUST
apply:
o Each DLEP peer is responsible for the creation of heartbeat Each DLEP participant is responsible for the creation of Heartbeat
messages. Messages.
o Receipt of any valid DLEP message MUST reset the heartbeat Receipt of any valid DLEP Message MUST reset the heartbeat interval
interval timer (i.e., valid DLEP messages take the place of, and timer (i.e., valid DLEP Messages take the place of, and obviate the
obviate the need for, additional Heartbeat messages). need for, additional Heartbeat Messages).
o DLEP peers SHOULD allow two (2) heartbeat intervals to expire with Implementations SHOULD allow two (2) heartbeat intervals to expire
no messages from the peer before terminating the session by with no Messages from the peer before terminating the session by
issuing a Session Termination message with a status code of 'Timed issuing a Session Termination Message containing a Status Data Item
Out', and then transition to the Session Termination state. (Section 10.1) with status code set to 5 'Timed Out', see Table 4,
and then transition to the Session Termination state.
5.4. Session Termination State 4.4. Session Termination State
When a DLEP implementation enters the Session Termination state after When an implementation enters the Session Termination state after
sending a Session Termination message (Section 10.7) as the result of sending a Session Termination Message (Section 9.9) as the result of
an invalid message or error, it MUST wait for a Session Termination an invalid Message or error, it MUST wait for a Session Termination
Response message (Section 10.8) from its peer. If Heartbeat messages Response Message (Section 9.10) from its peer. Senders SHOULD allow
(Section 10.16) are in use, senders SHOULD allow four (4) heartbeat four (4) heartbeat intervals to expire before assuming that the peer
intervals to expire before assuming that the peer is unresponsive, is unresponsive, and continuing with session termination. Any other
and continuing with session termination. If Heartbeat messages are Message received while waiting MUST be silently ignored.
not in use, then if is RECOMMENDED that an interval of eight (8)
seconds be used.
When the sender of the Session Termination message receives a Session When the sender of the Session Termination Message receives a Session
Termination Response message from its peer, or times out, it MUST Termination Response Message from its peer, or times out, it MUST
transition to the Session Reset state. transition to the Session Reset state.
When an implementation enters the Session Termination state having When an implementation enters the Session Termination state having
received a Session Termination message from its peer, it MUST received a Session Termination Message from its peer, it MUST
immediately send a Session Termination Response and transition to the immediately send a Session Termination Response and transition to the
Session Reset state. Session Reset state.
Any messages received after either sending or receiving a Session 4.5. Session Reset state
Termination message MUST be silently ignored.
5.5. Session Reset state
In the Session Reset state the implementation MUST perform the In the Session Reset state the implementation MUST perform the
following actions: following actions:
o Release all resources allocated for the session. o Release all resources allocated for the session.
o Eliminate all destinations in the information base accessible via o Eliminate all destinations in the information base represented by
the modem represented by the session. Destination Down messages the session. Destination Down Messages (Section 9.15) MUST NOT be
(Section 10.13) MUST NOT be sent. sent.
o Terminate the TCP connection. o Terminate the TCP connection.
Having completed these actions the implementation SHOULD return to Having completed these actions the implementation SHOULD return to
the relevant initial state: Peer Discovery for modems; either Peer the relevant initial state: Peer Discovery for modems; either Peer
Discovery or Session Initialization for routers, depending on Discovery or Session Initialization for routers, depending on
configuration. configuration.
5.5.1. Unexpected TCP connection termination 4.5.1. Unexpected TCP connection termination
If the TCP connection between peers is terminated when a participant If the TCP connection between DLEP peers is terminated when an
is not in the Session Reset state, the implementation MUST implementation is not in the Session Reset state, the implementation
immediately transition to the Session Reset state. MUST immediately transition to the Session Reset state.
6. Transaction Model 5. Transaction Model
DLEP defines a simple message transaction model: Only one request per DLEP defines a simple Message transaction model: Only one request per
destination may be in progress at a time. A message transaction is destination may be in progress at a time per session. A Message
considered complete when a response matching a previously issued transaction is considered complete when a response matching a
request is received. If a participant receives a request for a previously issued request is received. If a DLEP participant
destination for which there is already an outstanding request, the receives a request for a destination for which there is already an
implementation MUST terminate the session by issuing a Session outstanding request, the implementation MUST terminate the session by
Termination message (Section 10.7) with a status code of 'Unexpected issuing a Session Termination Message (Section 9.9) containing a
Message', see Table 3, and transition to the Session Termination Status Data Item (Section 10.1) with status code set to 2 'Unexpected
state. There is no restriction to the total number of message Message', see Table 4, and transition to the Session Termination
state. There is no restriction to the total number of Message
transactions in progress at a time, as long as each transaction transactions in progress at a time, as long as each transaction
refers to a different destination. refers to a different destination.
It should be noted that some requests may take a considerable amount It should be noted that some requests may take a considerable amount
of time for some participants to complete, for example a modem of time for some DLEP participants to complete, for example a modem
handling a multicast destination up request may have to perform a handling a multicast destination up request may have to perform a
complex network reconfiguration. A sending implementation MUST be complex network reconfiguration. A sending implementation MUST be
able to handle such long running transactions gracefully. able to handle such long running transactions gracefully.
Additionally, only one session request, e.g. a Session Initialization Additionally, only one session request, e.g. a Session Initialization
message (Section 10.3) may be in progress at a time. As above, a Message (Section 9.5), may be in progress at a time per session. As
session transaction is considered complete when a response matching a above, a session transaction is considered complete when a response
previously issued request is received. If a participant receives a matching a previously issued request is received. If a DLEP
session request while there is already a session request in progress, participant receives a session request while there is already a
it MUST terminate the session by issuing a Session Termination session request in progress, it MUST terminate the session by issuing
message with a status code of 'Unexpected Message', and transition to a Session Termination Message containing a Status Data Item with
the Session Termination state. Only the Session Termination message status code set to 2 'Unexpected Message', and transition to the
may be issued when a session transaction is in progress. Heartbeat Session Termination state. Only the Session Termination Message may
messages (Section 10.16) MUST NOT be considered part of a session be issued when a session transaction is in progress. Heartbeat
Messages (Section 9.20) MUST NOT be considered part of a session
transaction. transaction.
DLEP transactions do not time out and are not cancellable. An DLEP transactions do not time out and are not cancellable. An
implementation can detect if its peer has failed in some way by use implementation can detect if its peer has failed in some way by use
of the session heartbeat mechanism during the In-Session state, see of the session heartbeat mechanism during the In-Session state, see
Section 5.3. Section 4.3.
7. Extensions 6. Extensions
Extensions MUST be negotiated on a per-session basis during session Extensions MUST be negotiated on a per-session basis during session
initialization via the Extensions Supported mechanism. initialization via the Extensions Supported mechanism.
Implementations are not required to support any extension in order to Implementations are not required to support any extension in order to
be considered DLEP compliant. An extension document, describing the be considered DLEP compliant. An extension document, describing the
operation of a credit windowing scheme for flow control, is described operation of a credit windowing scheme for flow control, is described
in [CREDIT]. in [CREDIT].
If interoperable protocol extensions are required, they MUST be If interoperable protocol extensions are required, they MUST be
standardized either as an update to this document, or as an standardized either as an update to this document, or as an
additional stand-alone specification. The requests for IANA- additional stand-alone specification. The requests for IANA-
controlled registries in this document contain sufficient Reserved controlled registries in this document contain sufficient Reserved
space for DLEP signals, messages, data items and status codes to space for DLEP Signals, Messages, Data Items and status codes to
accommodate future extensions to the protocol. accommodate future extensions to the protocol.
As multiple protocol extensions MAY be announced during session As multiple protocol extensions MAY be announced during session
initialization, authors of protocol extensions MUST consider the initialization, authors of protocol extensions MUST consider the
interaction of their extension with other published extensions, and interaction of their extension with other published extensions, and
specify any incompatibilities. specify any incompatibilities.
7.1. Experiments 6.1. Experiments
This document requests Private Use numbering space in the DLEP This document requests Private Use numbering space in the DLEP
signal/message, data item and status code registries for experimental Signal, Message, Data Item and status code registries for
extensions. The intent is to allow for experimentation with new experimental extensions. The intent is to allow for experimentation
signals, messages, data items, and/or status codes, while still with new Signals, Messages, Data Items, and/or status codes, while
retaining the documented DLEP behavior. still retaining the documented DLEP behavior.
Use of the Private Use signals, messages, data items, status codes, Use of the Private Use Signals, Messages, Data Items, status codes,
or behaviors MUST be announced as DLEP Extensions, during session or behaviors MUST be announced as DLEP Extensions, during session
initialization, using extension identifiers from the Private Use initialization, using extension identifiers from the Private Use
space in the Extensions Supported registry (Table 4), with a value space in the Extensions Supported registry (Table 5), with a value
agreed upon (a priori) between the participating peers. DLEP agreed upon (a priori) between the participating peers. DLEP
extensions using the Private Use numbering space are commonly extensions using the Private Use numbering space are commonly
referred to as Experiments. referred to as Experiments.
Multiple experiments MAY be announced in the Session Initialization Multiple experiments MAY be announced in the Session Initialization
messages. However, use of multiple experiments in a single session Messages. However, use of multiple experiments in a single session
could lead to interoperability issues or unexpected results (e.g., could lead to interoperability issues or unexpected results (e.g.,
clashes of experimental signals, messages, data items and/or status clashes of experimental Signals, Messages, Data Items and/or status
code types), and is therefore discouraged. It is left to code types), and is therefore discouraged. It is left to
implementations to determine the correct processing path (e.g., a implementations to determine the correct processing path (e.g., a
decision on whether to terminate the session, or to establish a decision on whether to terminate the session, or to establish a
precedence of the conflicting definitions) if such conflicts arise. precedence of the conflicting definitions) if such conflicts arise.
8. Scalability 7. Scalability
The protocol is intended to support thousands of destinations on a The protocol is intended to support thousands of destinations on a
given modem/router pair. At large scale, implementations SHOULD given modem/router pair. At large scale, implementations SHOULD
consider employing techniques to prevent flooding a peer with a large consider employing techniques to prevent flooding a peer with a large
number of messages in a short time. It is recommended that number of Messages in a short time. It is recommended that
implementations consider a dampening algorithm to prevent a flapping implementations consider a dampening algorithm to prevent a flapping
device from generating a large number of Destination Up/Destination device from generating a large number of Destination Up/Destination
Down messages, for example. Implementations SHOULD also consider Down Messages, for example. Implementations SHOULD also consider
techniques such as a hysteresis to lessen the impact of rapid, minor techniques such as a hysteresis to lessen the impact of rapid, minor
fluctuations in link quality. The specific algorithms to be used for fluctuations in link quality. The specific algorithms to be used for
handling flapping destinations and minor changes in link quality are handling flapping destinations and minor changes in link quality are
outside the scope of this specification. outside the scope of this specification.
9. DLEP Signal and Message Structure 8. DLEP Signal and Message Structure
DLEP defines two protocol units used in two different ways: Signals DLEP defines two protocol units used in two different ways: Signals
and Messages. Signals are only used in the Discovery mechanism and and Messages. Signals are only used in the Discovery mechanism and
are carried in UDP datagrams. Messages are used bi-directionally are carried in UDP datagrams. Messages are used bi-directionally
over a TCP connection between two peers, in the Session over a TCP connection between two peers, in the Session
Initialization, In-Session and Session Termination states. Initialization, In-Session and Session Termination states.
Both signals and messages consist of a header followed by an Both Signals and Messages consist of a Header followed by an
unordered list of data items. Headers consist of Type and Length unordered list of Data Items. Headers consist of Type and Length
information, while data items are encoded as TLV (Type-Length-Value) information, while Data Items are encoded as TLV (Type-Length-Value)
structures. In this document, the data items following a signal or structures. In this document, the Data Items following a Signal or
message header are described as being 'contained in' the signal or Message Header are described as being 'contained in' the Signal or
message. Message.
There is no restriction on the order of data items following a There is no restriction on the order of Data Items following a
header, and the multiplicity of duplicate data items is defined by Header, and the multiplicity of duplicate Data Items is defined by
the definition of the signal or message declared by the type in the the definition of the Signal or Message declared by the type in the
header. Header.
All integers in header fields and values MUST be in network byte- All integers in Header fields and values MUST be in network byte-
order. order.
9.1. DLEP Signal Header 8.1. DLEP Signal Header
The DLEP signal header contains the following fields: The DLEP Signal Header contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 'D' | 'L' | 'E' | 'P' | | 'D' | 'L' | 'E' | 'P' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signal Type | Length | | Signal Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: DLEP Signal Header Figure 3: DLEP Signal Header
"DLEP": Every signal MUST start with the characters: U+44, U+4C, "DLEP": Every Signal MUST start with the characters: U+0044, U+004C,
U+45, U+50. U+0045, U+0050.
Signal Type: An 16-bit unsigned integer containing one of the DLEP Signal Type: A 16-bit unsigned integer containing one of the DLEP
Signal/Message Type values defined in this document. Signal Type values defined in this document.
Length: The length in octets, expressed as a 16-bit unsigned Length: The length in octets, expressed as a 16-bit unsigned
integer, of all of the DLEP data items associated with this integer, of all of the DLEP Data Items associated with this
signal. This length SHALL NOT include the length of the header Signal. This length MUST NOT include the length of the Signal
itself. Header itself.
The DLEP signal header is immediately followed by one or more DLEP
data items, encoded in TLVs, as defined in this document.
If an unrecognized, or unexpected signal is received, or a received The DLEP Signal Header is immediately followed by zero or more DLEP
signal contains unrecognized, invalid, or disallowed duplicate data Data Items, encoded in TLVs, as defined in this document.
items, the receiving participant MUST ignore the signal.
9.2. DLEP Message Header 8.2. DLEP Message Header
The DLEP message header contains the following fields: The DLEP Message Header contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Length | | Message Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: DLEP Message Header Figure 4: DLEP Message Header
Message Type: An 16-bit unsigned integer containing one of the DLEP Message Type: A 16-bit unsigned integer containing one of the DLEP
Signal/Message Type values defined in this document. Message Type values defined in this document.
Length: The length in octets, expressed as a 16-bit unsigned Length: The length in octets, expressed as a 16-bit unsigned
integer, of all of the DLEP data items associated with this integer, of all of the DLEP Data Items associated with this
message. This length SHALL NOT include the length of the header Message. This length MUST NOT include the length of the Message
itself. Header itself.
The DLEP message header is immediately followed by one or more DLEP
data items, encoded in TLVs, as defined in this document.
If an unrecognized, or unexpected message is received, or a received The DLEP Message Header is immediately followed by zero or more DLEP
message contains unrecognized, invalid, or disallowed duplicate data Data Items, encoded in TLVs, as defined in this document.
items, the receiving participant MUST issue a Session Termination
message (Section 10.7) with a Status data item (Section 11.1)
containing the most relevant status code, see Table 3, and transition
to the Session Termination state.
9.3. DLEP Generic Data Item 8.3. DLEP Generic Data Item
All DLEP data items contain the following fields: All DLEP Data Items contain the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value... : | Value... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: DLEP Generic Data Item Figure 5: DLEP Generic Data Item
Data Item Type: An 16-bit unsigned integer field specifying the type Data Item Type: A 16-bit unsigned integer field specifying the type
of data item being sent. of Data Item being sent.
Length: The length in octets, expressed as an 16-bit unsigned Length: The length in octets, expressed as a 16-bit unsigned
integer, of the value field of the data item. This length SHALL integer, of the Value field of the Data Item. This length MUST
NOT include the length of the header itself. NOT include the length of the Data Item Type and Length fields.
Value: A field of <Length> octets, which contains data specific to a Value: A field of <Length> octets, which contains data specific to a
particular data item. particular Data Item.
10. DLEP Signals and Messages 9. DLEP Signals and Messages
As mentioned above, all DLEP signals begin with the DLEP signal As mentioned above, all DLEP Signals begin with the DLEP Signal
header, and all DLEP messages begin with the DLEP message header. Header, and all DLEP Messages begin with the DLEP Message Header.
Therefore, in the following descriptions of specific signals and Therefore, in the following descriptions of specific Signals and
messages, this header is assumed, and will not be replicated. Messages, this Header is assumed, and will not be replicated.
Following is the set of core signals and messages that MUST be Following is the set of core Signals and Messages that MUST be
recognized by a DLEP compliant implementation. As mentioned before, recognized by a DLEP compliant implementation. As mentioned before,
not all messages may be used during a session, but an implementation not all Messages may be used during a session, but an implementation
MUST correctly process these messages when received. MUST correctly process these Messages when received.
The core DLEP signals and messages are:
+-------------+-----------------------------------------------------+ The core DLEP Signals are:
| Type Code | Description |
+-------------+-----------------------------------------------------+
| 0 | Reserved |
| 1 | Peer Discovery signal (Section 10.1) |
| 2 | Peer Offer signal (Section 10.2) |
| 3 | Session Initialization message (Section 10.3) |
| 4 | Session Initialization Response message (Section |
| | 10.4) |
| 5 | Session Update message (Section 10.5) |
| 6 | Session Update Response message (Section 10.6) |
| 7 | Session Termination message (Section 10.7) |
| 8 | Session Termination Response message (Section 10.8) |
| 9 | Destination Up message (Section 10.9) |
| 10 | Destination Up Response message (Section 10.10) |
| 11 | Destination Down message (Section 10.13) |
| 12 | Destination Down Response message (Section 10.14) |
| 13 | Destination Update message (Section 10.15) |
| 14 | Heartbeat message (Section 10.16) |
| 15 | Link Characteristics Request message (Section |
| | 10.17) |
| 16 | Link Characteristics Response message (Section |
| | 10.18) |
| 17 | Destination Announce message (Section 10.11) |
| 18 | Destination Announce Response message (Section |
| | 10.12) |
| 19-65519 | Reserved for future extensions |
| 65520-65534 | Private Use. Available for experiments |
| 65535 | Reserved |
+-------------+-----------------------------------------------------+
Table 1: DLEP Signal/Message types +--------------+-----------------------------------------+
| Type Code | Description |
+--------------+-----------------------------------------+
| 0 | Reserved |
| 1 | Peer Discovery Signal (Section 9.3) |
| 2 | Peer Offer Signal (Section 9.4) |
| 3-65519 | Reserved for future extensions |
| 65520-65534 | Private Use. Available for experiments |
| 65535 | Reserved |
+--------------+-----------------------------------------+
10.1. Peer Discovery Signal Table 1: DLEP Signal types
A Peer Discovery signal SHOULD be sent by a DLEP router to discover The core DLEP Messages are:
DLEP modems in the network. The Peer Offer signal (Section 10.2) is
required to complete the discovery process. Implementations MUST
implement their own retransmit heuristics in cases where it is
determined the Peer Discovery signal has timed out.
To construct a Peer Discovery signal, the Signal Type value in the +-------------------+-----------------------------------------------+
signal header is set to 1, from Table 1. | Type Code | Description |
+-------------------+-----------------------------------------------+
| 0 | Reserved |
| 1 | Session Initialization Message (Section 9.5) |
| 2 | Session Initialization Response Message |
| | (Section 9.6) |
| 3 | Session Update Message (Section 9.7) |
| 4 | Session Update Response Message (Section 9.8) |
| 5 | Session Termination Message (Section 9.9) |
| 6 | Session Termination Response Message (Section |
| | 9.10) |
| 7 | Destination Up Message (Section 9.11) |
| 8 | Destination Up Response Message (Section |
| | 9.12) |
| 9 | Destination Announce Message (Section 9.13) |
| 10 | Destination Announce Response Message |
| | (Section 9.14) |
| 11 | Destination Down Message (Section 9.15) |
| 12 | Destination Down Response Message (Section |
| | 9.16) |
| 13 | Destination Update Message (Section 9.17) |
| 14 | Link Characteristics Request Message (Section |
| | 9.18) |
| 15 | Link Characteristics Response Message |
| | (Section 9.19) |
| 16 | Heartbeat Message (Section 9.20) |
| 17-65519 | Reserved for future extensions |
| 65520-65534 | Private Use. Available for experiments |
| 65535 | Reserved |
+-------------------+-----------------------------------------------+
The Peer Discovery signal MAY contain the following data item: Table 2: DLEP Message types
o Peer Type (Section 11.4) 9.1. General Processing Rules
10.2. Peer Offer Signal If an unrecognized, or unexpected Signal is received, or a received
Signal contains unrecognized, invalid, or disallowed duplicate Data
Items, the receiving DLEP peer MUST ignore the Signal.
A Peer Offer signal MUST be sent by a DLEP modem in response to a If an unrecognized Message is received, the receiving DLEP peer MUST
valid Peer Discovery signal (Section 10.1). issue a Session Termination Message (Section 9.9) containing a Status
Data Item (Section 10.1) with status code set to 1 'Unknown Message',
see Table 4, and transition to the Session Termination state.
The Peer Offer signal MUST be sent to the unicast address of the If an unexpected Message is received, the receiving DLEP peer MUST
originator of the Peer Discovery signal. issue a Session Termination Message containing a Status Data Item
with status code set to 2 'Unexpected Message', and transition to the
Session Termination state.
To construct a Peer Offer signal, the Signal Type value in the signal If a received Message contains unrecognized, invalid, or disallowed
header is set to 2, from Table 1. duplicate Data Items, the receiving DLEP peer MUST issue a Session
Termination Message containing a Status Data Item with status code
set to 3 'Invalid Data', and transition to the Session Termination
state.
The Peer Offer signal MAY contain the following data item: Prior to the exchange of Destination Up (Section 9.11) and
Destination Up Response (Section 9.12) Messages, or Destination
Announce (Section 9.13) and Destination Announce Response
(Section 9.14) Messages, no Messages concerning a destination may be
sent. A peer receiving any Message with such an unannounced
destination MUST terminate the session by issuing a Session
Termination Message containing a Status Data Item with status code
set to 4 'Invalid Destination', and transition to the Session
Termination state.
o Peer Type (Section 11.4) After exchanging Destination Down (Section 9.15) and Destination Down
Response (Section 9.16) Messages, no Messages concerning a
destination may be a sent until a new Destination Up or Destination
Announce Message is sent. A peer receiving a Message about a
destination previously announced as 'down' MUST terminate the session
by issuing a Session Termination Message with a Status Data Item with
status code set to 4 'Invalid Destination', and transition to the
Session Termination state.
The Peer Offer signal MAY contain one or more of any of the following 9.2. Status code processing
data items, with different values: The behaviour of a DLEP participant receiving a Message containing a
Status Data Item (Section 10.1) is defined by the failure mode
associated with the value of the status code field, see Table 4.
Except for the reserved value of 255, all status code values greater
than or equal to 100 have a failure mode of 'Continue', all other
status codes have a failure mode of 'Terminate'.
o IPv4 Connection Point (Section 11.2) A DLEP participant receiving any Message apart from Session
Termination Message (Section 9.9) containing a Status Data Item with
a status code value with failure mode 'Terminate' MUST immediately
issue a Session Termination Message containing an identical Status
Data Item, and then transition to the Session Termination state.
o IPv6 Connection Point (Section 11.3) A DLEP participant receiving a Message containing a Status Data Item
with a status code value with failure mode 'Continue' can continue
normal operation of the session.
The IP Connection Point data items indicate the unicast address the 9.3. Peer Discovery Signal
router MUST use when connecting the DLEP TCP session. If multiple IP
Connection Point data items are present in the Peer Offer signal,
router implementations MAY use their own heuristics to select the
address to connect to. If no IP Connection Point data items are
included in the Peer Offer signal, the router MUST use the origin
address of the signal as the IP address, and the DLEP well-known port
number (Section 13.6) to establish the TCP connection.
10.3. Session Initialization Message A Peer Discovery Signal SHOULD be sent by a DLEP router to discover
DLEP modems in the network.
A Session Initialization message MUST be sent by a DLEP router as the To construct a Peer Discovery Signal, the Signal Type value in the
first message of the DLEP TCP session. It is sent by the router Signal Header is set to 1, from Table 1.
after a TCP connect to an address/port combination that was obtained
either via receipt of a Peer Offer, or from a priori configuration.
If any optional extensions are supported by the implementation, they The Peer Discovery Signal MAY contain a Peer Type Data Item
MUST be enumerated in the Extensions Supported data item. If an (Section 10.4).
Extensions Supported data item does not exist in a Session
Initialization message, the modem MUST conclude that there is no
support for extensions in the router.
Implementations supporting the Heartbeat Interval (Section 11.5) Implementations MUST implement their own retransmit heuristics in
should understand that heartbeats are not fully established until cases where it is determined the Peer Discovery Signal has timed out.
receipt of Session Initialization Response message (Section 10.4),
and should therefore implement their own timeout and retry heuristics
for this message.
To construct a Session Initialization message, the Message Type value 9.4. Peer Offer Signal
in the message header is set to 3, from Table 1.
The Session Initialization message MUST contain one of each of the A Peer Offer Signal MUST be sent by a DLEP modem to the unicast
following data items: address of the originator of a valid Peer Discovery Signal
(Section 9.3). The Peer Offer Signal is completes the discovery
process.
o Heartbeat Interval (Section 11.5) To construct a Peer Offer Signal, the Signal Type value in the Signal
Header is set to 2, from Table 1.
The Session Initialization message MAY contain one of each of the The Peer Offer Signal MAY contain a Peer Type Data Item
following data items: (Section 10.4).
o Peer Type (Section 11.4) The Peer Offer Signal MAY contain one or more of any of the following
Data Items, with different values:
o Extensions Supported (Section 11.6) o IPv4 Connection Point (Section 10.2)
o IPv6 Connection Point (Section 10.3)
A Session Initialization message MUST be acknowledged by the modem The IP Connection Point Data Items indicate the unicast address the
issuing a Session Initialization Response message (Section 10.4). router MUST use when connecting the DLEP TCP session. If multiple IP
Connection Point Data Items are present in the Peer Offer Signal,
router implementations MAY use their own heuristics to select the
address to connect to. If no IP Connection Point Data Items are
included in the Peer Offer Signal, the router MUST use the source
address of the Signal as the IP address, and the DLEP well-known port
number (Section 12.7) to establish the TCP connection.
As an exception to the general rule that an implementation receiving 9.5. Session Initialization Message
an unrecognized data item in a message terminating the session with
an error, see Section 9.2, if a Session Initialization message
contains one or more Extension Supported data items announcing
support for extensions that the implementation does not recognize,
then the implementation MAY ignore data items it does not recognize.
10.4. Session Initialization Response Message A Session Initialization Message MUST be sent by a DLEP router as the
first Message of the DLEP TCP session. It is sent by the router
after a TCP connect to an address/port combination that was obtained
either via receipt of a Peer Offer, or from a priori configuration.
A Session Initialization Response message MUST be sent in response to To construct a Session Initialization Message, the Message Type value
a received Session Initialization message (Section 10.3). The in the Message Header is set to 1, from Table 2.
Session Initialization Response message completes the DLEP session
establishment; the modem should transition to the In-Session state
when the message is sent, and the router should transition to the In-
Session state upon receipt of an acceptable Session Initialization
Response message.
All supported metric data items MUST be included in the Session The Session Initialization Message MUST contain a Heartbeat Interval
Initialization Response message, with default values to be used on a Data Item (Section 10.5).
'modem-wide' basis. This can be viewed as the modem 'declaring' all
supported metrics at DLEP session initialization. Receipt of any
DLEP message containing a metric data item not included in the
Session Initialization Response message MUST be treated as an error,
resulting in the termination of the DLEP session between router and
modem.
If any optional extensions are supported by the modem, they MUST be The Session Initialization Message MAY contain one of each of the
enumerated in the Extensions Supported data item. If an Extensions following Data Items:
Supported data item does not exist in a Session Initialization
Response message, the router MUST conclude that there is no support
for extensions in the modem.
After the Session Initialization/Session Initialization Response o Peer Type (Section 10.4)
messages have been successfully exchanged, implementations MUST only
use extensions that are supported by BOTH participants.
To construct a Session Initialization Response message, the Message o Extensions Supported (Section 10.6)
Type value in the message header is set to 4, from Table 1.
The Session Initialization Response message MUST contain one of each If any optional extensions are supported by the implementation, they
of the following data items: MUST be enumerated in the Extensions Supported Data Item. If an
Extensions Supported Data Item does not exist in a Session
Initialization Message, the modem MUST conclude that there is no
support for extensions in the router.
o Heartbeat Interval (Section 11.5) DLEP Heartbeats are not fully established until receipt of Session
Initialization Response Message (Section 9.6), and therefore
implementations must use their own timeout and retry heuristics for
this Message.
o Maximum Data Rate (Receive) (Section 11.12) As an exception to the general rule governing an implementation
receiving an unrecognized Data Item in a Message, see Section 9.1, if
a Session Initialization Message contains one or more Extension
Supported Data Items announcing support for extensions that the
implementation does not recognize, then the implementation MAY ignore
Data Items it does not recognize.
o Maximum Data Rate (Transmit) (Section 11.13) 9.6. Session Initialization Response Message
o Current Data Rate (Receive) (Section 11.14) A Session Initialization Response Message MUST be sent in response to
a received Session Initialization Message (Section 9.5).
o Current Data Rate (Transmit) (Section 11.15) To construct a Session Initialization Response Message, the Message
Type value in the Message Header is set to 2, from Table 2.
o Latency (Section 11.16) The Session Initialization Response Message MUST contain one of each
of the following Data Items:
The Session Initialization Response message MUST contain one of each o Status (Section 10.1)
of the following data items, if the data item will be used during the
lifetime of the session:
o Resources (Receive) (Section 11.17) o Heartbeat Interval (Section 10.5)
o Resources (Transmit) (Section 11.18) o Maximum Data Rate (Receive) (Section 10.12)
o Relative Link Quality (Receive) (Section 11.19) o Maximum Data Rate (Transmit) (Section 10.13)
o Relative Link Quality (Transmit) (Section 11.20) o Current Data Rate (Receive) (Section 10.14)
o Maximum Transmission Unit (MTU) (Section 11.21) o Current Data Rate (Transmit) (Section 10.15)
The Session Initialization Response message MAY contain one of each o Latency (Section 10.16)
of the following data items:
o Status (Section 11.1) The Session Initialization Response Message MUST contain one of each
of the following Data Items, if the Data Item will be used during the
lifetime of the session:
o Peer Type (Section 11.4) o Resources (Section 10.17)
o Extensions Supported (Section 11.6)
A router receiving a Session Initialization Response message without o Relative Link Quality (Receive) (Section 10.18)
a Status data item MUST behave as if a Status data item with code
'Success' had been received, see Table 3.
10.5. Session Update Message o Relative Link Quality (Transmit) (Section 10.19)
A Session Update message MAY be sent by a DLEP participant to o Maximum Transmission Unit (MTU) (Section 10.20)
indicate local Layer 3 address changes, or metric changes on a modem-
wide basis. It should be noted that Session Update messages can be
sent by both routers and modems. For example, addition of an IPv4
address to the router MAY prompt a Session Update message to its
attached modems. Also, for example, a modem that changes its Maximum
Data Rate (Receive) for all destinations MAY reflect that change via
a Session Update message to its attached router(s).
Concerning Layer 3 addresses: If the modem is capable of The Session Initialization Response Message MAY contain one of each
understanding and forwarding this information (via proprietary of the following Data Items:
mechanisms), the address update would prompt any remote DLEP modems
(DLEP-enabled modems in a remote node) to issue a Destination Update
message (Section 10.15) to their local routers with the new (or
deleted) addresses. Modems that do not track Layer 3 addresses
SHOULD silently parse and ignore Layer 3 data items. The Session
Update message MUST be acknowledged with a Session Update Response
message (Section 10.6).
If metrics are supplied with the Session Update message (e.g., o Peer Type (Section 10.4)
Maximum Data Rate), these metrics are considered to be modem-wide,
and therefore MUST be applied to all destinations in the information
base associated with the DLEP session.
To construct a Session Update message, the Message Type value in the o Extensions Supported (Section 10.6)
message header is set to 5, from Table 1. The Session Initialization Response Message completes the DLEP
session establishment; the modem should transition to the In-Session
state when the Message is sent, and the router should transition to
the In-Session state upon receipt of an acceptable Session
Initialization Response Message.
The Session Update message MAY contain one of each of the following All supported metric Data Items MUST be included in the Session
data items: Initialization Response Message, with default values to be used on a
session-wide basis. This can be viewed as the modem 'declaring' all
supported metrics at DLEP session initialization. Receipt of any
further DLEP Message containing a metric Data Item not included in
the Session Initialization Response Message MUST be treated as an
error, resulting in the termination of the DLEP session between
router and modem.
o Maximum Data Rate (Receive) (Section 11.12) If any optional extensions are supported by the modem, they MUST be
enumerated in the Extensions Supported Data Item. If an Extensions
Supported Data Item does not exist in a Session Initialization
Response Message, the router MUST conclude that there is no support
for extensions in the modem.
o Maximum Data Rate (Transmit) (Section 11.13) After the Session Initialization/Session Initialization Response
Messages have been successfully exchanged, implementations MUST only
use extensions that are supported by both DLEP peers.
o Current Data Rate (Receive) (Section 11.14) 9.7. Session Update Message
o Current Data Rate (Transmit) (Section 11.15) A Session Update Message MAY be sent by a DLEP participant to
indicate local Layer 3 address changes, or metric changes on a
session-wide basis.
o Latency (Section 11.16) To construct a Session Update Message, the Message Type value in the
The Session Update message MAY contain one of each of the following Message Header is set to 3, from Table 2.
data items, if the data item is in use by the session:
o Resources (Receive) (Section 11.17) The Session Update Message MAY contain one of each of the following
Data Items:
o Resources (Transmit) (Section 11.18) o Maximum Data Rate (Receive) (Section 10.12)
o Relative Link Quality (Receive) (Section 11.19) o Maximum Data Rate (Transmit) (Section 10.13)
o Relative Link Quality (Transmit) (Section 11.20) o Current Data Rate (Receive) (Section 10.14)
o Maximum Transmission Unit (MTU) (Section 11.21) o Current Data Rate (Transmit) (Section 10.15)
The Session Update message MAY contain one or more of the following o Latency (Section 10.16)
data items, with different values: The Session Update Message MAY contain one of each of the following
Data Items, if the Data Item is in use by the session:
o IPv4 Address (Section 11.8) o Resources (Section 10.17)
o IPv6 Address (Section 11.9) o Relative Link Quality (Receive) (Section 10.18)
A Session Update message MUST be acknowledged by the receiver issuing o Relative Link Quality (Transmit) (Section 10.19)
a Session Update Response message (Section 10.6).
10.6. Session Update Response Message o Maximum Transmission Unit (MTU) (Section 10.20)
A Session Update Response message MUST be sent by implementations to The Session Update Message MAY contain one or more of the following
indicate whether a Session Update message (Section 10.5) was Data Items, with different values:
successfully received.
To construct a Session Update Response message, the Message Type o IPv4 Address (Section 10.8)
value in the message header is set to 6, from Table 1.
The Session Update Response message MAY contain one Status o IPv6 Address (Section 10.9)
(Section 11.1) data item.
A receiver of a Session Update Response message without a Status data If metrics are supplied with the Session Update Message (e.g.,
item MUST behave as if a Status data item with status code 'Success' Maximum Data Rate), these metrics are considered to be session-wide,
had been received, see Table 3. and therefore MUST be applied to all destinations in the information
base associated with the DLEP session.
10.7. Session Termination Message It should be noted that Session Update Messages can be sent by both
routers and modems. For example, addition of an IPv4 address to the
router MAY prompt a Session Update Message to its attached modems.
Also, for example, a modem that changes its Maximum Data Rate
(Receive) for all destinations MAY reflect that change via a Session
Update Message to its attached router(s).
A Session Termination message MUST be sent by a participant when the Concerning Layer 3 addresses: If the modem is capable of
DLEP session needs to be terminated. It should be noted that Session understanding and forwarding this information (via proprietary
Termination messages can be sent by both routers and modems. mechanisms), the address update would prompt any remote DLEP modems
(DLEP-enabled modems in a remote node) to issue a Destination Update
Message (Section 9.17) to their local routers with the new (or
deleted) addresses. Modems that do not track Layer 3 addresses
SHOULD silently ignore Address Data Items.
To construct a Session Termination message, the Message Type value in 9.8. Session Update Response Message
the message header is set to 7, from Table 1.
The Session Termination message MAY contain one Status (Section 11.1) A Session Update Response Message MUST be sent by by a DLEP
data item. participant when a Session Update Message (Section 9.7) is received.
A receiver of a Session Termination message without a Status data To construct a Session Update Response Message, the Message Type
item MUST behave as if a Status data item with status code 'Success', value in the Message Header is set to 4, from Table 2.
see Table 3, implying graceful termination, had been received.
A Session Termination message MUST be acknowledged by the receiver The Session Update Response Message MUST contain a Status Data Item
issuing a Session Termination Response message (Section 10.8). (Section 10.1).
10.8. Session Termination Response Message 9.9. Session Termination Message
A Session Termination Response message MUST be sent by a DLEP A Session Termination Message MUST be sent by a DLEP participant when
participant in response to a received Session Termination message the DLEP session needs to be terminated.
(Section 10.7).
Receipt of a Session Termination Response message completes the tear- To construct a Session Termination Message, the Message Type value in
down of the DLEP session. the Message Header is set to 5, from Table 2.
To construct a Session Termination Response message, the Message Type The Session Termination Message MUST contain Status Data Item
value in the message header is set to 8, from Table 1. (Section 10.1).
The Session Termination Response message MAY contain one Status It should be noted that Session Termination Messages can be sent by
(Section 11.1) data item. both routers and modems.
A receiver of a Session Termination Response message without a Status 9.10. Session Termination Response Message
data item MUST behave as if a Status data item with status code
'Success', see Table 3, implying graceful termination, had been
received.
10.9. Destination Up Message A Session Termination Response Message MUST be sent by a DLEP
participant when a Session Termination Message (Section 9.9) is
recevied.
A Destination Up message MUST be sent by the modem to indicate that a To construct a Session Termination Response Message, the Message Type
new destination has been detected. A Destination Up message MUST be value in the Message Header is set to 6, from Table 2.
acknowledged by the router issuing a Destination Up Response message
(Section 10.10). When a Destination Up message is received and
successfully processed, the router should add knowledge of the new
destination to its information base, indicating that the destination
is accessible via the modem.
To construct a Destination Up message, the Message Type value in the There are no valid Data Items for the Session Termination Response
message header is set to 9, from Table 1. Message.
The Destination Up message MUST contain one of each of the following Receipt of a Session Termination Response Message completes the tear-
data items: down of the DLEP session.
o MAC Address (Section 11.7) 9.11. Destination Up Message
The Destination Up message MAY contain one of each of the following
data items:
o Maximum Data Rate (Receive) (Section 11.12) Destination Up Messages are sent by a modem to inform its attached
router of the presence of a new reachable destination.
o Maximum Data Rate (Transmit) (Section 11.13) To construct a Destination Up Message, the Message Type value in the
Message Header is set to 7, from Table 2.
o Current Data Rate (Receive) (Section 11.14) The Destination Up Message MUST contain a MAC Address Data Item
(Section 10.7).
o Current Data Rate (Transmit) (Section 11.15) The Destination Up Message SHOULD contain one or more of the
following Data Items, with different values:
o Latency (Section 11.16) o IPv4 Address (Section 10.8)
The Destination Up message MAY contain one of each of the following o IPv6 Address (Section 10.9)
data items, if the data item is in use by the session: The Destination Up Message MAY contain one of each of the following
Data Items:
o Resources (Receive) (Section 11.17) o Maximum Data Rate (Receive) (Section 10.12)
o Resources (Transmit) (Section 11.18) o Maximum Data Rate (Transmit) (Section 10.13)
o Relative Link Quality (Receive) (Section 11.19) o Current Data Rate (Receive) (Section 10.14)
o Relative Link Quality (Transmit) (Section 11.20) o Current Data Rate (Transmit) (Section 10.15)
o Maximum Transmission Unit (MTU) (Section 11.21) o Latency (Section 10.16)
The Destination Up message MAY contain one or more of the following The Destination Up Message MAY contain one of each of the following
data items, with different values: Data Items, if the Data Item is in use by the session:
o IPv4 Address (Section 11.8) o Resources (Section 10.17)
o IPv6 Address (Section 11.9) o Relative Link Quality (Receive) (Section 10.18)
o IPv4 Attached Subnet (Section 11.10) o Relative Link Quality (Transmit) (Section 10.19)
o IPv6 Attached Subnet (Section 11.11) o Maximum Transmission Unit (MTU) (Section 10.20)
If the modem has IPv4 and/or IPv6 address information for a The Destination Up Message MAY contain one or more of the following
destination it SHOULD include the relevant data items in the Data Items, with different values:
Destination Up message, reducing the need for the router to probe for
any address.
10.10. Destination Up Response Message o IPv4 Attached Subnet (Section 10.10)
A DLEP router MUST send a Destination Up Response message to indicate o IPv6 Attached Subnet (Section 10.11)
whether a Destination Up message (Section 10.9) was successfully
processed.
To construct a Destination Up Response message, the Message Type A router receiving a Destination Up Message allocates the necessary
value in the message header is set to 10, from Table 1. resources, creating an entry in the information base with the
specifics (i.e. MAC Address, Latency, Data Rate, etc.) of the
destination. The information about this destination will persist in
the router's information base until a Destination Down Message
(Section 9.15) is received, indicating that the modem has lost
contact with the remote node, or the implementation transitions to
the Session Termination state.
The Destination Up Response message MUST contain one MAC Address 9.12. Destination Up Response Message
(Section 11.7) data item.
The Destination Up Response message MAY contain one Status A router MUST send a Destination Up Response Message when a
(Section 11.1) data item. Destination Up Message (Section 9.11) is received.
A modem receiving a Destination Up Response message without a Status To construct a Destination Up Response Message, the Message Type
data item MUST behave as if a Status data item with status code value in the Message Header is set to 8, from Table 2.
'Success' had been received, see Table 3.
10.11. Destination Announce Message The Destination Up Response Message MUST contain one of each of the
following Data Items:
If a router wishes to request information concerning a destination o MAC Address (Section 10.7)
that has not yet been announced by a modem via a Destination Up
message (Section 10.9), it MAY send a Destination Announce message to
the modem.
A Destination Announce message MUST be acknowledged by the modem o Status (Section 10.1)
issuing a Destination Announce Response message (Section 10.12).
To construct a Destination Announce message, the Message Type value A router that wishes to receive further information concerning the
in the message header is set to 17, from Table 1. destination identified in the corresponding Destination Up Message
MUST set the status code of the included Status Data Item to 0
'Success', see Table 4.
The Destination Announce message MUST contain one of each of the If the router has no interest in the destination identified in the
following data items: corresponding Destination Up Message, then it MAY set the status code
of the included Status Data Item to 100 'Not Interested'.
o MAC Address (Section 11.7) A modem receiving a Destination Up Response Message containing a
Status Data Item with status code of any value other than 0 'Success'
MUST NOT send further Destination messages about the destination,
e.g. Destination Down (Section 9.15) or Destination Update
(Section 9.17) with the same MAC address.
The Destination Announce message MAY contain zero or more of the 9.13. Destination Announce Message
following data items, with different values:
o IPv4 Address (Section 11.8) Usually a modem will discover the presence of one or more remote
router/modem pairs and announce each destination's arrival by sending
a corresponding Destination Up Message (Section 9.11) to the router.
However, there may be times when a router wishes to express an
interest in a destination that has yet to be announced, typically a
multicast destination. Destination Announce Messages MAY be sent by
a router to announce such an interest.
o IPv6 Address (Section 11.9) A Destination Announce Message MAY also be used by a router to
request information concerning a destination in which it has
previously declined interest, via the 100 'Not Interested' status
code in a Destination Up Response Message (Section 9.12), see Table
4, or declared as 'down', via the Destination Down Message
(Section 9.15).
10.12. Destination Announce Response Message To construct a Destination Announce Message, the Message Type value
in the Message Header is set to 9, from Table 2.
A DLEP modem MUST send a Destination Announce Response message to The Destination Announce Message MUST contain a MAC Address Data Item
indicate whether a Destination Announce message (Section 10.11) was (Section 10.7).
successfully processed and the destination identified by the MAC
Address data item is available.
When a Destination Announce Response message is received and The Destination Announce Message MAY contain zero or more of the
successfully processed, the router should add knowledge of the new following Data Items, with different values:
destination to its information base, indicating that the destination
is accessible via the modem.
To construct a Destination Announce Response message, the Message o IPv4 Address (Section 10.8)
Type value in the message header is set to 18, from Table 1.
The Destination Announce Response message MUST contain one of each of o IPv6 Address (Section 10.9)
the following data items:
o MAC Address (Section 11.7) One of the advantages of implementing DLEP is to leverage the modem's
knowledge of the links between remote destinations allowing routers
to avoid using probed neighbor discovery techniques, therefore modem
implementations SHOULD announce available destinations via the
Destination Up Message, rather than relying on Destination Announce
Messages.
The Destination Announce Response message MAY contain one of each of 9.14. Destination Announce Response Message
the following data items:
o Maximum Data Rate (Receive) (Section 11.12) A modem MUST send a Destination Announce Response Message when a
Destination Announce Message (Section 9.13) is received.
o Maximum Data Rate (Transmit) (Section 11.13) To construct a Destination Announce Response Message, the Message
Type value in the Message Header is set to 10, from Table 2.
o Current Data Rate (Receive) (Section 11.14) The Destination Announce Response Message MUST contain one of each of
the following Data Items:
o Current Data Rate (Transmit) (Section 11.15) o MAC Address (Section 10.7)
o Latency (Section 11.16) o Status (Section 10.1)
The Destination Announce Response message MAY contain one of each of The Destination Announce Response Message MAY contain one of each of
the following data items, if the data item is in use by the session: the following Data Items:
o Resources (Receive) (Section 11.17) o Maximum Data Rate (Receive) (Section 10.12)
o Resources (Transmit) (Section 11.18) o Maximum Data Rate (Transmit) (Section 10.13)
o Relative Link Quality (Receive) (Section 11.19) o Current Data Rate (Receive) (Section 10.14)
o Relative Link Quality (Transmit) (Section 11.20) o Current Data Rate (Transmit) (Section 10.15)
o Maximum Transmission Unit (MTU) (Section 11.21) o Latency (Section 10.16)
The Destination Announce Response message MAY contain zero or more of The Destination Announce Response Message MAY contain one of each of
the following data items, with different values: the following Data Items, if the Data Item is in use by the session:
o IPv4 Address (Section 11.8) o Resources (Section 10.17)
o IPv6 Address (Section 11.9) o Relative Link Quality (Receive) (Section 10.18)
If the modem has IPv4 and/or IPv6 address information for a o Relative Link Quality (Transmit) (Section 10.19)
destination it SHOULD include the relevant data items in the o Maximum Transmission Unit (MTU) (Section 10.20)
Destination Announce Response message, reducing the need for the
router to probe for any address.
o Status (Section 11.1) If a modem is unable to report information immediately about the
requested information, if the destination is not currently reachable,
for example, the status code in the Status Data Item MUST be set to
101 'Request Denied', see Table 4.
A router receiving a Destination Announce Response message without a After sending a Destination Announce Response Message containing a
Status data item MUST behave as if a Status data item with status Status Data Item with status code of 0 'Success', a modem then
code 'Success' had been received, see Table 3. announces changes to the link to the destination via Destination
Update Messages.
If a modem does not support Destination Announce messages, or the When a successful Destination Announce Response Message is received,
modem is unable to report information immediately about the requested the router should add knowledge of the available destination to its
information, if the destination is not currently accessible, for information base.
example, the status code in the Status data item SHOULD be set to
'Request Denied'.
10.13. Destination Down Message 9.15. Destination Down Message
A DLEP participant MUST send a Destination Down message to report A modem MUST send a Destination Down Message to report when a
when a destination (a remote node or a multicast group) is no longer destination (a remote node or a multicast group) is no longer
reachable. A Destination Down Response message (Section 10.14) MUST reachable.
be sent by the recipient of a Destination Down message to confirm
that the relevant data has been removed from the information base.
To construct a Destination Down message, the Message Type value in A router MAY send a Destination Down Message to report when it no
the message header is set to 11, from Table 1. longer requires information concerning a destination.
The Destination Down message MUST contain one of each of the To construct a Destination Down Message, the Message Type value in
following data items: the Message Header is set to 11, from Table 2.
o MAC Address (Section 11.7) The Destination Down Message MUST contain a MAC Address Data Item
(Section 10.7).
It should be noted that both modem and router may send a Destination It should be noted that both modem and router may send a Destination
Down message to its peer. Down Message to their peer, regardless of which peer initially
indicated the destination to be 'up'.
10.14. Destination Down Response Message
A DLEP participant MUST send a Destination Down Response message to 9.16. Destination Down Response Message
indicate whether a received Destination Down message (Section 10.13)
was successfully processed. If successfully processed, the sender of
the Response MUST have removed all entries in the information base
that pertain to the referenced destination.
To construct a Destination Down Response message, the Message Type A Destination Down Response MUST be sent by the recipient of a
value in the message header is set to 12, from Table 1. Destination Down Message (Section 9.15) to confirm that the relevant
data concerning the destination has been removed from the information
base.
The Destination Down Response message MUST contain one of each of the To construct a Destination Down Response Message, the Message Type
following data items: value in the Message Header is set to 12, from Table 2.
o MAC Address (Section 11.7) The Destination Down Response Message MUST contain one of each of the
The Destination Down Response message MAY contain one of each of the following Data Items:
following data items:
o Status (Section 11.1) o MAC Address (Section 10.7)
A receiver of a Destination Down Response message without a Status o Status (Section 10.1)
data item MUST behave as if a Status data item with status code
'Success' had been received, see Table 3.
10.15. Destination Update Message 9.17. Destination Update Message
A DLEP modem SHOULD send the Destination Update message when it A modem SHOULD send the Destination Update Message when it detects
detects some change in the information base for a given destination some change in the information base for a given destination (remote
(remote node or multicast group). Some examples of changes that node or multicast group). Some examples of changes that would prompt
would prompt a Destination Update message are: a Destination Update Message are:
o Change in link metrics (e.g., Data Rates) o Change in link metrics (e.g., Data Rates)
o Layer 3 addressing change o Layer 3 addressing change
To construct a Destination Update message, the Message Type value in To construct a Destination Update Message, the Message Type value in
the message header is set to 13, from Table 1. the Message Header is set to 13, from Table 2.
The Destination Update message MUST contain one of each of the The Destination Update Message MUST contain a MAC Address Data Item
following data items: (Section 10.7).
o MAC Address (Section 11.7) The Destination Update Message MAY contain one of each of the
following Data Items:
The Destination Update message MAY contain one of each of the o Maximum Data Rate (Receive) (Section 10.12)
following data items:
o Maximum Data Rate (Receive) (Section 11.12) o Maximum Data Rate (Transmit) (Section 10.13)
o Maximum Data Rate (Transmit) (Section 11.13) o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Receive) (Section 11.14) o Current Data Rate (Transmit) (Section 10.15)
o Current Data Rate (Transmit) (Section 11.15) o Latency (Section 10.16)
o Latency (Section 11.16) The Destination Update Message MAY contain one of each of the
following Data Items, if the Data Item is in use by the session:
The Destination Update message MAY contain one of each of the o Resources (Section 10.17)
following data items, if the data item is in use by the session:
o Resources (Receive) (Section 11.17) o Relative Link Quality (Receive) (Section 10.18)
o Resources (Transmit) (Section 11.18) o Relative Link Quality (Transmit) (Section 10.19)
o Relative Link Quality (Receive) (Section 11.19)
o Relative Link Quality (Transmit) (Section 11.20) o Maximum Transmission Unit (MTU) (Section 10.20)
o Maximum Transmission Unit (MTU) (Section 11.21) The Destination Update Message MAY contain one or more of the
following Data Items, with different values:
The Destination Update message MAY contain one or more of the o IPv4 Address (Section 10.8)
following data items, with different values:
o IPv4 Address (Section 11.8) o IPv6 Address (Section 10.9)
o IPv6 Address (Section 11.9) o IPv4 Attached Subnet (Section 10.10)
o IPv4 Attached Subnet (Section 11.10) o IPv6 Attached Subnet (Section 10.11)
o IPv6 Attached Subnet (Section 11.11) It should be noted that this Message has no corresponding response.
10.16. Heartbeat Message 9.18. Link Characteristics Request Message
While Heartbeat messages are not required by DLEP implementations, it The Link Characteristics Request Message MAY be sent by a router to
is strongly RECOMMENDED that Heartbeat messages be used. request that the modem initiate changes for specific characteristics
of the link. The request can reference either a real destination
(e.g., a remote node), or a logical destination (e.g., a multicast
group) within the network.
A Heartbeat message SHOULD be sent by a DLEP participant every N To construct a Link Characteristics Request Message, the Message Type
seconds, where N is defined in the Heartbeat Interval data item of value in the Message Header is set to 14, from Table 2.
the Session Initialization message (Section 10.3) or Session
Initialization Response message (Section 10.4).
Note that implementations setting the Heartbeat Interval to 0 The Link Characteristics Request Message MUST contain one of the
effectively sets the interval to an infinite value, turning off following Data Items:
Heartbeat messages. Great care MUST be taken when exercising this
option.
The message is used by participants to detect when a DLEP session o MAC Address (Section 10.7)
peer (either the modem or the router) is no longer communicating.
Participants SHOULD allow two (2) heartbeat intervals to expire with
no messages from the peer before initiating DLEP session termination
procedures.
To construct a Heartbeat message, the Message Type value in the The Link Characteristics Request Message MUST contain at least one of
message header is set to 14, from Table 1. each of the following Data Items:
There are no valid data items for the Heartbeat message. o Current Data Rate (Receive) (Section 10.14)
10.17. Link Characteristics Request Message o Current Data Rate (Transmit) (Section 10.15)
The Link Characteristics Request message MAY be sent by a DLEP router o Latency (Section 10.16)
to request that the modem initiate changes for specific
characteristics of the link. The request can reference either a real
destination (e.g., a remote node), or a logical destination (e.g., a
multicast group) within the network.
The Link Characteristics Request message MAY contain either a Current The Link Characteristics Request Message MAY contain either a Current
Data Rate (CDRR or CDRT) data item to request a different datarate Data Rate (CDRR or CDRT) Data Item to request a different datarate
than what is currently allocated, a Latency data item to request that than what is currently allocated, a Latency Data Item to request that
traffic delay on the link not exceed the specified value, or both. A traffic delay on the link not exceed the specified value, or both.
Link Characteristics Response message (Section 10.18) is required to
complete the request. Issuing a Link Characteristics Request with
ONLY the MAC Address data item is a mechanism a router MAY use to
request metrics (via the Link Characteristics Response) from its
modem.
The router sending a Link Characteristics Request message should be The router sending a Link Characteristics Request Message should be
aware that a request may take an extended period of time to complete. aware that a request may take an extended period of time to complete.
To construct a Link Characteristics Request message, the Message Type 9.19. Link Characteristics Response Message
value in the message header is set to 15, from Table 1.
The Link Characteristics Request message MUST contain one of each of
the following data items:
o MAC Address (Section 11.7)
The Link Characteristics Request message MAY contain one of each of
the following data items:
o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 11.16) A modem MUST send a Link Characteristics Response Message when a Link
Characteristics Request Message (Section 9.18) is received.
10.18. Link Characteristics Response Message To construct a Link Characteristics Response Message, the Message
Type value in the Message Header is set to 15, from Table 2.
A DLEP modem MUST send a Link Characteristics Response message to The Link Characteristics Response Message MUST contain one of each of
indicate whether a received Link Characteristics Request message the following Data Items:
(Section 10.17) was successfully processed. The Link Characteristics
Response message SHOULD contain a complete set of metric data items,
and MUST contain a full set (i.e. those declared in the Session
Initialization Response message (Section 10.4)), if metrics were
requested by only including a MAC address data item. It MUST contain
the same metric types as the request. The values in the metric data
items in the Link Characteristics Response message MUST reflect the
link characteristics after the request has been processed.
If an implementation is not able to alter the characteristics of the o MAC Address (Section 10.7)
link in the manner requested, then the message MUST contain a Status
data item with status code 'Request Denied', see Table 3.
To construct a Link Characteristics Response message, the Message o Status (Section 10.1)
Type value in the message header is set to 16, from Table 1.
The Link Characteristics Response message MUST contain one of each of The Link Characteristics Response Message SHOULD contain one of each
the following data items: of the following Data Items:
o MAC Address (Section 11.7) o Maximum Data Rate (Receive) (Section 10.12)
The Link Characteristics Response message SHOULD contain one of each o Maximum Data Rate (Transmit) (Section 10.13)
of the following data items:
o Maximum Data Rate (Receive) (Section 11.12) o Current Data Rate (Receive) (Section 10.14)
o Maximum Data Rate (Transmit) (Section 11.13) o Current Data Rate (Transmit) (Section 10.15)
o Current Data Rate (Receive) (Section 11.14) o Latency (Section 10.16)
o Current Data Rate (Transmit) (Section 11.15) The Link Characteristics Response Message MAY contain one of each of
the following Data Items, if the Data Item is in use by the session:
o Latency (Section 11.16) o Resources (Section 10.17)
The Link Characteristics Response message MAY contain one of each of o Relative Link Quality (Receive) (Section 10.18)
the following data items:
o Status (Section 11.1) o Relative Link Quality (Transmit) (Section 10.19)
The Link Characteristics Response message MAY contain one of each of o Maximum Transmission Unit (MTU) (Section 10.20)
the following data items, if the data item is in use by the session:
o Resources (Receive) (Section 11.17) The Link Characteristics Response Message MUST contain a complete set
of metric Data Items, referencing all metrics declared in the Session
Initialization Response Message (Section 9.6). The values in the
metric Data Items in the Link Characteristics Response Message MUST
reflect the link characteristics after the request has been
processed.
o Resources (Transmit) (Section 11.18) If an implementation is not able to alter the characteristics of the
link in the manner requested, then the status code of the Status Data
Item MUST be set to 101 'Request Denied', see Table 4.
o Relative Link Quality (Receive) (Section 11.19) 9.20. Heartbeat Message
o Relative Link Quality (Transmit) (Section 11.20) A Heartbeat Message MUST be sent by a DLEP participant every N
milliseconds, where N is defined in the Heartbeat Interval Data Item
(Section 10.5) of the Session Initialization Message (Section 9.5) or
Session Initialization Response Message (Section 9.6).
o Maximum Transmission Unit (MTU) (Section 11.21) To construct a Heartbeat Message, the Message Type value in the
Message Header is set to 16, from Table 2.
A router receiving a Link Characteristics Response message without a There are no valid Data Items for the Heartbeat Message.
Status data item MUST behave as if a Status data item with status
code 'Success', see Table 3, had been received.
11. DLEP Data Items The Message is used by DLEP peers to detect when a DLEP session peer
(either the modem or the router) is no longer communicating. DLEP
participants SHOULD allow two (2) heartbeat intervals to expire with
no Messages from the DLEP peer before initiating DLEP session
termination procedures.
Following is the list of core data items that MUST be recognized by a 10. DLEP Data Items
DLEP compliant implementation. As mentioned before, not all data
items need be used during a session, but an implementation MUST
correctly process these data items when correctly associated with a
signal or message.
The core DLEP data items are: Following is the list of core Data Items that MUST be recognized by a
DLEP compliant implementation. As mentioned before, not all Data
Items need be used during a session, but an implementation MUST
correctly process these Data Items when correctly associated with a
Signal or Message.
+-------------+-----------------------------------------------------+ The core DLEP Data Items are:
| Type Code | Description |
+-------------+-----------------------------------------------------+
| 0 | Reserved |
| 1 | Status (Section 11.1) |
| 2 | IPv4 Connection Point (Section 11.2) |
| 3 | IPv6 Connection Point (Section 11.3) |
| 4 | Peer Type (Section 11.4) |
| 5 | Heartbeat Interval (Section 11.5) |
| 6 | Extensions Supported (Section 11.6) |
| 7 | MAC Address (Section 11.7) |
| 8 | IPv4 Address (Section 11.8) |
| 9 | IPv6 Address (Section 11.9) |
| 10 | IPv4 Attached Subnet (Section 11.10) |
| 11 | IPv6 Attached Subnet (Section 11.11) |
| 12 | Maximum Data Rate (Receive) MDRR) (Section 11.12) |
| 13 | Maximum Data Rate (Transmit) (MDRT) (Section 11.13) |
| 14 | Current Data Rate (Receive) (CDRR) (Section 11.14) |
| 15 | Current Data Rate (Transmit) (CDRT) (Section 11.15) |
| 16 | Latency (Section 11.16) |
| 17 | Resources (Receive) (RESR) (Section 11.17) |
| 18 | Resources (Transmit) (REST) (Section 11.18) |
| 19 | Relative Link Quality (Receive) (RLQR) (Section |
| | 11.19) |
| 20 | Relative Link Quality (Transmit) (RLQT) (Section |
| | 11.20) |
| 21 | Maximum Transmission Unit (MTU) (Section 11.21) |
| 22-65407 | Reserved for future extensions |
| 65408-65534 | Private Use. Available for experiments |
| 65535 | Reserved |
+-------------+-----------------------------------------------------+
Table 2: DLEP Data Item types +--------------------+----------------------------------------------+
| Type Code | Description |
+--------------------+----------------------------------------------+
| 0 | Reserved |
| 1 | Status (Section 10.1) |
| 2 | IPv4 Connection Point (Section 10.2) |
| 3 | IPv6 Connection Point (Section 10.3) |
| 4 | Peer Type (Section 10.4) |
| 5 | Heartbeat Interval (Section 10.5) |
| 6 | Extensions Supported (Section 10.6) |
| 7 | MAC Address (Section 10.7) |
| 8 | IPv4 Address (Section 10.8) |
| 9 | IPv6 Address (Section 10.9) |
| 10 | IPv4 Attached Subnet (Section 10.10) |
| 11 | IPv6 Attached Subnet (Section 10.11) |
| 12 | Maximum Data Rate (Receive) MDRR) (Section |
| | 10.12) |
| 13 | Maximum Data Rate (Transmit) (MDRT) (Section |
| | 10.13) |
| 14 | Current Data Rate (Receive) (CDRR) (Section |
| | 10.14) |
| 15 | Current Data Rate (Transmit) (CDRT) (Section |
| | 10.15) |
| 16 | Latency (Section 10.16) |
| 17 | Resources (RES) (Section 10.17) |
| 18 | Relative Link Quality (Receive) (RLQR) |
| | (Section 10.18) |
| 19 | Relative Link Quality (Transmit) (RLQT) |
| | (Section 10.19) |
| 20 | Maximum Transmission Unit (MTU) (Section |
| | 10.20) |
| 21-65407 | Reserved for future extensions |
| 65408-65534 | Private Use. Available for experiments |
| 65535 | Reserved |
+--------------------+----------------------------------------------+
11.1. Status Table 3: DLEP Data Item types
The Status data item MAY appear in the Session Initialization 10.1. Status
Response (Section 10.4), Session Termination (Section 10.7), Session
Termination Response (Section 10.8), Session Update Response
(Section 10.6), Destination Up Response (Section 10.10), Destination
Down Response (Section 10.14) and Link Characteristics Response
(Section 10.18) messages.
For the Session Termination message (Section 10.7), the Status data For the Session Termination Message (Section 9.9), the Status Data
item indicates a reason for the termination. For all acknowledgement Item indicates a reason for the termination. For all response
messages, the Status data item is used to indicate the success or Messages, the Status Data Item is used to indicate the success or
failure of the previously received message. failure of the previously received Message.
The status data item includes an optional Text field that can be used The Status Data Item includes an optional Text field that can be used
to provide a textual description of the status. The use of the Text to provide a textual description of the status. The use of the Text
field is entirely up to the receiving implementation, i.e., it could field is entirely up to the receiving implementation, i.e., it could
be output to a log file or discarded. If no Text field is supplied be output to a log file or discarded. If no Text field is supplied
with the Status data item, the Length field MUST be set to 1. with the Status Data Item, the Length field MUST be set to 1.
The Status data item contains the following fields: The Status Data Item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | Text... : | Code | Text... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 1 Data Item Type: 1
Length: 1 + Length of text, in octets Length: 1 + Length of text, in octets
Status Code: One of the codes defined in Table 4 below.
Status Code: One of the codes defined in Table 3 below. Text: UTF-8 encoded string of UNICODE [UNIV8] characters, describing
the cause, used for implementation defined purposes. Since this
Text: UTF-8 encoded string, describing the cause, used for field is used for description, implementations SHOULD limit
implementation defined purposes. Since this field is used for characters in this field to printable characters. Implementations
description, implementations SHOULD limit characters in this field receiving this Data Item SHOULD check for printable characters in
to printable characters. Implementations receiving this data item the field.
SHOULD check for printable characters in the field.
An implementation MUST NOT assume the Text field is NUL-terminated. An implementation MUST NOT assume the Text field is NUL-terminated.
+-------------+---------+-----------+-------------------------------+ +---------------+---------+-----------+-----------------------------+
| Status Code | Value | Failure | Reason | | Status Code | Value | Failure | Reason |
| | | Mode | | | | | Mode | |
+-------------+---------+-----------+-------------------------------+ +---------------+---------+-----------+-----------------------------+
| Success | 0 | Success | The message was processed | | Success | 0 | Success | The Message was processed |
| | | | successfully. | | | | | successfully. |
| Unknown | 1 | Terminate | The message was not | | Unknown | 1 | Terminate | The Message was not |
| Message | | | recognized by the | | Message | | | recognized by the |
| | | | implementation. | | | | | implementation. |
| Unexpected | 2 | Terminate | The message was not expected | | Unexpected | 2 | Terminate | The Message was not |
| Message | | | while the device was in the | | Message | | | expected while the device |
| | | | current state, e.g., a | | | | | was in the current state, |
| | | | Session Initialization | | | | | e.g., a Session |
| | | | message (Section 10.3) in the | | | | | Initialization Message |
| | | | In-Session state. | | | | | (Section 9.5) in the In- |
| Invalid | 3 | Terminate | One or more data items in the | | | | | Session state. |
| Data | | | message are invalid, | | Invalid Data | 3 | Terminate | One or more Data Items in |
| | | | unexpected or incorrectly | | | | | the Message are invalid, |
| | | | duplicated. | | | | | unexpected or incorrectly |
| Invalid | 4 | Terminate | The destination provided in | | | | | duplicated. |
| Destination | | | the message does not match a | | Invalid | 4 | Terminate | The destination included in |
| | | | previously announced | | Destination | | | the Message does not match |
| | | | destination. For example, in | | | | | a previously announced |
| | | | the Link Characteristic | | | | | destination. For example, |
| | | | Response message (Section | | | | | in the Link Characteristic |
| | | | 10.18). | | | | | Response Message (Section |
| Timed Out | 5 | Terminate | The session has timed out. | | | | | 9.19). |
| <Reserved> | 6-90 | Terminate | Reserved for future | | Timed Out | 5 | Terminate | The session has timed out. |
| | | | extensions. | | <Reserved> | 6-90 | Terminate | Reserved for future |
| <Private | 91-99 | Terminate | Available for experiments. | | | | | extensions. |
| Use> | | | | | <Private Use> | 91-99 | Terminate | Available for experiments. |
| Not | 100 | Continue | The receiver is not | | Not | 100 | Continue | The receiver is not |
| Interested | | | interested in this message | | Interested | | | interested in this Message |
| | | | subject, e.g. a Destination | | | | | subject, e.g. in a |
| | | | Up Response message (Section | | | | | Destination Up Response |
| | | | 10.10) to indicate no further | | | | | Message (Section 9.12) to |
| | | | messages about the | | | | | indicate no further |
| | | | destination. | | | | | Messages about the |
| Request | 101 | Continue | The receiver refuses to | | | | | destination. |
| Denied | | | complete the request. | | Request | 101 | Continue | The receiver refuses to |
| <Reserved> | 102-243 | Continue | Reserved for future | | Denied | | | complete the request. |
| | | | extensions. | | <Reserved> | 102-243 | Continue | Reserved for future |
| <Private | 244-254 | Continue | Available for experiments. | | | | | extensions. |
| Use> | | | | | <Private Use> | 244-254 | Continue | Available for experiments. |
| <Reserved> | 255 | Terminate | Reserved. | | <Reserved> | 255 | Terminate | Reserved. |
+-------------+---------+-----------+-------------------------------+ +---------------+---------+-----------+-----------------------------+
Table 3: DLEP Status Codes
A failure mode of 'Terminate' indicates that the session MUST be
terminated immediately instead of sending any relevant response
message, by sending a Session Termination message (Section 10.7)
containing the status code, and then transitioning to the Session
Termination state.
A failure mode of 'Continue' indicates that the session SHOULD
continue as normal.
11.2. IPv4 Connection Point Table 4: DLEP Status Codes
The IPv4 Connection Point data item MAY appear in the Peer Offer 10.2. IPv4 Connection Point
signal (Section 10.2).
The IPv4 Connection Point data item indicates the IPv4 address and, The IPv4 Connection Point Data Item indicates the IPv4 address and,
optionally, the TCP port number on the DLEP modem available for optionally, the TCP port number on the modem available for
connections. If provided, the router MUST use this information to connections. If provided, the router MUST use this information to
perform the TCP connect to the modem. initiate the TCP connection to the modem.
The IPv4 Connection Point data item contains the following fields: The IPv4 Connection Point Data Item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | IPv4 Address... : | Flags | IPv4 Address... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: ...cont. | TCP Port Number (optional) | : ...cont. | TCP Port Number (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 2 Data Item Type: 2
Length: 5 (or 7 if TCP Port included) Length: 5 (or 7 if TCP Port included)
Flags: Flags field, defined below. Flags: Flags field, defined below.
IPv4 Address: The IPv4 address listening on the DLEP modem. IPv4 Address: The IPv4 address listening on the modem.
TCP Port Number: TCP Port number on the DLEP modem. TCP Port Number: TCP Port number on the modem.
If the Length field is 7, the port number specified MUST be used to If the Length field is 7, the port number specified MUST be used to
establish the TCP session. If the TCP Port Number is omitted, i.e. establish the TCP session. If the TCP Port Number is omitted, i.e.
the Length field is 5, the router MUST use the DLEP well-known port the Length field is 5, the router MUST use the DLEP well-known port
number (Section 13.6) to establish the TCP connection. number (Section 12.7) to establish the TCP connection.
The Flags field is defined as: The Flags field is defined as:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved | | Reserved |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
11.3. IPv6 Connection Point 10.3. IPv6 Connection Point
The IPv6 Connection Point data item MAY appear in the Peer Offer
signal (Section 10.2).
The IPv6 Connection Point data item indicates the IPv6 address and, The IPv6 Connection Point Data Item indicates the IPv6 address and,
optionally, the TCP port number on the DLEP modem available for optionally, the TCP port number on the modem available for
connections. If provided, the router MUST use this information to connections. If provided, the router MUST use this information to
perform the TCP connect to the modem. initiate the TCP connection to the modem.
The IPv6 Connection Point data item contains the following fields: The IPv6 Connection Point Data Item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | IPv6 Address : | Flags | IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Address : : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 42, line 46 skipping to change at page 38, line 43
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: ...cont. | TCP Port Number (optional) | : ...cont. | TCP Port Number (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 3 Data Item Type: 3
Length: 17 (or 19 if TCP Port included) Length: 17 (or 19 if TCP Port included)
Flags: Flags field, defined below. Flags: Flags field, defined below.
IPv6 Address: The IPv6 address listening on the DLEP modem. IPv6 Address: The IPv6 address listening on the modem.
TCP Port Number: TCP Port number on the DLEP modem. TCP Port Number: TCP Port number on the modem.
If the Length field is 19, the port number specified MUST be used to If the Length field is 19, the port number specified MUST be used to
establish the TCP session. If the TCP Port Number is omitted, i.e. establish the TCP session. If the TCP Port Number is omitted, i.e.
the Length field is 17, the router MUST use the DLEP well-known port the Length field is 17, the router MUST use the DLEP well-known port
number (Section 13.6) to establish the TCP connection. number (Section 12.7) to establish the TCP connection.
The Flags field is defined as: The Flags field is defined as:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved | | Reserved |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
11.4. Peer Type 10.4. Peer Type
The Peer Type data item MAY appear in the Peer Discovery
(Section 10.1) and Peer Offer (Section 10.2) signals, and the Session
Initialization (Section 10.3) and Session Initialization Response
(Section 10.4) messages.
The Peer Type data item is used by the router and modem to give The Peer Type Data Item is used by the router and modem to give
additional information as to its type. The peer type is a string and additional information as to its type. The peer type is a string and
is envisioned to be used for informational purposes (e.g., as output is envisioned to be used for informational purposes (e.g., as output
in a display command). in a display command).
The Peer Type data item contains the following fields: The Peer Type Data Item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peer Type... : | Peer Type... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 4 Data Item Type: 4
Length: Length of peer type string, in octets. Length: Length of peer type string, in octets.
Peer Type: UTF-8 encoded string. For example, a satellite modem Peer Type: UTF-8 encoded string of UNICODE [UNIV8] characters. For
might set this variable to "Satellite terminal". Since this data example, a satellite modem might set this variable to "Satellite
item is intended to provide additional information for display terminal". Since this Data Item is intended to provide additional
commands, sending implementations SHOULD limit the data to information for display commands, sending implementations SHOULD
printable characters, and receiving implementations SHOULD check limit the data to printable characters, and receiving
the data for printable characters. implementations SHOULD check the data for printable characters.
An implementation MUST NOT assume the Peer Type field is NUL- An implementation MUST NOT assume the Peer Type field is NUL-
terminated. terminated.
11.5. Heartbeat Interval 10.5. Heartbeat Interval
The Heartbeat Interval data item MUST appear in both the Session
Initialization (Section 10.3) and Session Initialization Response
(Section 10.4) messages to indicate the Heartbeat timeout window to
be used by the sender.
The Interval is used to specify a period (in seconds) for Heartbeat The Heartbeat Interval Data Item is used to specify a period in
messages (Section 10.16). By specifying an Interval value of 0, milliseconds for Heartbeat Messages (Section 9.20).
implementations MAY indicate the desire to disable Heartbeat messages
entirely (i.e., the Interval is set to an infinite value). However,
it is RECOMMENDED that implementations use non-0 timer values.
The Heartbeat Interval data item contains the following fields: The Heartbeat Interval Data Item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interval | | Heartbeat Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 5 Data Item Type: 5
Length: 2 Length: 4
Interval: 0 = Do not use heartbeats on this DLEP session. Non-zero
= Interval, in seconds, for heartbeat messages.
11.6. Extensions Supported Heartbeat Interval: The interval in milliseconds, expressed as a
32-bit unsigned integer, for Heartbeat Messages.
This value MUST NOT be 0.
The Extensions Supported data item MAY be used in both the Session 10.6. Extensions Supported
Initialization (Section 10.3) and Session Initialization Response
(Section 10.4) messages.
The Extensions Supported data item is used by the router and modem to The Extensions Supported Data Item is used by the router and modem to
negotiate additional optional functionality they are willing to negotiate additional optional functionality they are willing to
support. The Extensions List is a concatenation of the types of each support. The Extensions List is a concatenation of the types of each
supported extension, found in the IANA DLEP Extensions repository. supported extension, found in the IANA DLEP Extensions repository.
Each Extension Type definition includes which additional signals and Each Extension Type definition includes which additional Signals and
data-items are supported. Data Items are supported.
The Extensions Supported data item contains the following fields: The Extensions Supported Data Item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extensions List... | Extensions List...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 6 Data Item Type: 6
Length: Length of the extensions list in octets. This is twice (2x) Length: Length of the extensions list in octets. This is twice (2x)
the number of extensions. the number of extensions.
Extension List: A list of extensions supported, identified by their Extension List: A list of extensions supported, identified by their
2-octet value as listed in the extensions registry. 2-octet value as listed in the extensions registry.
11.7. MAC Address 10.7. MAC Address
The MAC address data item MUST appear in all destination-oriented The MAC Address Data Item contains the address of the destination on
messages (i.e., Destination Up (Section 10.9), Destination Up the remote node.
Response (Section 10.10), Destination Down (Section 10.13),
Destination Down Response (Section 10.14), Destination Update DLEP can support MAC addresses in either EUI-48 or EUI-64 format,
(Section 10.15), Link Characteristics Request (Section 10.17), and with the restriction that all MAC addresses for a given DLEP session
Link Characteristics Response (Section 10.18)). MUST be in the same format, and MUST be consistent with the MAC
address format of the connected modem (e.g., if the modem is
connected to the router with an EUI-48 MAC, all destination addresses
via that modem MUST be expressed in EUI-48 format).
The MAC Address data item contains the address of the destination on
the remote node. The MAC address MAY be either a physical or a
virtual destination, and MAY be expressed in EUI-48 or EUI-64 format.
Examples of a virtual destination would be a multicast MAC address, Examples of a virtual destination would be a multicast MAC address,
or the broadcast MAC (FF:FF:FF:FF:FF:FF). or the broadcast MAC (FF:FF:FF:FF:FF:FF).
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC Address : | MAC Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 46, line 5 skipping to change at page 41, line 38
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: MAC Address : (if EUI-64 used) | : MAC Address : (if EUI-64 used) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 7 Data Item Type: 7
Length: 6 for EUI-48 format, or 8 for EUI-64 format Length: 6 for EUI-48 format, or 8 for EUI-64 format
MAC Address: MAC Address of the destination. MAC Address: MAC Address of the destination.
11.8. IPv4 Address 10.8. IPv4 Address
The IPv4 Address data item MAY appear in the Session Update
(Section 10.5), Destination Up (Section 10.9) and Destination Update
(Section 10.15) messages.
When included in Destination messages, this data item contains the When included in Destination Messages, this Data Item contains the
IPv4 address of the destination. When included in the Session Update IPv4 address of the destination. When included in the Session Update
message, this data item contains the IPv4 address of the peer. In Message, this Data Item contains the IPv4 address of the peer. In
either case, the data item also contains an indication of whether either case, the Data Item also contains an indication of whether
this is a new or existing address, or is a deletion of a previously this is a new or existing address, or is a deletion of a previously
known address. known address.
The IPv4 Address data item contains the following fields: The IPv4 Address Data Item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | IPv4 Address : | Flags | IPv4 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: ...cont. | : ...cont. |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
skipping to change at page 47, line 5 skipping to change at page 42, line 30
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing A: Add/Drop flag, indicating whether this is a new or existing
address (1), or a withdrawal of an address (0). address (1), or a withdrawal of an address (0).
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
11.9. IPv6 Address 10.9. IPv6 Address
The IPv6 Address data item MAY appear in the Session Update When included in Destination Messages, this Data Item contains the
(Section 10.5), Destination Up (Section 10.9) and Destination Update IPv6 address of the destination. When included in the Session Update
(Section 10.15) messages. When included in Destination messages, Message, this Data Item contains the IPv6 address of the peer. In
this data item contains the IPv6 address of the destination. When either case, the Data Item also contains an indication of whether
included in the Session Update message, this data item contains the this is a new or existing address, or is a deletion of a previously
IPv6 address of the peer. In either case, the data item also known address.
contains an indication of whether this is a new or existing address,
or is a deletion of a previously known address.
The IPv6 Address data item contains the following fields: The IPv6 Address Data Item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | IPv6 Address : | Flags | IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Address : : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 48, line 5 skipping to change at page 43, line 29
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing A: Add/Drop flag, indicating whether this is a new or existing
address (1), or a withdrawal of an address (0). address (1), or a withdrawal of an address (0).
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
11.10. IPv4 Attached Subnet 10.10. IPv4 Attached Subnet
The DLEP IPv4 Attached Subnet allows a device to declare that it has The DLEP IPv4 Attached Subnet allows a device to declare that it has
an IPv4 subnet (e.g., a stub network) attached, that it has become an IPv4 subnet (e.g., a stub network) attached, that it has become
aware of an IPv4 subnet being present at a remote destination, or aware of an IPv4 subnet being present at a remote destination, or
that it has become aware of the loss of a subnet at the remote that it has become aware of the loss of a subnet at the remote
destination. The IPv4 Attached Subnet data item MAY appear in the destination.
Destination Up (Section 10.9) and Destination Update (Section 10.15)
messages.
The DLEP IPv4 Attached Subnet data item contains the following The DLEP IPv4 Attached Subnet Data Item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | IPv4 Attached Subnet : | Flags | IPv4 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: ...cont. |Prefix Length | : ...cont. |Prefix Length |
skipping to change at page 49, line 5 skipping to change at page 44, line 26
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing subnet A: Add/Drop flag, indicating whether this is a new or existing subnet
address (1), or a withdrawal of a subnet address (0). address (1), or a withdrawal of a subnet address (0).
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
11.11. IPv6 Attached Subnet 10.11. IPv6 Attached Subnet
The DLEP IPv6 Attached Subnet allows a device to declare that it has The DLEP IPv6 Attached Subnet allows a device to declare that it has
an IPv6 subnet (e.g., a stub network) attached, or that it has become an IPv6 subnet (e.g., a stub network) attached, that it has become
aware of an IPv6 subnet being present at a remote destination. The aware of an IPv6 subnet being present at a remote destination, or
IPv6 Attached Subnet data item MAY appear in the Destination Up that it has become aware of the loss of a subnet at the remote
(Section 10.9) and Destination Update (Section 10.15) messages. destination.
The DLEP IPv6 Attached Subnet data item contains the following The DLEP IPv6 Attached Subnet Data Item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | IPv6 Attached Subnet : | Flags | IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Attached Subnet : : IPv6 Attached Subnet :
skipping to change at page 50, line 7 skipping to change at page 45, line 28
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing subnet A: Add/Drop flag, indicating whether this is a new or existing subnet
address (1), or a withdrawal of a subnet address (0). address (1), or a withdrawal of a subnet address (0).
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
11.12. Maximum Data Rate (Receive) 10.12. Maximum Data Rate (Receive)
The Maximum Data Rate (Receive) (MDRR) data item MUST appear in the The Maximum Data Rate (Receive) (MDRR) Data Item is used to indicate
Session Initialization Response message (Section 10.4), and MAY the maximum theoretical data rate, in bits per second, that can be
appear in the Session Update (Section 10.5), Destination Up
(Section 10.9), Destination Update (Section 10.15) and Link
Characteristics Response (Section 10.18) messages to indicate the
maximum theoretical data rate, in bits per second, that can be
achieved while receiving data on the link. achieved while receiving data on the link.
The Maximum Data Rate (Receive) data item contains the following The Maximum Data Rate (Receive) Data Item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MDRR (bps) : | MDRR (bps) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: MDRR (bps) | : MDRR (bps) |
skipping to change at page 50, line 33 skipping to change at page 46, line 4
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MDRR (bps) : | MDRR (bps) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: MDRR (bps) | : MDRR (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 12 Data Item Type: 12
Length: 8 Length: 8
Maximum Data Rate (Receive): A 64-bit unsigned integer, representing Maximum Data Rate (Receive): A 64-bit unsigned integer, representing
the maximum theoretical data rate, in bits per second (bps), that the maximum theoretical data rate, in bits per second (bps), that
can be achieved while receiving on the link. can be achieved while receiving on the link.
11.13. Maximum Data Rate (Transmit) 10.13. Maximum Data Rate (Transmit)
The Maximum Data Rate (Transmit) (MDRT) data item MUST appear in the The Maximum Data Rate (Transmit) (MDRT) Data Item is used to indicate
Session Initialization Response message (Section 10.4), and MAY the maximum theoretical data rate, in bits per second, that can be
appear in the Session Update (Section 10.5), Destination Up
(Section 10.9), Destination Update (Section 10.15) and Link
Characteristics Response (Section 10.18) messages to indicate the
maximum theoretical data rate, in bits per second, that can be
achieved while transmitting data on the link. achieved while transmitting data on the link.
The Maximum Data Rate (Transmit) data item contains the following The Maximum Data Rate (Transmit) Data Item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MDRT (bps) : | MDRT (bps) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: MDRT (bps) | : MDRT (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 13 Data Item Type: 13
Length: 8 Length: 8
Maximum Data Rate (Transmit): A 64-bit unsigned integer, Maximum Data Rate (Transmit): A 64-bit unsigned integer,
representing the maximum theoretical data rate, in bits per second representing the maximum theoretical data rate, in bits per second
(bps), that can be achieved while transmitting on the link. (bps), that can be achieved while transmitting on the link.
11.14. Current Data Rate (Receive) 10.14. Current Data Rate (Receive)
The Current Data Rate (Receive) (CDRR) data item MUST appear in the The Current Data Rate (Receive) (CDRR) Data Item is used to indicate
Session Initialization Response message (Section 10.4), and MAY the rate at which the link is currently operating for receiving
appear in the Session Update (Section 10.5), Destination Up traffic.
(Section 10.9), Destination Update (Section 10.15) and Link
Characteristics Response (Section 10.18) messages to indicate the
rate at which the link is currently operating for receiving traffic.
When used in the Link Characteristics Request message When used in the Link Characteristics Request Message (Section 9.18),
(Section 10.17), CDRR represents the desired receive rate, in bits Current Data Rate (Receive) represents the desired receive rate, in
per second, on the link. bits per second, on the link.
The Current Data Rate (Receive) data item contains the following The Current Data Rate (Receive) Data Item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRR (bps) : | CDRR (bps) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: CDRR (bps) | : CDRR (bps) |
skipping to change at page 52, line 4 skipping to change at page 47, line 13
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRR (bps) : | CDRR (bps) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: CDRR (bps) | : CDRR (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 14 Data Item Type: 14
Length: 8 Length: 8
Current Data Rate (Receive): A 64-bit unsigned integer, representing Current Data Rate (Receive): A 64-bit unsigned integer, representing
the current data rate, in bits per second, that can currently be the current data rate, in bits per second, that can currently be
achieved while receiving traffic on the link. achieved while receiving traffic on the link.
If there is no distinction between current and maximum receive data If there is no distinction between current and maximum receive data
rates, current data rate receive MUST be set equal to the maximum rates, current data rate receive MUST be set equal to the maximum
data rate receive. data rate receive.
11.15. Current Data Rate (Transmit) 10.15. Current Data Rate (Transmit)
The Current Data Rate Transmit (CDRT) data item MUST appear in the The Current Data Rate (Transmit) (CDRT) Data Item is used to indicate
Session Initialization Response message (Section 10.4), and MAY the rate at which the link is currently operating for transmitting
appear in the Session Update (Section 10.5), Destination Up
(Section 10.9), Destination Update (Section 10.15), and Link
Characteristics Response (Section 10.18) messages to indicate the
rate at which the link is currently operating for transmitting
traffic. traffic.
When used in the Link Characteristics Request message When used in the Link Characteristics Request Message (Section 9.18),
(Section 10.17), CDRT represents the desired transmit rate, in bits Current Data Rate (Transmit) represents the desired transmit rate, in
per second, on the link. bits per second, on the link.
The Current Data Rate (Transmit) data item contains the following The Current Data Rate (Transmit) Data Item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRT (bps) : | CDRT (bps) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: CDRT (bps) | : CDRT (bps) |
skipping to change at page 53, line 5 skipping to change at page 48, line 9
Length: 8 Length: 8
Current Data Rate (Transmit): A 64-bit unsigned integer, Current Data Rate (Transmit): A 64-bit unsigned integer,
representing the current data rate, in bits per second, that can representing the current data rate, in bits per second, that can
currently be achieved while transmitting traffic on the link. currently be achieved while transmitting traffic on the link.
If there is no distinction between current and maximum transmit data If there is no distinction between current and maximum transmit data
rates, current data rate transmit MUST be set equal to the maximum rates, current data rate transmit MUST be set equal to the maximum
data rate transmit. data rate transmit.
11.16. Latency 10.16. Latency
The Latency data item MUST appear in the Session Initialization The Latency Data Item is used to indicate the amount of latency, in
Response message (Section 10.4), and MAY appear in the Session Update microseconds, on the link.
(Section 10.5), Destination Up (Section 10.9), Destination Update
(Section 10.15), and Link Characteristics Response (Section 10.18)
messages to indicate the amount of latency, in microseconds, on the
link.
When used in the Link Characteristics Request message The Latency value is reported as transmission delay. The calculation
(Section 10.17), Latency represents the maximum latency desired on of latency is implementation dependent. For example, the latency may
the link. be a running average calculated from the internal queuing.
The Latency value is reported as delay. The calculation of latency The Latency Data Item contains the following fields:
is implementation dependent. For example, the latency may be a
running average calculated from the internal queuing.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Latency : | Latency :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Latency | : Latency |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 16 Data Item Type: 16
Length: 8 Length: 8
Latency: A 64-bit unsigned integer, representing the transmission Latency: A 64-bit unsigned integer, representing the transmission
delay, in microseconds, that a packet encounters as it is delay, in microseconds, that a packet encounters as it is
transmitted over the link. transmitted over the link.
11.17. Resources (Receive) 10.17. Resources
The Resources (Receive) (RESR) data item MAY appear in the Session
Initialization Response message (Section 10.4), Session Update
(Section 10.5), Destination Up (Section 10.9), Destination Update
(Section 10.15) and Link Characteristics Response (Section 10.18)
messages to indicate the amount of resources for reception (with 0
meaning 'no resources available', and 100 meaning 'all resources
available') at the destination. The list of resources that might be
considered is beyond the scope of this document, and is left to
implementations to decide.
The Resources (Receive) data item contains the following fields:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESR |
+-+-+-+-+-+-+-+-+
Data Item Type: 17
Length: 1
Resources (Receive): An 8-bit integer percentage, 0-100,
representing the amount of resources allocated to receiving data.
Any value greater than 100 MUST be considered as invalid.
If a device cannot calculate RESR, this data item SHOULD NOT be The Resources (RES) Data Item is used to indicate the amount of
issued. finite resources available for data transmission and reception at the
destination as a percentage, with 0 meaning 'no resources remaining',
and 100 meaning 'a full supply', assuming that when Resources reaches
0 data transmission and/or reception will cease.
11.18. Resources (Transmit) An example of such resources might be battery life, but could equally
be magic beans. The list of resources that might be considered is
beyond the scope of this document, and is left to implementations to
decide.
The Resources (Transmit) (REST) data item MAY appear in the Session This Data Item is designed to be used as an indication of some
Initialization Response message (Section 10.4), Session Update capability of the modem and/or router at the destination.
(Section 10.5), Destination Up (Section 10.9), Destination Update
(Section 10.15) and Link Characteristics Response (Section 10.18)
messages to indicate the amount of resources for transmission (with 0
meaning 'no resources available', and 100 meaning 'all resources
available') at the destination. The list of resources that might be
considered is beyond the scope of this document, and is left to
implementations to decide.
The Resources (Transmit) data item contains the following fields: The Resources Data Item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| REST | | RES |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Data Item Type: 18 Data Item Type: 17
Length: 1 Length: 1
Resources (Transmit): An 8-bit integer percentage, 0-100, Resources: An 8-bit unsigned integer percentage, 0-100, representing
representing the amount of resources allocated to transmitting the amount of resources available. Any value greater than 100
data. Any value greater than 100 MUST be considered as invalid. MUST be considered as invalid.
If a device cannot calculate REST, this data item SHOULD NOT be If a device cannot calculate Resources, this Data Item SHOULD NOT be
issued. issued.
11.19. Relative Link Quality (Receive) 10.18. Relative Link Quality (Receive)
The Relative Link Quality (Receive) (RLQR) data item MAY appear in The Relative Link Quality (Receive) (RLQR) Data Item is used to
the Session Initialization Response message (Section 10.4), Session indicate the quality of the link to a destination for receiving
Update (Section 10.5), Destination Up (Section 10.9), Destination traffic as a percentage, with 0 meaning 'worst quality', and 100
Update (Section 10.15) and Link Characteristics Response meaning 'best quality'.
(Section 10.18) messages to indicate the quality of the link for
receiving data.
The Relative Link Quality (Receive) data item contains the following Quality in this context is defined as an indication of the stability
of a link for reception; a destination with high Relative Link
Quality (Receive) is expected to have generally stable DLEP metrics,
and the metrics of a destination with low Relative Link Quality
(Receive) can be expected to rapidly fluctuate over a wide range.
The Relative Link Quality (Receive) Data Item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RLQR | | RLQR |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Data Item Type: 19 Data Item Type: 18
Length: 1 Length: 1
Relative Link Quality (Receive): A non-dimensional unsigned 8-bit
integer, 0-100, representing relative quality of the link for
receiving traffic. Any value greater than 100 MUST be considered
as invalid.
Relative Link Quality (Receive): A non-dimensional 8-bit integer, If a device cannot calculate the Relative Link Quality (Receive),
0-100, representing relative link quality. A value of 100 this Data Item SHOULD NOT be issued.
represents a link of the highest quality. Any value greater than
100 MUST be considered as invalid.
If a device cannot calculate the RLQR, this data item SHOULD NOT be 10.19. Relative Link Quality (Transmit)
issued.
11.20. Relative Link Quality (Transmit) The Relative Link Quality (Transmit) (RLQT) Data Item is used to
indicate the quality of the link to a destination for transmitting
traffic as a percentage, with 0 meaning 'worst quality', and 100
meaning 'best quality'.
The Relative Link Quality (Transmit) (RLQT) data item MAY appear in Quality in this context is defined as an indication of the stability
the Session Initialization Response message (Section 10.4), Session of a link for transmission; a destination with high Relative Link
Update (Section 10.5), Destination Up (Section 10.9), Destination Quality (Transmit) is expected to have generally stable DLEP metrics,
Update (Section 10.15) and Link Characteristics Response and the metrics of a destination with low Relative Link Quality
(Section 10.18) messages to indicate the quality of the link for (Transmit) can be expected to rapidly fluctuate over a wide range.
transmitting data.
The Relative Link Quality (Transmit) data item contains the following The Relative Link Quality (Transmit) Data Item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RLQT | | RLQT |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Data Item Type: 20 Data Item Type: 19
Length: 1 Length: 1
Relative Link Quality (Transmit): A non-dimensional 8-bit integer, Relative Link Quality (Transmit): A non-dimensional unsigned 8-bit
0-100, representing relative link quality. A value of 100 integer, 0-100, representing relative quality of the link for
represents a link of the highest quality. Any value greater than transmitting traffic. Any value greater than 100 MUST be
100 MUST be considered as invalid. considered as invalid.
If a device cannot calculate the RLQT, this data item SHOULD NOT be If a device cannot calculate the Relative Link Quality (Transmit),
issued. this Data Item SHOULD NOT be issued.
11.21. Maximum Transmission Unit (MTU) 10.20. Maximum Transmission Unit (MTU)
The Maximum Transmission Unit (MTU) data item MAY appear in the The Maximum Transmission Unit (MTU) Data Item is used to indicate the
Session Initialization Response message (Section 10.4), Session maximum size, in octets, of an IP packet that can be transmitted
Update (Section 10.5), Destination Up (Section 10.9), Destination without fragmentation, including headers, but excluding any lower
Update (Section 10.15) and Link Characteristics Response layer headers.
(Section 10.18) messages to indicate the maximum size, in octets, of
an IP packet that can be transmitted without fragmentation, including
headers, but excluding any lower layer headers.
The Maximum Transmission Unit (MTU) data item contains the following The Maximum Transmission Unit Data Item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MTU | | MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 21 Data Item Type: 20
Length: 2 Length: 2
Maximum Transmission Unit (MTU): The maximum size, in octets, of an Maximum Transmission Unit: The maximum size, in octets, of an IP
IP packet that can be transmitted without fragmentation, including packet that can be transmitted without fragmentation, including
headers, but excluding any lower layer headers. headers, but excluding any lower layer headers.
If a device cannot calculate the MTU, this data item SHOULD NOT be If a device cannot calculate the Maximum Transmission Unit, this Data
issued. Item SHOULD NOT be issued.
12. Security Considerations 11. Security Considerations
The potential security concerns when using DLEP are: The potential security concerns when using DLEP are:
1. An attacker might pretend to be a DLEP peer, either at DLEP 1. An attacker might pretend to be a DLEP peer, either at DLEP
session initialization, or by injection of messages once a session initialization, or by injection of DLEP Messages once a
session has been established, and/or session has been established, and/or
2. DLEP data items could be altered by an attacker, causing the 2. DLEP Data Items could be altered by an attacker, causing the
receiving implementation to inappropriately alter its information receiving implementation to inappropriately alter its information
base concerning network status. base concerning network status.
Since DLEP is restricted to operation over a single (possibly Since DLEP is restricted to operation over a single (possibly
logical) hop at layer 2, implementations requiring authentication logical) hop at layer 2, implementations requiring authentication and
and/or encryption of traffic MUST take steps to secure the Layer 2 /or encryption of traffic MUST take steps to secure the Layer 2 link.
link. Examples of technologies that can be deployed to secure the Examples of technologies that can be deployed to secure the Layer 2
Layer 2 link include [IEEE-802.1AE] and [IEEE-802.1X]. link include [IEEE-802.1AE] and [IEEE-802.1X].
To avoid potential denial of service attack, it is RECOMMENDED that To avoid potential denial of service attack, it is RECOMMENDED that
implementations using the Peer Discovery mechanism maintain an implementations using the Peer Discovery mechanism maintain an
information base of hosts that persistently fail Session information base of hosts that persistently fail Session
Initialization having provided an acceptable Discovery signal, and Initialization having provided an acceptable Peer Discovery Signal,
ignore Peer Discovery signals from such hosts. and ignore subsequent Peer Discovery Signals from such hosts.
This specification does not address security of the data plane, as it This specification does not address security of the data plane, as it
(the data plane) is not affected, and standard security procedures (the data plane) is not affected, and standard security procedures
can be employed. can be employed.
13. IANA Considerations 12. IANA Considerations
This section specifies requests to IANA. This section specifies requests to IANA.
13.1. Registrations 12.1. Registrations
This specification defines: This specification defines:
o A new repository for DLEP signals and messages, with eighteen (18) o A new repository for DLEP Signals, with three (3) values currently
values currently assigned. assigned.
o Reservation of a Private Use numbering space within the above o Reservation of a Private Use numbering space within the above
repository for experimental DLEP signals and messages. repository for experimental DLEP Signals.
o A new repository for DLEP data items, with twenty-one (21) values o A new repository for DLEP Messages, with seventeen (17) values
currently assigned. currently assigned.
o Reservation of a Private Use numbering space within the data items o Reservation of a Private Use numbering space within the above
repository for experimental data items. repository for experimental DLEP Messages.
o A new repository for DLEP Data Items, with twenty one (21) values
currently assigned.
o Reservation of a Private Use numbering space within the Data Items
repository for experimental Data Items.
o A new repository for DLEP status codes, with eight (8) currently o A new repository for DLEP status codes, with eight (8) currently
assigned. assigned.
o Reservation of a Private Use numbering space within the status o Reservation of a Private Use numbering space within the status
codes repository for experimental status codes. codes repository for experimental status codes.
o A new repository for DLEP extensions, with one (1) value currently o A new repository for DLEP extensions, with one (1) value currently
assigned. assigned.
skipping to change at page 58, line 29 skipping to change at page 53, line 8
o A request for allocation of a well-known port for DLEP TCP and UDP o A request for allocation of a well-known port for DLEP TCP and UDP
communication. communication.
o A request for allocation of a link-local multicast IPv4 address o A request for allocation of a link-local multicast IPv4 address
for DLEP discovery. for DLEP discovery.
o A request for allocation of a link-local multicast IPv6 address o A request for allocation of a link-local multicast IPv6 address
for DLEP discovery. for DLEP discovery.
13.2. Signal/Message Type Registration 12.2. Signal Type Registration
A new repository must be created with the values of the DLEP signals A new repository must be created with the values of the DLEP Signals,
and messages, entitled "Message Type Values for the Dynamic Link entitled "Signal Type Values for the Dynamic Link Event Protocol
Event Protocol (DLEP)". The repository is to be managed using the (DLEP)". The repository is to be managed using the "Specification
Required" policy documented in [RFC5226].
All Signal values are in the range [0..65535], defined in Table 1.
12.3. Message Type Registration
A new repository must be created with the values of the DLEP
Messages, entitled "Message Type Values for the Dynamic Link Event
Protocol (DLEP)". The repository is to be managed using the
"Specification Required" policy documented in [RFC5226]. "Specification Required" policy documented in [RFC5226].
All signal and message values are in the range [0..65535], defined in All Message values are in the range [0..65535], defined in Table 2.
Table 1.
13.3. DLEP Data Item Registrations 12.4. DLEP Data Item Registrations
A new repository for DLEP data items must be created, entitled "Data A new repository for DLEP Data Items must be created, entitled "Data
Item Type Values for the Dynamic Link Event Protocol (DLEP)". The Item Type Values for the Dynamic Link Event Protocol (DLEP)". The
repository is to be managed using the "Specification Required" policy repository is to be managed using the "Specification Required" policy
documented in [RFC5226]. documented in [RFC5226].
All data item values are in the range [0..65535], defined in Table 2. All Data Item values are in the range [0..65535], defined in Table 3.
13.4. DLEP Status Code Registrations 12.5. DLEP Status Code Registrations
A new repository for DLEP status codes must be created, entitled A new repository for DLEP status codes must be created, entitled
"Status Code Values for the Dynamic Link Event Protocol (DLEP)". The "Status Code Values for the Dynamic Link Event Protocol (DLEP)". The
repository is to be managed using the "Specification Required" policy repository is to be managed using the "Specification Required" policy
documented in [RFC5226]. documented in [RFC5226].
All status codes are in the range [0..255], defined in Table 3. All status codes are in the range [0..255] , defined in Table 4.
13.5. DLEP Extensions Registrations With the exception of the reserved value 255, all status codes with
values >= 100 are marked as 'Continue' codes, others 'Terminate'.
12.6. DLEP Extensions Registrations
A new repository for DLEP extensions must be created, entitled A new repository for DLEP extensions must be created, entitled
"Extension Type Values for the Dynamic Link Event Protocol (DLEP)". "Extension Type Values for the Dynamic Link Event Protocol (DLEP)".
The repository is to be managed using the "Specification Required" The repository is to be managed using the "Specification Required"
policy documented in [RFC5226]. policy documented in [RFC5226].
All extension values are in the range [0..65535]. Current All extension values are in the range [0..65535]. Current
allocations are: allocations are:
+-------------+-----------------------------------------------------+ +--------------+----------------------------------------------+
| Code | Description | | Code | Description |
+-------------+-----------------------------------------------------+ +--------------+----------------------------------------------+
| 0 | Reserved | | 0 | Reserved |
| 1 | Credit Windowing | | 1 | Credit Windowing |
| 2-65519 | Unassigned. Available for future extensions | | 2-65519 | Unassigned. Available for future extensions |
| 65520-65534 | Private Use. Available for experiments | | 65520-65534 | Private Use. Available for experiments |
| 65535 | Reserved | | 65535 | Reserved |
+-------------+-----------------------------------------------------+ +--------------+----------------------------------------------+
Table 4: DLEP Extension types Table 5: DLEP Extension types
13.6. DLEP Well-known Port 12.7. DLEP Well-known Port
It is requested that IANA allocate a single well-known port number It is requested that IANA allocate a single well-known port number
for both TCP and UDP, for DLEP communication. SCTP port allocation for both TCP and UDP, for DLEP communication. SCTP port allocation
is not required. is not required.
13.7. DLEP IPv4 Link-local Multicast Address 12.8. DLEP IPv4 Link-local Multicast Address
It is requested that IANA allocate an IPv4 link-local multicast It is requested that IANA allocate an IPv4 link-local multicast
address for DLEP discovery signals. address for DLEP discovery Signals.
13.8. DLEP IPv6 Link-local Multicast Address 12.9. DLEP IPv6 Link-local Multicast Address
It is requested that IANA allocate an IPv6 link-local multicast It is requested that IANA allocate an IPv6 link-local multicast
address for DLEP discovery signals. address for DLEP discovery Signals.
14. Acknowledgements 13. Acknowledgements
We would like to acknowledge and thank the members of the DLEP design We would like to acknowledge and thank the members of the DLEP design
team, who have provided invaluable insight. The members of the team, who have provided invaluable insight. The members of the
design team are: Teco Boot, Bow-Nan Cheng, John Dowdell, and Henning design team are: Teco Boot, Bow-Nan Cheng, John Dowdell, and Henning
Rogge. Rogge.
We would also like to acknowledge the influence and contributions of We would also like to acknowledge the influence and contributions of
Greg Harrison, Chris Olsen, Martin Duke, Subir Das, Jaewon Kang, Greg Harrison, Chris Olsen, Martin Duke, Subir Das, Jaewon Kang,
Vikram Kaul, Nelson Powell, Lou Berger, and Victoria Mercieca. Vikram Kaul, Nelson Powell, Lou Berger, and Victoria Mercieca.
15. References 14. References
15.1. Normative References 14.1. Normative References
[CREDIT] Ratliff, S., "Credit Windowing extension for DLEP", draft- [CREDIT] Ratliff, S., "Credit Windowing extension for DLEP", IETF
ietf-manet-credit-window-00 IETF draft, October 2015. draft draft-ietf-manet-credit-window-02, March 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
DOI 10.17487/RFC2119, March 1997, RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
15.2. Informative References [UNIV8] , "The Unicode Consortium. The Unicode Standard, Version
8.0.0, (Mountain View, CA: The Unicode Consortium, 2015.
ISBN 978-1-936213-10-8)",
http://www.unicode.org/versions/Unicode8.0.0/, June 2015.
14.2. Informative References
[IEEE-802.1AE]
, "IEEE Standards for Local and Metropolitan Area
Networks: Media Access Control (MAC) Security", DOI
10.1109/IEEESTD.2006.245590, August 2006.
[IEEE-802.1X]
, "IEEE Standards for Local and Metropolitan Area
Networks: Port based Network Access Control", DOI 10.1109/
IEEESTD.2010.5409813, February 2010.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008, DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>. <http://www.rfc-editor.org/info/rfc5226>.
[RFC5578] Berry, B., Ed., Ratliff, S., Paradise, E., Kaiser, T., and [RFC5578] Berry, B., Ed., Ratliff, S., Paradise, E., Kaiser, T., and
M. Adams, "PPP over Ethernet (PPPoE) Extensions for Credit M. Adams, "PPP over Ethernet (PPPoE) Extensions for Credit
Flow and Link Metrics", RFC 5578, DOI 10.17487/RFC5578, Flow and Link Metrics", RFC 5578, DOI 10.17487/RFC5578,
February 2010, <http://www.rfc-editor.org/info/rfc5578>. February 2010, <http://www.rfc-editor.org/info/rfc5578>.
[IEEE-802.1AE]
IEEE Standards for Local and Metropolitan Area
Networks: Media Access Control (MAC) Security, July 2006
[IEEE-802.1X]
IEEE Standards for Local and Metropolitan Area
Networks: Port based Network Access Control, IEEE
P802.1x-2001, June 2001.
Appendix A. Discovery Signal Flows Appendix A. Discovery Signal Flows
Router Modem Signal Description
========================================================================
| Router initiates discovery, starts Router Modem Signal Description
| a timer, send Peer Discovery ========================================================================
|-------Peer Discovery---->|| signal.
~ ~ ~ ~ ~ ~ ~ Router discovery timer expires | Router initiates discovery, starts
without receiving Peer Offer. | a timer, send Peer Discovery
|-------Peer Discovery---->|| Signal.
| Router sends another Peer ~ ~ ~ ~ ~ ~ ~ Router discovery timer expires
|-------Peer Discovery---------->| Discovery signal. without receiving Peer Offer.
|
| Modem receives Peer Discovery | Router sends another Peer
| signal. |-------Peer Discovery---------->| Discovery Signal.
| |
| Modem sends Peer Offer with | Modem receives Peer Discovery
|<--------Peer Offer-------------| Connection Point information. | Signal.
: |
: Router MAY cancel discovery timer | Modem sends Peer Offer with
: and stop sending Peer Discovery |<--------Peer Offer-------------| Connection Point information.
: signals. :
: Router MAY cancel discovery timer
: and stop sending Peer Discovery
: Signals.
Appendix B. Peer Level Message Flows Appendix B. Peer Level Message Flows
B.1. Session Initialization B.1. Session Initialization
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
| Router connects to discovered or | Router connects to discovered or
| pre-configured Modem Connection | pre-configured Modem Connection
|---------TCP connect----------> Point. |---------TCP connect----------> Point.
| |
| Router sends Session | Router sends Session
|----Session Initialization----->| Initialization message. |----Session Initialization----->| Initialization Message.
| |
| Modem receives Session | Modem receives Session
| Initialization message. | Initialization Message.
| |
| Modem sends Session Initialization | Modem sends Session Initialization
|<--Session Initialization Resp.-| Response, with Success status data |<--Session Initialization Resp.-| Response, with Success Status Data
| | item. | | Item.
| | | |
|<<============================>>| Session established. Heartbeats |<<============================>>| Session established. Heartbeats
: : begin. : : begin.
B.2. Session Initialization - Refused B.2. Session Initialization - Refused
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
| Router connects to discovered or | Router connects to discovered or
| pre-configured Modem Connection | pre-configured Modem Connection
|---------TCP connect----------> Point. |---------TCP connect----------> Point.
| |
| Router sends Session | Router sends Session
|-----Session Initialization---->| Initialization message. |-----Session Initialization---->| Initialization Message.
| |
| Modem receives Session | Modem receives Session
| Initialization message, and will | Initialization Message, and will
| not support the advertised | not support the advertised
| extensions. | extensions.
| |
| Modem sends Session Initialization | Modem sends Session Initialization
| Response, with 'Request Denied' | Response, with 'Request Denied'
|<-Session Initialization Resp.--| status data item. |<-Session Initialization Resp.--| Status Data Item.
| |
| |
| Router receives negative Session | Router receives negative Session
| Initialization Response, closes | Initialization Response, closes
||---------TCP close------------|| TCP connection. ||---------TCP close------------|| TCP connection.
B.3. Router Changes IP Addresses B.3. Router Changes IP Addresses
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
| Router sends Session Update | Router sends Session Update
|-------Session Update---------->| message to announce change of IP |-------Session Update---------->| Message to announce change of IP
| address | address
| |
| Modem receives Session Update | Modem receives Session Update
| message and updates internal | Message and updates internal
| state. | state.
| |
|<----Session Update Response----| Modem sends Session Update |<----Session Update Response----| Modem sends Session Update
| Response. | Response.
B.4. Modem Changes Session-wide Metrics B.4. Modem Changes Session-wide Metrics
Router Modem Message Description
========================================================================
| Modem sends Session Update message Router Modem Message Description
| to announce change of modem-wide ========================================================================
|<--------Session Update---------| metrics
| | Modem sends Session Update Message
| Router receives Session Update | to announce change of modem-wide
| message and updates internal |<--------Session Update---------| metrics
| state. |
| | Router receives Session Update
|----Session Update Response---->| Router sends Session Update | Message and updates internal
| Response. | state.
|
|----Session Update Response---->| Router sends Session Update
| Response.
B.5. Router Terminates Session B.5. Router Terminates Session
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
| Router sends Session Termination | Router sends Session Termination
|------Session Termination------>| message with Status data item. |------Session Termination------>| Message with Status Data Item.
| | | |
|-------TCP shutdown (send)---> | Router stops sending messages. |-------TCP shutdown (send)---> | Router stops sending Messages.
| |
| Modem receives Session | Modem receives Session
| Termination, stops counting | Termination, stops counting
| received heartbeats and stops | received heartbeats and stops
| sending heartbeats. | sending heartbeats.
| |
| Modem sends Session Termination | Modem sends Session Termination
|<---Session Termination Resp.---| Response with Status 'Success'. |<---Session Termination Resp.---| Response with Status 'Success'.
| |
| Modem stops sending messages. | Modem stops sending Messages.
| |
||---------TCP close------------|| Session terminated. ||---------TCP close------------|| Session terminated.
B.6. Modem Terminates Session B.6. Modem Terminates Session
Router Modem Message Description
========================================================================
| Modem sends Session Termination Router Modem Message Description
|<----Session Termination--------| message with Status data item. ========================================================================
|
| Modem stops sending messages. | Modem sends Session Termination
| |<----Session Termination--------| Message with Status Data Item.
| Router receives Session |
| Termination, stops counting | Modem stops sending Messages.
| received heartbeats and stops |
| sending heartbeats. | Router receives Session
| | Termination, stops counting
| Router sends Session Termination | received heartbeats and stops
|---Session Termination Resp.--->| Response with Status 'Success'. | sending heartbeats.
| |
| Router stops sending messages. | Router sends Session Termination
| |---Session Termination Resp.--->| Response with Status 'Success'.
||---------TCP close------------|| Session terminated. |
| Router stops sending Messages.
|
||---------TCP close------------|| Session terminated.
B.7. Session Heartbeats B.7. Session Heartbeats
Router Modem Message Description
========================================================================
|----------Heartbeat------------>| Router sends heartbeat message Router Modem Message Description
| ========================================================================
| Modem resets heartbeats missed |----------Heartbeat------------>| Router sends heartbeat Message
| counter. |
| Modem resets heartbeats missed
| counter.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|---------[Any message]--------->| When the Modem receives any |---------[Any Message]--------->| When the Modem receives any
| message from the Router. | Message from the Router.
| |
| Modem resets heartbeats missed | Modem resets heartbeats missed
| counter. | counter.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|<---------Heartbeat-------------| Modem sends heartbeat message |<---------Heartbeat-------------| Modem sends heartbeat Message
| |
| Router resets heartbeats missed | Router resets heartbeats missed
| counter. | counter.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|<--------[Any message]----------| When the Router receives any |<--------[Any Message]----------| When the Router receives any
| message from the Modem. | Message from the Modem.
| |
| Modem resets heartbeats missed | Modem resets heartbeats missed
| counter. | counter.
B.8. Router Detects a Heartbeat timeout B.8. Router Detects a Heartbeat timeout
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
||<----------------------| Router misses a heartbeat ||<----------------------| Router misses a heartbeat
| ||<----------------------| Router misses too many heartbeats | ||<----------------------| Router misses too many heartbeats
| |
| |
|------Session Termination------>| Router sends Session Termination |------Session Termination------>| Router sends Session Termination
| message with 'Timeout' Status | Message with 'Timeout' Status
| data item. | Data Item.
: :
: Termination proceeds as above. : Termination proceeds as above.
B.9. Modem Detects a Heartbeat timeout B.9. Modem Detects a Heartbeat timeout
Router Modem Message Description
========================================================================
Router Modem Message Description |---------------------->|| Modem misses a heartbeat
========================================================================
|---------------------->|| Modem misses a heartbeat
|---------------------->|| | Modem misses too many heartbeats |---------------------->|| | Modem misses too many heartbeats
| |
| |
|<-----Session Termination-------| Modem sends Session Termination |<-----Session Termination-------| Modem sends Session Termination
| message with 'Timeout' Status | Message with 'Timeout' Status
| data item. | Data Item.
: :
: Termination proceeds as above. : Termination proceeds as above.
Appendix C. Destination Specific Message Flows Appendix C. Destination Specific Message Flows
C.1. Common Destination Notification C.1. Common Destination Notification
Router Modem Message Description
========================================================================
| Modem detects a new logical Router Modem Message Description
| destination is reachable, and ========================================================================
|<-------Destination Up----------| sends Destination Up message.
|
|------Destination Up Resp.----->| Router sends Destination Up
| Response.
~ ~ ~ ~ ~ ~ ~ | Modem detects a new logical
| Modem detects change in logical | destination is reachable, and
| destination metrics, and sends |<-------Destination Up----------| sends Destination Up Message.
|<-------Destination Update------| Destination Update message. |
|------Destination Up Resp.----->| Router sends Destination Up
| Response.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects change in logical | Modem detects change in logical
| destination metrics, and sends | destination metrics, and sends
|<-------Destination Update------| Destination Update message. |<-------Destination Update------| Destination Update Message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects logical destination | Modem detects change in logical
| is no longer reachable, and sends | destination metrics, and sends
|<-------Destination Down--------| Destination Down message. |<-------Destination Update------| Destination Update Message.
|
| Router receives Destination Down, ~ ~ ~ ~ ~ ~ ~
| updates internal state, and sends | Modem detects logical destination
|------Destination Down Resp.--->| Destination Down Response message. | is no longer reachable, and sends
|<-------Destination Down--------| Destination Down Message.
|
| Router receives Destination Down,
| updates internal state, and sends
|------Destination Down Resp.--->| Destination Down Response Message.
C.2. Multicast Destination Notification C.2. Multicast Destination Notification
Router Modem Message Description
========================================================================
| Router detects a new multicast Router Modem Message Description
| destination is in use, and sends ========================================================================
|--------Destination Up--------->| Destination Up message.
|
| Modem updates internal state to
| monitor multicast destination, and
|<-----Destination Up Resp.------| sends Destination Up Response.
~ ~ ~ ~ ~ ~ ~ | Router detects a new multicast
| Modem detects change in multicast | destination is in use, and sends
| destination metrics, and sends |-----Destination Announce------>| Destination Announce Message.
|<-------Destination Update------| Destination Update message. |
| Modem updates internal state to
| monitor multicast destination, and
|<-----Dest. Announce Resp.------| sends Destination Announce
Response.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects change in multicast | Modem detects change in multicast
| destination metrics, and sends | destination metrics, and sends
|<-------Destination Update------| Destination Update message. |<-------Destination Update------| Destination Update Message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Router detects multicast | Modem detects change in multicast
| destination is no longer in use, | destination metrics, and sends
|--------Destination Down------->| and sends Destination Down |<-------Destination Update------| Destination Update Message.
| message.
| ~ ~ ~ ~ ~ ~ ~
| Modem receives Destination Down, | Router detects multicast
| updates internal state, and sends | destination is no longer in use,
|<-----Destination Down Resp.----| Destination Down Response message. |--------Destination Down------->| and sends Destination Down
| Message.
|
| Modem receives Destination Down,
| updates internal state, and sends
|<-----Destination Down Resp.----| Destination Down Response Message.
C.3. Link Characteristics Request C.3. Link Characteristics Request
Router Modem Message Description
========================================================================
Destination has already been Router Modem Message Description
~ ~ ~ ~ ~ ~ ~ announced by either peer. ========================================================================
| Router requires different Destination has already been
| Characteristics for the ~ ~ ~ ~ ~ ~ ~ announced by either peer.
| destination, and sends Link
|--Link Characteristics Request->| Characteristics Request message. | Router requires different
| | Characteristics for the
| Modem attempts to adjust link | destination, and sends Link
| status to meet the received |--Link Characteristics Request->| Characteristics Request Message.
| request, and sends a Link |
| Characteristics Response | Modem attempts to adjust link
|<---Link Characteristics Resp.--| message with the new values. | properties to meet the received
| request, and sends a Link
| Characteristics Response
|<---Link Characteristics Resp.--| Message with the new values.
Authors' Addresses Authors' Addresses
Stan Ratliff Stan Ratliff
VT iDirect VT iDirect
13861 Sunrise Valley Drive, Suite 300 13861 Sunrise Valley Drive, Suite 300
Herndon, VA 20171 Herndon, VA 20171
USA USA
Email: sratliff@idirect.net Email: sratliff@idirect.net
Bo Berry
Shawn Jury Shawn Jury
Cisco Systems Cisco Systems
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
USA USA
Email: sjury@cisco.com Email: sjury@cisco.com
Darryl Satterwhite Darryl Satterwhite
Broadcom Broadcom
skipping to change at page 70, line 4 skipping to change at page 62, line 33
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
USA USA
Email: sjury@cisco.com Email: sjury@cisco.com
Darryl Satterwhite Darryl Satterwhite
Broadcom Broadcom
Email: dsatterw@broadcom.com Email: dsatterw@broadcom.com
Rick Taylor Rick Taylor
Airbus Defence & Space Airbus Defence & Space
Quadrant House Quadrant House
Celtic Springs Celtic Springs
Coedkernew Coedkernew
Newport NP10 8FZ Newport NP10 8FZ
UK UK
Email: rick.taylor@airbus.com Email: rick.taylor@airbus.com
Bo Berry
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