draft-ietf-manet-dlep-16.txt   draft-ietf-manet-dlep-17.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 B. Berry Intended status: Standards Track B. Berry
Expires: January 21, 2016 Expires: April 17, 2016
S. Jury S. Jury
Cisco Systems Cisco Systems
D. Satterwhite D. Satterwhite
Broadcom Broadcom
R. Taylor R. Taylor
Airbus Defence & Space Airbus Defence & Space
July 20, 2015 October 16, 2015
Dynamic Link Exchange Protocol (DLEP) Dynamic Link Exchange Protocol (DLEP)
draft-ietf-manet-dlep-16 draft-ietf-manet-dlep-17
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 January 21, 2016. This Internet-Draft will expire on April 17, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 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
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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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. Protocol Overview . . . . . . . . . . . . . . . . . . . . 7 1.1. Protocol Overview . . . . . . . . . . . . . . . . . . . . 7
1.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 8 1.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 8
2. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 8 2. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 8
3. Core Features and Extensions . . . . . . . . . . . . . . . . 10 3. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1. Experiments . . . . . . . . . . . . . . . . . . . . . . . 10 3.1. Mandatory Metrics . . . . . . . . . . . . . . . . . . . . 9
4. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4. DLEP Signal and Message Processing . . . . . . . . . . . . . 10
4.1. Mandatory Metrics . . . . . . . . . . . . . . . . . . . . 12 4.1. Transaction Model . . . . . . . . . . . . . . . . . . . . 11
5. DLEP Session Flow . . . . . . . . . . . . . . . . . . . . . . 12 5. DLEP Session Flow . . . . . . . . . . . . . . . . . . . . . . 11
5.1. Peer Discovery State . . . . . . . . . . . . . . . . . . 12 5.1. Peer Discovery State . . . . . . . . . . . . . . . . . . 12
5.2. Session Initialization State . . . . . . . . . . . . . . 13 5.2. Session Initialization State . . . . . . . . . . . . . . 13
5.3. In-Session State . . . . . . . . . . . . . . . . . . . . 14 5.3. In-Session State . . . . . . . . . . . . . . . . . . . . 14
5.4. Session Termination State . . . . . . . . . . . . . . . . 16 5.3.1. Heartbeats . . . . . . . . . . . . . . . . . . . . . 15
6. DLEP Signal and Message Processing . . . . . . . . . . . . . 16 5.4. Session Termination State . . . . . . . . . . . . . . . . 15
7. DLEP Signal and Message Structure . . . . . . . . . . . . . . 17 6. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 16
7.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 18 6.1. Experiments . . . . . . . . . . . . . . . . . . . . . . . 17
7.2. DLEP Message Header . . . . . . . . . . . . . . . . . . . 18 7. Scalability . . . . . . . . . . . . . . . . . . . . . . . . . 17
7.3. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 19 8. DLEP Signal and Message Structure . . . . . . . . . . . . . . 17
8. DLEP Signals and Messages . . . . . . . . . . . . . . . . . . 19 8.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 18
8.1. Peer Discovery Signal . . . . . . . . . . . . . . . . . . 20 8.2. DLEP Message Header . . . . . . . . . . . . . . . . . . . 19
8.2. Peer Offer Signal . . . . . . . . . . . . . . . . . . . . 21 8.3. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 19
8.3. Session Initialization Message . . . . . . . . . . . . . 21 9. DLEP Signals and Messages . . . . . . . . . . . . . . . . . . 20
8.4. Session Initialization Response Message . . . . . . . . . 22 9.1. Peer Discovery Signal . . . . . . . . . . . . . . . . . . 21
8.5. Session Update Message . . . . . . . . . . . . . . . . . 24 9.2. Peer Offer Signal . . . . . . . . . . . . . . . . . . . . 22
8.6. Session Update Response Message . . . . . . . . . . . . . 25 9.3. Session Initialization Message . . . . . . . . . . . . . 22
8.7. Session Termination Message . . . . . . . . . . . . . . . 25 9.4. Session Initialization Response Message . . . . . . . . . 23
8.8. Session Termination Response Message . . . . . . . . . . 26 9.5. Session Update Message . . . . . . . . . . . . . . . . . 25
8.9. Destination Up Message . . . . . . . . . . . . . . . . . 26 9.6. Session Update Response Message . . . . . . . . . . . . . 26
8.10. Destination Up Response Message . . . . . . . . . . . . . 27 9.7. Session Termination Message . . . . . . . . . . . . . . . 26
8.11. Destination Down Message . . . . . . . . . . . . . . . . 28 9.8. Session Termination Response Message . . . . . . . . . . 27
8.12. Destination Down Response Message . . . . . . . . . . . . 28 9.9. Destination Up Message . . . . . . . . . . . . . . . . . 27
8.13. Destination Update Message . . . . . . . . . . . . . . . 29 9.10. Destination Up Response Message . . . . . . . . . . . . . 28
8.14. Heartbeat Message . . . . . . . . . . . . . . . . . . . . 30 9.11. Destination Down Message . . . . . . . . . . . . . . . . 29
8.15. Link Characteristics Request Message . . . . . . . . . . 30 9.12. Destination Down Response Message . . . . . . . . . . . . 29
8.16. Link Characteristics Response Message . . . . . . . . . . 31 9.13. Destination Update Message . . . . . . . . . . . . . . . 30
9. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 32 9.14. Heartbeat Message . . . . . . . . . . . . . . . . . . . . 31
9.1. Status . . . . . . . . . . . . . . . . . . . . . . . . . 33 9.15. Link Characteristics Request Message . . . . . . . . . . 31
9.2. IPv4 Connection Point . . . . . . . . . . . . . . . . . . 35 9.16. Link Characteristics Response Message . . . . . . . . . . 32
9.3. IPv6 Connection Point . . . . . . . . . . . . . . . . . . 36 10. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 33
9.4. Peer Type . . . . . . . . . . . . . . . . . . . . . . . . 37 10.1. Status . . . . . . . . . . . . . . . . . . . . . . . . . 34
9.5. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 38 10.2. IPv4 Connection Point . . . . . . . . . . . . . . . . . 37
9.6. Extensions Supported . . . . . . . . . . . . . . . . . . 39 10.3. IPv6 Connection Point . . . . . . . . . . . . . . . . . 38
9.7. MAC Address . . . . . . . . . . . . . . . . . . . . . . . 39 10.4. Peer Type . . . . . . . . . . . . . . . . . . . . . . . 39
9.8. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 40 10.5. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 40
9.9. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 41 10.6. Extensions Supported . . . . . . . . . . . . . . . . . . 40
9.10. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 42 10.7. MAC Address . . . . . . . . . . . . . . . . . . . . . . 41
9.11. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 42 10.8. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 42
9.12. Maximum Data Rate (Receive) . . . . . . . . . . . . . . . 43 10.9. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 43
9.13. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 44 10.10. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 44
9.14. Current Data Rate (Receive) . . . . . . . . . . . . . . . 44 10.11. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 45
9.15. Current Data Rate (Transmit) . . . . . . . . . . . . . . 45 10.12. Maximum Data Rate (Receive) . . . . . . . . . . . . . . 46
9.16. Latency . . . . . . . . . . . . . . . . . . . . . . . . . 46 10.13. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 46
9.17. Resources (Receive) . . . . . . . . . . . . . . . . . . . 47 10.14. Current Data Rate (Receive) . . . . . . . . . . . . . . 47
9.18. Resources (Transmit) . . . . . . . . . . . . . . . . . . 47 10.15. Current Data Rate (Transmit) . . . . . . . . . . . . . . 48
9.19. Relative Link Quality (Receive) . . . . . . . . . . . . . 48 10.16. Latency . . . . . . . . . . . . . . . . . . . . . . . . 49
9.20. Relative Link Quality (Transmit) . . . . . . . . . . . . 49 10.17. Resources (Receive) . . . . . . . . . . . . . . . . . . 50
9.21. Link Characteristics Response Timer . . . . . . . . . . . 49 10.18. Resources (Transmit) . . . . . . . . . . . . . . . . . . 50
10. Credit-Windowing . . . . . . . . . . . . . . . . . . . . . . 50 10.19. Relative Link Quality (Receive) . . . . . . . . . . . . 51
10.1. Credit-Windowing Messages . . . . . . . . . . . . . . . 51 10.20. Relative Link Quality (Transmit) . . . . . . . . . . . . 52
10.1.1. Destination Up Message . . . . . . . . . . . . . . . 51 11. Security Considerations . . . . . . . . . . . . . . . . . . . 52
10.1.2. Destination Up Response Message . . . . . . . . . . 51 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 53
10.1.3. Destination Update Message . . . . . . . . . . . . . 51 12.1. Registrations . . . . . . . . . . . . . . . . . . . . . 53
10.2. Credit-Windowing Data Items . . . . . . . . . . . . . . 52 12.2. Expert Review: Evaluation Guidelines . . . . . . . . . . 54
10.2.1. Credit Grant . . . . . . . . . . . . . . . . . . . . 52 12.3. Signal/Message Type Registration . . . . . . . . . . . . 54
10.2.2. Credit Window Status . . . . . . . . . . . . . . . . 53 12.4. DLEP Data Item Registrations . . . . . . . . . . . . . . 54
10.2.3. Credit Request . . . . . . . . . . . . . . . . . . . 54 12.5. DLEP Status Code Registrations . . . . . . . . . . . . . 54
11. Security Considerations . . . . . . . . . . . . . . . . . . . 55 12.6. DLEP Extensions Registrations . . . . . . . . . . . . . 54
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 55 12.7. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 55
12.1. Registrations . . . . . . . . . . . . . . . . . . . . . 55 12.8. DLEP IPv6 Link-local Multicast Address . . . . . . . . . 55
12.2. Expert Review: Evaluation Guidelines . . . . . . . . . . 56 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 55
12.3. Signal/Message Type Registration . . . . . . . . . . . . 56 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 55
12.4. DLEP Data Item Registrations . . . . . . . . . . . . . . 56 14.1. Normative References . . . . . . . . . . . . . . . . . . 55
12.5. DLEP Status Code Registrations . . . . . . . . . . . . . 56 14.2. Informative References . . . . . . . . . . . . . . . . . 55
12.6. DLEP Extensions Registrations . . . . . . . . . . . . . 56 Appendix A. Discovery Signal Flows . . . . . . . . . . . . . . . 56
12.7. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 57 Appendix B. Peer Level Message Flows . . . . . . . . . . . . . . 56
12.8. DLEP Multicast Address . . . . . . . . . . . . . . . . . 57 B.1. Session Initialization . . . . . . . . . . . . . . . . . 56
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 57 B.2. Session Initialization - Refused . . . . . . . . . . . . 57
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 57 B.3. Router Changes IP Addresses . . . . . . . . . . . . . . . 57
14.1. Normative References . . . . . . . . . . . . . . . . . . 57 B.4. Modem Changes Session-wide Metrics . . . . . . . . . . . 57
14.2. Informative References . . . . . . . . . . . . . . . . . 57 B.5. Router Terminates Session . . . . . . . . . . . . . . . . 58
Appendix A. Discovery Signal Flows . . . . . . . . . . . . . . . 58 B.6. Modem Terminates Session . . . . . . . . . . . . . . . . 58
Appendix B. Peer Level Message Flows . . . . . . . . . . . . . . 58 B.7. Session Heartbeats . . . . . . . . . . . . . . . . . . . 59
B.1. Session Initialization . . . . . . . . . . . . . . . . . 58 B.8. Router Detects a Heartbeat timeout . . . . . . . . . . . 60
B.2. Session Initialization - Refused . . . . . . . . . . . . 59 B.9. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 61
B.3. Router Changes IP Addresses . . . . . . . . . . . . . . . 60 Appendix C. Destination Specific Signal Flows . . . . . . . . . 61
B.4. Modem Changes Session-wide Metrics . . . . . . . . . . . 60 C.1. Common Destination Signaling . . . . . . . . . . . . . . 61
B.5. Router Terminates Session . . . . . . . . . . . . . . . . 60 C.2. Multicast Destination Signaling . . . . . . . . . . . . . 62
B.6. Modem Terminates Session . . . . . . . . . . . . . . . . 61 C.3. Link Characteristics Request . . . . . . . . . . . . . . 62
B.7. Session Heartbeats . . . . . . . . . . . . . . . . . . . 61 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 63
B.8. Router Detects a Heartbeat timeout . . . . . . . . . . . 62
B.9. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 63
Appendix C. Destination Specific Signal Flows . . . . . . . . . 63
C.1. Common Destination Signaling . . . . . . . . . . . . . . 63
C.2. Multicast Destination Signaling . . . . . . . . . . . . . 64
C.3. Link Characteristics Request . . . . . . . . . . . . . . 64
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 65
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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As mentioned earlier, DLEP defines a set of messages used by modems As mentioned earlier, DLEP defines a set of messages used by modems
and their attached routers. The messages are used to communicate and their attached routers. The messages are used to communicate
events that occur on the physical link(s) managed by the modem: for events that occur on the physical link(s) managed by the modem: for
example, a remote node entering or leaving the network, or that the example, a remote node entering or leaving the network, or that the
link has changed. Associated with these messages are a set of data link has changed. Associated with these messages are a set of data
items - information that describes the remote node (e.g., address items - information that describes the remote node (e.g., address
information), and/or the characteristics of the link to the remote information), and/or the characteristics of the link to the remote
node. node.
The protocol is defined as a collection of type-length-value (TLV)
based formats, specifying the messages that are exchanged between a
router and a modem, and the data items associated with the message.
This document specifies transport of DLEP messages and data items via
the TCP transport, with a UDP-based discovery mechanism. Other
transports for the protocol are possible, but are outside the scope
of this document.
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. This router/modem sessions exist for each modem or connection. A router and modem form
session provides a carrier for information exchange concerning a session by completing the discovery and initialization process.
'destinations' that are available via the modem device. A This router-modem session persists unless or until it either (1)
'destination' can be either physical (as in the case of a specific times out, based on a heartbeat, or (2) is explicitly torn down by
far-end router), or a logical destination (as in a Multicast group). one of the participants.
As such, all of the destination-level exchanges in DLEP can be
envisioned as building an information base concerning the remote The router/modem session provides a carrier for information exchange
nodes, and the link characteristics to those nodes. concerning 'destinations' that are available via the modem device.
Destinations can be identified by either the router or the modem, and
represent a specific, addressable location (e.g., an address) that
can be reached via the link(s) managed by the modem. 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. As for a
logical destination, the best example is that of Multicast.
Multicast traffic destined for the variable-quality network (the Multicast traffic destined for the variable-quality network (the
network accessed via the DLEP modem) is handled in IP networks by network accessed via the DLEP modem) is handled in IP networks by
deriving a Layer 2 MAC address based on the Layer 3 address. deriving a Layer 2 MAC address based on the Layer 3 address.
Leveraging on this scheme, multicast traffic is supported in DLEP Leveraging on this scheme, multicast traffic is supported in DLEP
simply by treating the derived MAC address as any other 'destination' simply by treating the derived MAC address as any other destination
(albeit a logical one) in the network. To support these logical (albeit a logical one) in the network. To support these logical
destinations, one of the DLEP participants (typically, the router) destinations, one of the DLEP participants (typically, the router)
informs the other as to the existence of the logical destination. informs the other as to the existence of the logical destination.
The modem, once it is aware of the existence of this logical The modem, once it is aware of the existence of this logical
destination, reports link characteristics just as it would for any destination, reports link characteristics just as it would for any
other destination in the network. The specific algorithms a modem other destination in the network. The specific algorithms a modem
would use to derive metrics on multicast (or logical) destinations would use to derive metrics on multicast (or logical) destinations
are outside the scope of this specification, and is left to specific are outside the scope of this specification, and is left to specific
implementations to decide. implementations to decide.
The DLEP messages concerning destinations thus become the way for
routers and modems to maintain, and notify each other about, an
information base representing the physical and logical (e.g.,
multicast) destinations accessible via the modem device, as well as
the link characteristics to those destinations.
1.2. Requirements 1.2. 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].
2. Assumptions 2. Assumptions
Routers and modems that exist as part of the same node (e.g., that DLEP specifies UDP multicast for single-hop discovery signalling, and
are locally connected) can use a discovery technique to locate each TCP for transport of the control messages. Therefore, DLEP assumes
other, thus avoiding a priori configuration. The router is that the modem and router have topologically consistent IP addresses
responsible for initializing the discovery process, using the Peer
Discovery signal (Section 8.1).
DLEP uses a session-oriented paradigm. A router and modem form a
session by completing the discovery and initialization process. This
router-modem session persists unless or until it either (1) times
out, based on the timeout values supplied, or (2) is explicitly torn
down by one of the participants. Note that while use of timers in
DLEP is optional, it is strongly RECOMMENDED that implementations
choose to run with timers enabled.
DLEP assumes that the MAC address for delivering data traffic is the
MAC specified in the Destination Up message (Section 8.9). No
manipulation or substitution is performed; the MAC address supplied
in Destination Up is used as the OSI Layer 2 Destination MAC address.
DLEP also assumes that MAC addresses MUST be unique within the
context of a router-modem session. Additionally, 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).
DLEP uses UDP multicast for single-hop discovery signalling, and TCP
for transport of the control messages. Therefore, DLEP assumes that
the modem and router have topologically consistent IP addresses
assigned. It is RECOMMENDED that DLEP implementations utilize IPv6 assigned. It is RECOMMENDED that DLEP implementations utilize IPv6
link-local addresses to reduce the administrative burden of address link-local addresses to reduce the administrative burden of address
assignment. assignment. Other reliable transports for the protocol are possible,
but are outside the scope of this document.
Destinations can be identified by either the router or the modem, and
represent a specific destination (e.g., an address) that exists on
the link(s) managed by the modem. A destination MUST contain a MAC
address, it MAY optionally include a Layer 3 address (or addresses).
Note that since a destination is a MAC address, the MAC could
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 on
destinations accessible via the modem.
The DLEP messages concerning destinations thus become the way for
routers and modems to maintain, and notify each other about, an
information base representing the physical and logical (e.g.,
multicast) destinations accessible via the modem device. The
information base would contain addressing information (i.e. MAC
address, and OPTIONALLY, Layer 3 addresses), link characteristics
(metrics), and OPTIONALLY, flow control information (credits).
DLEP assumes that any message not understood by a receiver MUST DLEP assumes that the MAC address for delivering data traffic is the
result in an error indication being sent to the originator, and also MAC address used by DLEP to identify the destination. No
MUST result in termination of the session between the DLEP peers. manipulation or substitution is performed; the MAC address supplied
Any DLEP data item not understood by a receiver MUST also result in in a Destination Up message (Section 9.9) message is used as the OSI
termination of the session. Layer 2 Destination MAC address. DLEP also assumes that MAC
addresses are unique within the context of a router-modem session.
DLEP assumes that security on the session (e.g., authentication of DLEP assumes that security on the session (e.g., authentication of
session partners, encryption of traffic, or both) is dealt with by session partners, encryption of traffic, or both) is dealt with by
the underlying transport mechanism (e.g., by using a transport such the underlying transport mechanism (e.g., by using a transport such
as TLS [RFC5246]). as TLS [RFC5246]).
This document specifies an implementation of the DLEP messages 3. Metrics
running over the TCP transport. It is assumed that DLEP running over
other transport mechanisms would be documented separately.
3. Core Features and Extensions
DLEP has a core set of signals, messages and data items that MUST be
parsed without error by an implementation in order to guarantee
interoperability and therefore make the implementation DLEP
compliant. This document defines this set of signals, messages and
data items, listing them as 'core'. It should be noted that some
core signals, messages and data items might not be used during the
lifetime of a single DLEP session, but a compliant implementation
MUST support them.
While this document represents the best efforts of the working group
to be functionally complete, it is recognized that extensions to DLEP
will in all likelihood be necessary as more link types are used.
If interoperable protocol extensions are required, they MUST be
standardized either as an update to this document, or as an
additional stand-alone specification. The requests for IANA-
controlled registries in this document contain sufficient Reserved
space, in terms of DLEP signals, messages, data items and status
codes, to accommodate future extensions to the protocol and the data
transferred.
All extensions are considered OPTIONAL. Extensions may be negotiated
on a per-session basis during session initialization via the
Extensions Supported mechanism. Only the DLEP functionality listed
as 'core' is required by an implementation in order to be DLEP
compliant.
This specification defines one extension, Credit Windowing, that
devices MAY choose to implement.
3.1. Experiments
This document requests Private Use numbering space in the DLEP
signal/message, data item and status code registries for experimental
items. The intent is to allow for experimentation with new signals,
messages, data items, and/or status codes, while still retaining the
documented DLEP behavior.
Use of the experimental signals, messages, data items, status codes,
or behaviors MUST be announced as Extensions, using extension
identifiers from the Private Use space in the Extensions Supported
registry (Table 4), during session initialization with a value agreed
upon (a priori) between the participating peers.
Multiple experiments MAY be announced in the Session Initialization
messages. However, use of multiple experiments in a single session
could lead to interoperability issues or unexpected results (e.g.,
clashes of experimental signals, messages, data items and/or status
code types), and is therefore discouraged. It is left to
implementations to determine the correct processing path (e.g., a
decision on whether to terminate the session, or to establish a
precedence of the conflicting definitions) if such conflicts arise.
4. 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 with a 'best effort', incorporating all metrics have been calculated with 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 receiver MUST propagate the metrics to all entries in its level, the receiver MUST propagate the metrics to all entries in its
information base for destinations that are accessed via the information base for destinations that are accessed via the
originator. originator.
DLEP modem implementations MUST announce all metric items that will
be reported during the session, and provide default values for those
metrics, in the Session Initialization Response message
(Section 8.4). In order to use a metric type that was not included
in the Session Initialization Response message, modem implementations
MUST terminate the session with the router (via the Session Terminate
message (Section 8.7)), and establish a new session.
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 modem-wide basis, if all
connections via the modem are of this static nature). connections via the modem are of this static nature).
DLEP modem implementations MUST announce all metric items that will
be reported during the session, and provide default values for those
metrics, in the Session Initialization Response message
(Section 9.4). In order to use a metric type that was not included
in the Session Initialization Response message, modem implementations
MUST terminate the session with the router (via the Session Terminate
message (Section 9.7)), and establish a new session.
A DLEP participant MAY send metrics both in a session context (via A DLEP participant MAY send metrics both in a session context (via
the Session Update message) and a specific destination context (via the Session Update message) and a specific destination context (via
Destination Update) at any time. The heuristics for applying Destination Update) at any time. The most recently received metric
received metrics is left to implementations. value MUST take precedence over any earlier value, regardless of
context - that is: 1. If the receiver gets metrics in a specific
destination context (via Destination Update), then the specific
destination is updated with the new metric. 2. If the receiver gets
metrics in a modem-wide context (via Peer Update), then the received
metrics for all destinations accessed via the modem MUST be updated
to the newly received value.
4.1. Mandatory Metrics 3.1. Mandatory Metrics
As mentioned above, DLEP modem implementations MUST announce all As mentioned above, DLEP modem implementations MUST announce all
supported metric items during the Session Initialization state. supported metric items during the Session Initialization state.
However, a modem MUST include the following list of metrics in the However, a modem MUST include the following list of metrics in the
Session Initialization Response message (Section 8.4): Session Initialization Response message (Section 9.4):
o Maximum Data Rate (Receive) (Section 9.12) o Maximum Data Rate (Receive) (Section 10.12)
o Maximum Data Rate (Transmit) (Section 9.13) o Maximum Data Rate (Transmit) (Section 10.13)
o Current Data Rate (Receive) (Section 9.14) o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Transmit) (Section 9.15) o Current Data Rate (Transmit) (Section 10.15)
o Latency (Section 9.16) o Latency (Section 10.16)
4. DLEP Signal and Message Processing
Most messages in DLEP are members of a request/response pair, e.g.
Destination Up message (Section 9.9), and Destination Up Response
message (Section 9.10). As mentioned before, session message pairs
control the flow of the session through the various states, e.g. an
implementation MUST NOT leave the Session Initialization state until
a Session Initialization message (Section 9.3) and Session
Initialization Response message (Section 9.4) have been exchanged.
Destination message pairs describe the arrival and departure of
logical 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 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).
Prior to the exchange of a pair of Destination Up and Destination Up
Response messages, no messages concerning the logical destination
identified by the MAC Address data item (Section 10.7) may be sent.
An implementation receiving a message with such an unannounced
destination MUST terminate the session by issuing a Session
Termination message (Section 9.7) with a status code of 'Invalid
Destination', see Table 3, and transition to the Session Termination
state.
The receiver of a Destination Up message MAY decline further messages
concerning a given destination by sending a Destination Up Response
with a status code of 'Not Interested', see Table 3. Receivers of
such responses MUST NOT send further messages concerning that
destination to the peer.
After exchanging a pair of Destination Down (Section 9.11) and
Destination Down Response (Section 9.12) messages, no messages
concerning the logical destination identified by the MAC Address data
item may be a sent without a previously sending a new Destination Up
message. An implementation 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.
4.1. Transaction Model
DLEP defines a simple message transaction model: Only one (1) request
per destination may be in progress at a time. A message transaction
is considered complete when a response matching a previously issued
request is received. If a peer receives a request for a destination
for which there is already an outstanding request, the peer MUST
terminate the session by issuing a Session Termination message
(Section 9.7) with a status code of 'Unexpected Message', see
Table 3, 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 refers to a different
destination.
It should be noted that some requests may take a considerable amount
of time for some peers to complete, for example a modem handling a
multicast destination up request may have to perform a complex
network reconfiguration. A sending implementation MUST be able to
handle such long running transactions gracefully.
Additionally, only one (1) session request, e.g. a Session
Initialization message (Section 9.3) may be in progress at a time.
As above, a session transaction is considered complete when a
response matching a previously issued request is received. If a peer
receives a session request while there is already a session request
in progress, the peer MUST terminate the session by issuing a Session
Termination message with a status code of 'Unexpected Message', and
transition to the Session Termination state. Only the Session
Termination message may be issued when a session transaction is in
progress. Heartbeat messages (Section 9.14) MUST NOT be considered
part of a session transaction.
DLEP transactions do not time out and are not cancellable. An
implementation can detect if a peer has failed in some way by use of
the session heartbeat mechanism during the In-Session state, see
Section 5.3.
5. DLEP Session Flow 5. DLEP Session Flow
All DLEP peers transition through four (4) distinct states during the All DLEP peers transition through four (4) distinct states during the
lifetime of a DLEP session: 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
The Peer Discovery state is OPTIONAL to implement for routers. If it The Peer Discovery state is OPTIONAL to implement for routers. If it
is used, this state is the initial state. If it is not used, then is used, this state is the initial state. If it is not used, then
one or more preconfigured address/port combinations SHOULD be one or more preconfigured address/port combinations SHOULD be
provided to the router, and the device starts in the Session provided to the router, and the device starts in the Session
Initialization state. Initialization state.
skipping to change at page 12, line 50 skipping to change at page 12, line 18
The Peer Discovery state is OPTIONAL to implement for routers. If it The Peer Discovery state is OPTIONAL to implement for routers. If it
is used, this state is the initial state. If it is not used, then is used, this state is the initial state. If it is not used, then
one or more preconfigured address/port combinations SHOULD be one or more preconfigured address/port combinations SHOULD be
provided to the router, and the device starts in the Session provided to the router, and the device starts in the Session
Initialization state. Initialization state.
Modems MUST support the Peer Discovery state. Modems MUST support the Peer Discovery state.
5.1. Peer Discovery State 5.1. Peer Discovery State
In the Peer Discovery state, routers send UDP packets containing a In the Peer Discovery state, routers MUST send UDP packets containing
Peer Discovery signal (Section 8.1) to the DLEP well-known multicast a Peer Discovery signal (Section 9.1) to the DLEP well-known IPv6
address (Section 12.8) and port number (Section 12.7) then await a link-local multicast address (Section 12.8) and port number
unicast UDP packet containing a Peer Offer signal (Section 8.2) from (Section 12.7), setting the packet source address to a valid local
a modem. While in the Peer Discovery state, Peer Discovery signals IPv6 address and the source port to an unused port in the range 49152
MUST be sent repeatedly by a router, at regular intervals; every to 65535. If the router implementation supports IPv4, then they MAY
three (3) seconds is RECOMMENDED. also broadcast Peer Discovery signals in UDP packets to the IPv4
broadcast address (255.255.255.255), setting the packet source
address to a valid local IPv4 address and the source port to an
unused port in the range 49152 to 65535.
The implementation then waits for a unicast UDP packet containing a
Peer Offer signal (Section 9.2) from a potential peer modem. While
in the Peer Discovery state, Peer Discovery signals MUST be sent
repeatedly by a router, at regular intervals; every three (3) seconds
with some jitter is RECOMMENDED.
In the Peer Discovery state, the modem waits for incoming Peer In the Peer Discovery state, the modem waits for incoming Peer
Discovery signals on the DLEP well-known multicast address and port. Discovery signals on the DLEP well-known multicast address and port.
On receipt of a valid signal, it MUST unicast a Peer Offer signal to On receipt of a valid signal, it MUST unicast a Peer Offer signal to
the source address of the received UDP packet. Peer Offer signals the source address and port of the received UDP packet. Peer Offer
MAY contain the unicast address and port for TCP-based communication signals MAY contain the unicast address and port for TCP-based
with a modem, via the IPv4 Connection Point data item (Section 9.2) communication with a modem, via the IPv4 Connection Point data item
or the IPv6 Connection Point data item (Section 9.3), on which it is (Section 10.2) or the IPv6 Connection Point data item (Section 10.3),
prepared to accept an incoming TCP connection. The modem then begins on which it is prepared to accept an incoming TCP connection. If the
listening for incoming TCP connections, and, having accepted one, modem does not include an IPv4 Connection Point data item, nor a IPv6
enters the Session Initialization state. Anything other than Peer Connection Point data item, then the source address of the packet
Discovery signals received on the UDP socket MUST be silently containing the Peer Offer signal MUST be set to the address on which
dropped. the modem is willing to accept TCP connections.
The modem then begins listening for incoming TCP connections, and,
having accepted one, enters the Session Initialization state.
Anything other than Peer Discovery signals received on the UDP socket
MUST be silently dropped.
Modems SHOULD be prepared to accept a TCP connection from a router Modems SHOULD be prepared to accept a TCP connection from a router
that is not using the Discovery mechanism, i.e. a connection attempt that is not using the Discovery mechanism, i.e. a connection attempt
that occurs without a preceeding Peer Discovery signal. The modem that occurs without a preceding Peer Discovery signal. The modem
MUST accept a TCP connection on only one (1) address/port combination MUST accept a TCP connection on only one (1) address/port combination
per session. per 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. If a TCP connection cannot be achieved using any of the tried. It is RECOMMENDED that an implementation attempt to connect
address/port combinations and the Discovery mechanism is in use, then to any announced IPv6 address/port combinations before attempting to
the router SHOULD resume issuing Peer Discovery signals. If no IP use IPv4 combinations. If a TCP connection cannot be achieved using
Connection Point data items are included in the Peer Offer signal, any of the address/port combinations and the Discovery mechanism is
the router MUST use the origin address of the signal as the IP in use, then the router SHOULD resume issuing Peer Discovery signals.
If no IPv4 Connection Point data items, nor IPv6 Connection Point
data items are included in the Peer Offer signal, the router MUST use
the origin address of the UDP packet containing the signal as the IP
address, and the DLEP well-known port number. address, and the DLEP well-known port number.
Once a TCP connection has been established with the modem, the router Once a TCP connection has been established with the modem, the router
begins a new session and enters the Session Initialization state. It begins a new session and enters the Session Initialization state. It
is up to the router implementation if Peer Discovery signals continue is up to the router implementation if Peer Discovery signals continue
to be sent after the device has transitioned to the Session to be sent after the device has transitioned to the Session
Initialization state. Initialization state.
It should be noted that the peer discovery process operates using
link-local multicast and is hence inapplicable if the potential peers
are separated by more than one hop.
5.2. Session Initialization State 5.2. 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 8.3) to the modem. The Session Initialization message (Section 9.3) 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 8.4) from the modem. Receipt of the Response message (Section 9.4) 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 9.1) with value 'Success', see Table 3, indicates that the (Section 10.1) with value 'Success', see Table 3, indicates that the
modem has received and processed the Session Initialization message, modem has received and processed the Session Initialization message,
and the router MUST transition to the In-Session state. 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 and successful parsing of a Session Initialization message, receipt and successful parsing of a Session Initialization message,
the modem MUST send a Session Initialization Response message, and the modem MUST send a Session Initialization Response message, and
the session MUST transition to the In-Session state. the session MUST transition to the In-Session state.
As mentioned before, DLEP provides an extension negotiation DLEP provides an extension negotiation capability to be used in the
capability to be used in the Session Initialization state. Session Initialization state, see Section 6. Extensions supported by
Extensions supported by an implementation MUST be declared to an implementation MUST be declared to potential DLEP peers using the
potential DLEP peers using the Extensions Supported data item Extensions Supported data item (Section 10.6). Once both peers have
(Section 9.6). exchanged initialization messages, an implementation MUST NOT emit
any message, signal, data item or status code associated with an
Once both peers have exchanged initialization messages, an extension that was not specified in the received initialization
implementation MUST NOT emit any message, signal, data item or status message from its peer.
code associated with an extension that was not specified in the
received initialization message from its peer.
If the router receives any message other than a valid Session If the router receives any message other than a valid Session
Initialization Response, it MUST send a Session Termination message Initialization Response, it MUST send a Session Termination message
(Section 8.7) with a relevant status code, e.g. 'Unexpected (Section 9.7) with a relevant status code, e.g. 'Unexpected
Message', see Table 3, and transition to the Session Termination Message', see Table 3, and transition to the Session Termination
state. state.
If the modem receives any message other than Session Initialization, If the modem receives any message other than Session Initialization,
or it fails to parse the received message, it MUST NOT send any or it fails to parse the received message, it MUST NOT send any
message, and MUST terminate the TCP connection, then restart at the message, and MUST terminate the TCP connection, then restart at the
Peer Discovery state. Peer Discovery state.
As mentioned before, the Session Initialization Response message MUST As mentioned before, the Session Initialization Response message MUST
contain metric data items for ALL metrics that will be used during contain metric data items for all metrics that will be used during
the session. If an additional metric is to be introduced after the the session. If an additional metric is to be introduced after the
session has started, the session between router and modem MUST be session has started, the session between router and modem MUST be
terminated and restarted, and the new metric described in the next terminated and restarted, and the new metric described in the next
Session Initialization Response message. Session Initialization Response message.
5.3. In-Session State 5.3. 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
peers, indicating changes to the session state, the arrival or 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.
In order to maintain the In-Session state, periodic Heartbeat
messages (Section 8.14) MAY be exchanged between router and modem.
These messages are intended to keep the session alive, and to verify
bidirectional connectivity between the two participants. Each DLEP
peer is responsible for the creation of heartbeat messages. Receipt
of any valid DLEP message MUST reset the heartbeat interval timer
(i.e., valid DLEP messages take the place of, and obviate the need
for, Heartbeat messages).
DLEP provides a Session Update message (Section 8.5), intended to
communicate some change in status (e.g., a change of layer 3 address
parameters, or a modem-wide link change).
In addition to the session messages, the participants will transmit In addition to the session messages, the participants will transmit
messages concerning destinations in the network. These messages messages concerning destinations in the network. These messages
trigger creation/maintenance/deletion of destinations in the trigger creation/maintenance/deletion of destinations in the
information base of the recipient. For example, a modem will inform information base of the recipient. For example, a modem will inform
its attached router of the presence of a new destination via the its attached router of the presence of a new destination via the
Destination Up message (Section 8.9). Receipt of a Destination Up Destination Up message (Section 9.9). Receipt of a Destination Up
causes the router to allocate the necessary resources, creating an causes the router to allocate the necessary resources, creating an
entry in the information base with the specifics (i.e. MAC Address, entry in the information base with the specifics (i.e. MAC Address,
Latency, Data Rate, etc.) of the destination. The loss of a Latency, Data Rate, etc.) of the destination. The loss of a
destination is communicated via the Destination Down message destination is communicated via the Destination Down message
(Section 8.11), and changes in status to the destination (e.g., (Section 9.11), and changes in status to the destination (e.g.,
varying link quality, or addressing changes) are communicated via the varying link quality, or addressing changes) are communicated via the
Destination Update message (Section 8.13). The information on a Destination Update message (Section 9.13). The information on a
given destination will persist in the router's information base until given destination will persist in the router's information base until
(1) a Destination Down message is received, indicating that the modem (1) a Destination Down message is received, indicating that the modem
has lost contact with the remote node, or (2) the router/modem has lost contact with the remote node, or (2) the router/modem
transitions to the Session Termination state. transitions to the Session Termination state.
In addition to receiving metrics about the link, DLEP provides a As well as receiving metrics about the link, DLEP provides a message
message allowing a router to request a different datarate, or allowing a router to request a different datarate or latency from the
latency, from the modem. This message is referred to as the Link modem. This message is the Link Characteristics Request message
Characteristics Request message (Section 8.15), and gives the router (Section 9.15), and gives the router the ability to deal with
the ability to deal with requisite increases (or decreases) of requisite increases (or decreases) of allocated datarate/latency in
allocated datarate/latency in demand-based schemes in a more demand-based schemes in a more deterministic manner.
deterministic manner.
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 The implementation terminates the session by sending a Session o The implementation terminates the session by sending a Session
Termination message (Section 8.7)), or Termination message (Section 9.7)), or
o The DLEP peer terminates the session, indicated by receiving a o The peer terminates the session, indicated by receiving a Session
Session termination message. Termination message.
The implementation MUST then transition to the Session Termination The implementation MUST then transition to the Session Termination
state. state.
5.3.1. Heartbeats
In order to maintain the In-Session state, periodic Heartbeat
messages (Section 9.14) MAY be exchanged between router and modem.
These messages are intended to keep the session alive, and to verify
bidirectional connectivity between the two participants. Each DLEP
peer is responsible for the creation of heartbeat messages. Receipt
of any valid DLEP message MUST reset the heartbeat interval timer
(i.e., valid DLEP messages take the place of, and obviate the need
for, additional Heartbeat messages).
Implementations SHOULD allow two (2) heartbeat intervals to expire
with no traffic on the router/modem session before terminating the
session by issuing a Session Termination message with a status code
of 'Timed Out', and then transition to the Session Termination state.
5.4. Session Termination State 5.4. Session Termination State
When a DLEP implementation enters the Session Termination state after When a DLEP implementation enters the Session Termination state after
sending a Session Termination message (Section 8.7) as the result of sending a Session Termination message (Section 9.7) 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 8.8) from its peer. If Heartbeat messages Response message (Section 9.8) from its peer. If Heartbeat messages
(Section 8.14) are in use, senders SHOULD allow four (4) heartbeat (Section 9.14) are in use, senders SHOULD allow four (4) heartbeat
intervals to expire before assuming that the peer is unresponsive, intervals to expire before assuming that the peer is unresponsive,
and continuing with session termination. If Heartbeat messages are and continuing with session termination. If Heartbeat messages are
not in use, then if is RECOMMENDED that an interval of eight (8) not in use, then if is RECOMMENDED that an interval of eight (8)
seconds be used. seconds be used.
When a DLEP implementation enters the Session Termination state When an implementation enters the Session Termination state having
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. immediately send a Session Termination Response.
The sender and receiver of a Session Termination message MUST release The sender and receiver of a Session Termination message MUST release
all resources allocated for the session, and MUST eliminate all all resources allocated for the session, and MUST eliminate all
destinations in the information base accessible via the peer destinations in the information base accessible via the peer
represented by the session. No Destination Down messages represented by the session. Destination Down messages (Section 9.11)
(Section 8.11) are sent. MUST NOT be sent.
Any messages received after either sending or receiving a Session Any messages received after either sending or receiving a Session
Termination message MUST be silently ignored. Termination message MUST be silently ignored.
Once Session Termination messages have been exchanged, or timed out, Once Session Termination messages have been exchanged, or timed out,
the device MUST terminate the TCP connection to the peer, and return the device MUST terminate the TCP connection to the peer, and return
to the relevant initial state. to the relevant initial state.
6. DLEP Signal and Message Processing 6. Extensions
Most messages in DLEP are members of a request/response pair, e.g. While this document represents the best efforts of the working group
Destination Up message (Section 8.9), and Destination Up Response to be functionally complete, it is recognized that extensions to DLEP
message (Section 8.10). These pairs of messages define an implicit will in all likelihood be necessary as more link types are used.
transaction model for both session messages and destination messages. Such extensions are defined as additional rules of behaviour,
messages, data items and/or status codes that are not defined in this
document.
As mentioned before, session message pairs control the flow of the Extensions MUST be negotiated on a per-session basis during session
session through the various states, e.g. an implementation MUST NOT initialization via the Extensions Supported mechanism.
leave the Session Initialization state until a Session Initialization Implementations are not required to support any extension in order to
message (Section 8.3) and Session Initialization Response message be considered DLEP compliant. An extension document, describing the
(Section 8.4) have been exchanged. operation of a credit windowing scheme for flow control, is described
in [CREDIT].
Destination message pairs describe the arrival and departure of If interoperable protocol extensions are required, they MUST be
logical destinations, and control the flow of information about the standardized either as an update to this document, or as an
destinations in the several ways. additional stand-alone specification. The requests for IANA-
controlled registries in this document contain sufficient Reserved
space for DLEP signals, messages, data items and status codes to
accommodate future extensions to the protocol.
Prior to the exchange of a pair of Destination Up and Destination Up As multiple protocol extensions MAY be announced during session
Response messages, no messages concerning the logical destination initialization, authors of protocol extensions MUST consider the
identified by the MAC Address data item (Section 9.7) may be sent. interaction of their extension with other published extensions, and
An implementation receiving a message with such an unannounced specify any incompatibilities.
destination MUST terminate the session by issuing a Session
Termination message (Section 8.7) with a status code of 'Invalid
Destination', see Table 3, and transition to the Session Termination
state.
The receiver of a Destination Up message MAY decline further messages 6.1. Experiments
concerning a given destination by sending a Destination Up Response
with a status code of 'Not Interested', see Table 3. Receivers of
such responses MUST NOT send further messages concerning that
destination to the peer.
After exchanging a pair of Destination Down (Section 8.11) and This document requests Private Use numbering space in the DLEP
Destination Down Response (Section 8.12) messages, no messages signal/message, data item and status code registries for experimental
concerning the logical destination identified by the MAC Address data extensions. The intent is to allow for experimentation with new
item may be a sent without a previously sending a new Destination Up signals, messages, data items, and/or status codes, while still
message. An implementation receiving a message about a down retaining the documented DLEP behavior.
destination MUST terminate the session by issuing a Session
Termination message with a status code of 'Invalid Destination' and
transition to the Session Termination state.
7. DLEP Signal and Message Structure Use of the Private Use signals, messages, data items, status codes,
or behaviors MUST be announced as DLEP Extensions, during session
initialization, using extension identifiers from the Private Use
space in the Extensions Supported registry (Table 4), with a value
agreed upon (a priori) between the participating peers. DLEP
extensions using the Private Use numbering space are commonly
referred to as Experiments.
Multiple experiments MAY be announced in the Session Initialization
messages. However, use of multiple experiments in a single session
could lead to interoperability issues or unexpected results (e.g.,
clashes of experimental signals, messages, data items and/or status
code types), and is therefore discouraged. It is left to
implementations to determine the correct processing path (e.g., a
decision on whether to terminate the session, or to establish a
precedence of the conflicting definitions) if such conflicts arise.
7. Scalability
The protocol is intended to support thousands of destinations on a
given modem/router pair. At large scale, implementations SHOULD
consider employing techniques to prevent flooding a peer with a large
number of messages in a short time. It is recommended that
implementations consider a dampening algorithm to prevent a flapping
device from generating a large number of Destination Up/Destination
Down messages, for example. Implementations SHOULD also consider
techniques such as a hysteresis to lessen the impact of rapid, minor
fluctuations in link quality. The specific algorithms to be used for
handling flapping destinations and minor changes in link quality are
outside the scope of this specification.
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)
skipping to change at page 18, line 5 skipping to change at page 18, line 20
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.
7.1. 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 18, line 37 skipping to change at page 19, line 5
signal. This length SHALL NOT include the length of the header signal. This length SHALL NOT include the length of the header
itself. itself.
The DLEP signal header is immediately followed by one or more DLEP The DLEP signal header is immediately followed by one or more DLEP
data items, encoded in TLVs, as defined in this document. data items, encoded in TLVs, as defined in this document.
If an unrecognized, or unexpected signal is received, or a received If an unrecognized, or unexpected signal is received, or a received
signal contains unrecognized, invalid, or disallowed duplicate data signal contains unrecognized, invalid, or disallowed duplicate data
items, the receiving peer MUST ignore the signal. items, the receiving peer MUST ignore the signal.
7.2. 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
skipping to change at page 19, line 16 skipping to change at page 19, line 31
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 SHALL NOT include the length of the header
itself. itself.
The DLEP message header is immediately followed by one or more DLEP The DLEP message header is immediately followed by one or more DLEP
data items, encoded in TLVs, as defined in this document. data items, encoded in TLVs, as defined in this document.
If an unrecognized, or unexpected message is received, or a received If an unrecognized, or unexpected message is received, or a received
message contains unrecognized, invalid, or disallowed duplicate data message contains unrecognized, invalid, or disallowed duplicate data
items, the receiving peer MUST issue a Session Termination message items, the receiving peer MUST issue a Session Termination message
(Section 8.7) with a Status data item (Section 9.1) containing the (Section 9.7) with a Status data item (Section 10.1) containing the
most relevant status code, and transition to the Session Termination most relevant status code, and transition to the Session Termination
state. state.
7.3. 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... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 19, line 44 skipping to change at page 20, line 12
Data Item Type: An 16-bit unsigned integer field specifying the type Data Item Type: An 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 an 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 SHALL
NOT include the length of the header itself. NOT include the length of the header itself.
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.
8. 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 and messages are:
+-------------+-----------------------------------------------------+ +-------------+-----------------------------------------------------+
| Type Code | Description | | Type Code | Description |
+-------------+-----------------------------------------------------+ +-------------+-----------------------------------------------------+
| 0 | Reserved | | 0 | Reserved |
| 1 | Peer Discovery signal (Section 8.1) | | 1 | Peer Discovery signal (Section 9.1) |
| 2 | Peer Offer signal (Section 8.2) | | 2 | Peer Offer signal (Section 9.2) |
| 3 | Session Initialization message (Section 8.3) | | 3 | Session Initialization message (Section 9.3) |
| 4 | Session Initialization Response message (Section | | 4 | Session Initialization Response message (Section |
| | 8.4) | | | 9.4) |
| 5 | Session Update message (Section 8.5) | | 5 | Session Update message (Section 9.5) |
| 6 | Session Update Response message (Section 8.6) | | 6 | Session Update Response message (Section 9.6) |
| 7 | Session Termination message (Section 8.7) | | 7 | Session Termination message (Section 9.7) |
| 8 | Session Termination Response message (Section 8.8) | | 8 | Session Termination Response message (Section 9.8) |
| 9 | Destination Up message (Section 8.9) | | 9 | Destination Up message (Section 9.9) |
| 10 | Destination Up Response message (Section 8.10) | | 10 | Destination Up Response message (Section 9.10) |
| 11 | Destination Down message (Section 8.11) | | 11 | Destination Down message (Section 9.11) |
| 12 | Destination Down Response message (Section 8.12) | | 12 | Destination Down Response message (Section 9.12) |
| 13 | Destination Update message (Section 8.13) | | 13 | Destination Update message (Section 9.13) |
| 14 | Heartbeat message (Section 8.14) | | 14 | Heartbeat message (Section 9.14) |
| 15 | Link Characteristics Request message (Section 8.15) | | 15 | Link Characteristics Request message (Section 9.15) |
| 16 | Link Characteristics Response message (Section | | 16 | Link Characteristics Response message (Section |
| | 8.16) | | | 9.16) |
| 17-65519 | Reserved for future extensions | | 17-65519 | Reserved for future extensions |
| 65520-65534 | Private Use. Available for experiments | | 65520-65534 | Private Use. Available for experiments |
| 65535 | Reserved | | 65535 | Reserved |
+-------------+-----------------------------------------------------+ +-------------+-----------------------------------------------------+
Table 1: DLEP Signal/Message types Table 1: DLEP Signal/Message types
8.1. Peer Discovery Signal 9.1. Peer Discovery Signal
A Peer Discovery signal SHOULD be sent by a router to discover DLEP A Peer Discovery signal SHOULD be sent by a router to discover DLEP
modems in the network. The Peer Offer signal (Section 8.2) is modems in the network. The Peer Offer signal (Section 9.2) is
required to complete the discovery process. Implementations MAY required to complete the discovery process. Implementations MAY
implement their own retry heuristics in cases where it is determined implement their own retransmit heuristics in cases where it is
the Peer Discovery signal has timed out. determined the Peer Discovery signal has timed out.
To construct a Peer Discovery signal, the Signal Type value in the To construct a Peer Discovery signal, the Signal Type value in the
signal header is set to 1, from Table 1. signal header is set to 1, from Table 1.
The Peer Discovery signal MAY contain the following data item: The Peer Discovery signal MAY contain the following data item:
o Peer Type (Section 9.4) o Peer Type (Section 10.4)
8.2. Peer Offer Signal 9.2. Peer Offer Signal
A Peer Offer signal MUST be sent by a DLEP modem in response to a A Peer Offer signal MUST be sent by a DLEP modem in response to a
valid Peer Discovery signal (Section 8.1). valid Peer Discovery signal (Section 9.1).
The Peer Offer signal MUST be sent to the unicast address of the The Peer Offer signal MUST be sent to the unicast address of the
originator of the Peer Discovery signal. originator of the Peer Discovery signal.
To construct a Peer Offer signal, the Signal Type value in the signal To construct a Peer Offer signal, the Signal Type value in the signal
header is set to 2, from Table 1. header is set to 2, from Table 1.
The Peer Offer signal MAY contain the following data item: The Peer Offer signal MAY contain the following data item:
o Peer Type (Section 9.4) o Peer Type (Section 10.4)
The Peer Offer signal MAY contain one or more of any of the following The Peer Offer signal MAY contain one or more of any of the following
data items, with different values: data items, with different values:
o IPv4 Connection Point (Section 9.2) o IPv4 Connection Point (Section 10.2)
o IPv6 Connection Point (Section 9.3) o IPv6 Connection Point (Section 10.3)
The IP Connection Point data items indicate the unicast address the The IP Connection Point data items indicate the unicast address the
receiver of Peer Offer MUST use when connecting the DLEP TCP session. receiver of Peer Offer MUST use when connecting the DLEP TCP session.
If multiple IP Connection Point data items are present in the Peer If multiple IP Connection Point data items are present in the Peer
Offer signal, implementations MAY use their own heuristics to select Offer signal, implementations MAY use their own heuristics to select
the address to connect to. If no IP Connection Point data items are the address to connect to. If no IP Connection Point data items are
included in the Peer Offer signal, the receiver MUST use the origin included in the Peer Offer signal, the receiver MUST use the origin
address of the signal as the IP address, and the DLEP well-known port address of the signal as the IP address, and the DLEP well-known port
number (Section 12.7) to establish the TCP connection. number (Section 12.7) to establish the TCP connection.
8.3. Session Initialization Message 9.3. Session Initialization Message
A Session Initialization message MUST be sent by a router as the A Session Initialization message MUST be sent by a router as the
first message of the DLEP TCP session. It is sent by the router 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 after a TCP connect to an address/port combination that was obtained
either via receipt of a Peer Offer, or from a priori configuration. either via receipt of a Peer Offer, or from a priori configuration.
If any optional extensions are supported by the implementation, they If any optional extensions are supported by the implementation, they
MUST be enumerated in the Extensions Supported data item. If an MUST be enumerated in the Extensions Supported data item. If an
Extensions Supported data item does not exist in a Session Extensions Supported data item does not exist in a Session
Initialization message, the receiver of the message MUST conclude Initialization message, the receiver of the message MUST conclude
that there is no support for extensions in the sender. that there is no support for extensions in the sender.
Implementations supporting the Heartbeat Interval (Section 9.5) Implementations supporting the Heartbeat Interval (Section 10.5)
should understand that heartbeats are not fully established until should understand that heartbeats are not fully established until
receipt of Session Initialization Response message (Section 8.4), and receipt of Session Initialization Response message (Section 9.4), and
should therefore implement their own timeout and retry heuristics for should therefore implement their own timeout and retry heuristics for
this message. this message.
To construct a Session Initialization message, the Message Type value To construct a Session Initialization message, the Message Type value
in the message header is set to 3, from Table 1. in the message header is set to 3, from Table 1.
The Session Initialization message MUST contain one of each of the The Session Initialization message MUST contain one of each of the
following data items: following data items:
o Heartbeat Interval (Section 9.5) o Heartbeat Interval (Section 10.5)
The Session Initialization message MAY contain one of each of the The Session Initialization message MAY contain one of each of the
following data items: following data items:
o Peer Type (Section 9.4) o Peer Type (Section 10.4)
o Extensions Supported (Section 9.6) o Extensions Supported (Section 10.6)
A Session Initialization message MUST be acknowledged by the receiver A Session Initialization message MUST be acknowledged by the receiver
issuing a Session Initialization Response message (Section 8.4). issuing a Session Initialization Response message (Section 9.4).
8.4. Session Initialization Response Message As an exception to the general rule that an implementation receiving
an unrecognized data item in a message terminating the session with
an error, see Section 8.2, 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.
9.4. Session Initialization Response Message
A Session Initialization Response message MUST be sent in response to A Session Initialization Response message MUST be sent in response to
a received Session Initialization message (Section 8.3). The Session a received Session Initialization message (Section 9.3). The Session
Initialization Response message completes the DLEP session Initialization Response message completes the DLEP session
establishment; the sender of the message should transition to the In- establishment; the sender of the message should transition to the In-
Session state when the message is sent, and the receiver should Session state when the message is sent, and the receiver should
transition to the In-Session state upon receipt (and successful transition to the In-Session state upon receipt (and successful
parsing) of an acceptable Session Initialization Response message. parsing) of an acceptable Session Initialization Response message.
All supported metric data items MUST be included in the Session All supported metric data items MUST be included in the Session
Initialization Response message, with default values to be used on a Initialization Response message, with default values to be used on a
'modem-wide' basis. This can be viewed as the modem 'declaring' all 'modem-wide' basis. This can be viewed as the modem 'declaring' all
supported metrics at DLEP session initialization. Receipt of any supported metrics at DLEP session initialization. Receipt of any
skipping to change at page 23, line 15 skipping to change at page 24, line 21
After the Session Initialization/Session Initialization Response After the Session Initialization/Session Initialization Response
messages have been successfully exchanged, implementations MUST only messages have been successfully exchanged, implementations MUST only
use extensions that are supported by BOTH peers. use extensions that are supported by BOTH peers.
To construct a Session Initialization Response message, the Message To construct a Session Initialization Response message, the Message
Type value in the message header is set to 4, from Table 1. Type value in the message header is set to 4, from Table 1.
The Session Initialization Response message MUST contain one of each The Session Initialization Response message MUST contain one of each
of the following data items: of the following data items:
o Heartbeat Interval (Section 9.5) o Heartbeat Interval (Section 10.5)
o Maximum Data Rate (Receive) (Section 9.12) o Maximum Data Rate (Receive) (Section 10.12)
o Maximum Data Rate (Transmit) (Section 9.13) o Maximum Data Rate (Transmit) (Section 10.13)
o Current Data Rate (Receive) (Section 9.14) o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Transmit) (Section 9.15) o Current Data Rate (Transmit) (Section 10.15)
o Latency (Section 9.16) o Latency (Section 10.16)
The Session Initialization Response message MUST contain one of each The Session Initialization Response message MUST contain one of each
of the following data items, if the data item will be used during the of the following data items, if the data item will be used during the
lifetime of the session: lifetime of the session:
o Resources (Receive) (Section 9.17) o Resources (Receive) (Section 10.17)
o Resources (Transmit) (Section 9.18) o Resources (Transmit) (Section 10.18)
o Relative Link Quality (Receive) (Section 9.19) o Relative Link Quality (Receive) (Section 10.19)
o Relative Link Quality (Transmit) (Section 9.20) o Relative Link Quality (Transmit) (Section 10.20)
The Session Initialization Response message MAY contain one of each The Session Initialization Response message MAY contain one of each
of the following data items: of the following data items:
o Status (Section 9.1) o Status (Section 10.1)
o Peer Type (Section 9.4)
o Extensions Supported (Section 9.6) o Peer Type (Section 10.4)
o Extensions Supported (Section 10.6)
A receiver of a Session Initialization Response message without a A receiver of a Session Initialization Response message without a
Status data item MUST behave as if a Status data item with code Status data item MUST behave as if a Status data item with code
'Success' had been received. 'Success' had been received.
8.5. Session Update Message 9.5. Session Update Message
A Session Update message MAY be sent by a DLEP peer to indicate local A Session Update message MAY be sent by a DLEP peer to indicate local
Layer 3 address changes, or metric changes on a modem-wide basis. Layer 3 address changes, or metric changes on a modem-wide basis.
For example, addition of an IPv4 address to the router MAY prompt a For example, addition of an IPv4 address to the router MAY prompt a
Session Update message to its attached DLEP modems. Also, for Session Update message to its attached DLEP modems. Also, for
example, a modem that changes its Maximum Data Rate (Receive) for all example, a modem that changes its Maximum Data Rate (Receive) for all
destinations MAY reflect that change via a Session Update message to destinations MAY reflect that change via a Session Update message to
its attached router(s). its attached router(s).
Concerning Layer 3 addresses, if the modem is capable of Concerning Layer 3 addresses: If the modem is capable of
understanding and forwarding this information (via proprietary understanding and forwarding this information (via proprietary
mechanisms), the address update would prompt any remote DLEP modems mechanisms), the address update would prompt any remote DLEP modems
(DLEP-enabled modems in a remote node) to issue a Destination Update (DLEP-enabled modems in a remote node) to issue a Destination Update
message (Section 8.13) to their local routers with the new (or message (Section 9.13) to their local routers with the new (or
deleted) addresses. Modems that do not track Layer 3 addresses deleted) addresses. Modems that do not track Layer 3 addresses
SHOULD silently parse and ignore Layer 3 data items. The Session SHOULD silently parse and ignore Layer 3 data items. The Session
Update message MUST be acknowledged with a Session Update Response Update message MUST be acknowledged with a Session Update Response
message (Section 8.6). message (Section 9.6).
If metrics are supplied with the Session Update message (e.g., If metrics are supplied with the Session Update message (e.g.,
Maximum Data Rate), these metrics are considered to be modem-wide, Maximum Data Rate), these metrics are considered to be modem-wide,
and therefore MUST be applied to all destinations in the information and therefore MUST be applied to all destinations in the information
base associated with the router/modem session. base associated with the router/modem session.
Supporting implementations are free to employ heuristics to
retransmit Session Update messages. The sending of Session Update
messages for Layer 3 address changes SHOULD cease when either
participant (router or modem) determines that the other
implementation does not support Layer 3 address tracking.
To construct a Session Update message, the Message Type value in the To construct a Session Update message, the Message Type value in the
message header is set to 5, from Table 1. message header is set to 5, from Table 1.
The Session Update message MAY contain one of each of the following The Session Update message MAY contain one of each of the following
data items: data items:
o Maximum Data Rate (Receive) (Section 9.12) o Maximum Data Rate (Receive) (Section 10.12)
o Maximum Data Rate (Transmit) (Section 9.13) o Maximum Data Rate (Transmit) (Section 10.13)
o Current Data Rate (Receive) (Section 9.14) o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Transmit) (Section 9.15) o Current Data Rate (Transmit) (Section 10.15)
o Latency (Section 9.16) o Latency (Section 10.16)
o Resources (Receive) (Section 9.17) o Resources (Receive) (Section 10.17)
o Resources (Transmit) (Section 9.18)
o Relative Link Quality (Receive) (Section 9.19) o Resources (Transmit) (Section 10.18)
o Relative Link Quality (Receive) (Section 10.19)
o Relative Link Quality (Transmit) (Section 9.20) o Relative Link Quality (Transmit) (Section 10.20)
The Session Update message MAY contain one or more of the following The Session Update message MAY contain one or more of the following
data items, with different values: data items, with different values:
o IPv4 Address (Section 9.8) o IPv4 Address (Section 10.8)
o IPv6 Address (Section 9.9) o IPv6 Address (Section 10.9)
A Session Update message MUST be acknowledged by the receiver issuing A Session Update message MUST be acknowledged by the receiver issuing
a Session Update Response message (Section 8.6). a Session Update Response message (Section 9.6).
8.6. Session Update Response Message 9.6. Session Update Response Message
A Session Update Response message MUST be sent by implementations to A Session Update Response message MUST be sent by implementations to
indicate whether a Session Update message (Section 8.5) was indicate whether a Session Update message (Section 9.5) was
successfully received. successfully received.
To construct a Session Update Response message, the Message Type To construct a Session Update Response message, the Message Type
value in the message header is set to 6, from Table 1. value in the message header is set to 6, from Table 1.
The Session Update Response message MAY contain one of each of the The Session Update Response message MAY contain one of each of the
following data items: following data items:
o Status (Section 9.1) o Status (Section 10.1)
A receiver of a Session Update Response message without a Status data A receiver of a Session Update Response message without a Status data
item MUST behave as if a Status data item with code 'Success' had item MUST behave as if a Status data item with code 'Success' had
been received. been received.
8.7. Session Termination Message 9.7. Session Termination Message
A Session Termination message MUST be sent by a DLEP participant when A Session Termination message MUST be sent by a DLEP participant when
the router/modem session needs to be terminated. the router/modem session needs to be terminated.
To construct a Session Termination message, the Message Type value in To construct a Session Termination message, the Message Type value in
the message header is set to 7, from Table 1. the message header is set to 7, from Table 1.
The Session Termination message MAY contain one of each of the The Session Termination message MAY contain one of each of the
following data items: following data items:
o Status (Section 9.1) o Status (Section 10.1)
A receiver of a Session Termination message without a Status data A receiver of a Session Termination message without a Status data
item MUST behave as if a Status of 'Unknown reason for Session item MUST behave as if a Status of 'Unknown reason for Session
Termination' has been received. Termination' has been received.
A Session Termination message MUST be acknowledged by the receiver A Session Termination message MUST be acknowledged by the receiver
issuing a Session Termination Response message (Section 8.8). issuing a Session Termination Response message (Section 9.8).
8.8. Session Termination Response Message 9.8. Session Termination Response Message
A Session Termination Response message MUST be sent by a DLEP peer in A Session Termination Response message MUST be sent by a DLEP peer in
response to a received Session Termination message (Section 8.7). response to a received Session Termination message (Section 9.7).
Receipt of a Session Termination Response message completes the Receipt of a Session Termination Response message completes the
teardown of the router/modem session. teardown of the router/modem session.
To construct a Session Termination Response message, the Message Type To construct a Session Termination Response message, the Message Type
value in the message header is set to 8, from Table 1. value in the message header is set to 8, from Table 1.
The Session Termination Response message MAY contain one of each of The Session Termination Response message MAY contain one of each of
the following data items: the following data items:
o Status (Section 9.1) o Status (Section 10.1)
A receiver of a Session Termination Response message without a Status A receiver of a Session Termination Response message without a Status
data item MUST behave as if a Status data item with status code data item MUST behave as if a Status data item with status code
'Success', implying graceful termination, had been received. 'Success', implying graceful termination, had been received.
8.9. Destination Up Message 9.9. Destination Up Message
A Destination Up message can be sent either by the modem, to indicate A Destination Up message can be sent either by the modem, to indicate
that a new remote node has been detected, or by the router, to that a new remote node has been detected, or by the router, to
indicate the presence of a new logical destination (e.g., a Multicast indicate the presence of a new logical destination (e.g., a Multicast
group) in the network. group) in the network.
A Destination Up message MUST be acknowledged by the receiver issuing A Destination Up message MUST be acknowledged by the receiver issuing
a Destination Up Response message (Section 8.10). The sender of the a Destination Up Response message (Section 9.10). When a Destination
Destination Up message is free to define its retry heuristics in Up message is received and successfully processed, the receiver
event of a timeout. When a Destination Up message is received and should add knowledge of the new destination to its information base,
successfully processed, the receiver should add knowledge of the new indicating that the destination is accessible via the modem/router
destination to its information base, indicating that the destination pair.
is accessible via the modem/router pair.
To construct a Destination Up message, the Message Type value in the To construct a Destination Up message, the Message Type value in the
message header is set to 9, from Table 1. message header is set to 9, from Table 1.
The Destination Up message MUST contain one of each of the following The Destination Up message MUST contain one of each of the following
data items: data items:
o MAC Address (Section 9.7) o MAC Address (Section 10.7)
The Destination Up message MAY contain one of each of the following The Destination Up message MAY contain one of each of the following
data items: data items:
o Maximum Data Rate (Receive) (Section 9.12) o Maximum Data Rate (Receive) (Section 10.12)
o Maximum Data Rate (Transmit) (Section 9.13) o Maximum Data Rate (Transmit) (Section 10.13)
o Current Data Rate (Receive) (Section 9.14) o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Transmit) (Section 9.15) o Current Data Rate (Transmit) (Section 10.15)
o Latency (Section 9.16) o Latency (Section 10.16)
o Resources (Receive) (Section 9.17) o Resources (Receive) (Section 10.17)
o Resources (Transmit) (Section 9.18) o Resources (Transmit) (Section 10.18)
o Relative Link Quality (Receive) (Section 9.19) o Relative Link Quality (Receive) (Section 10.19)
o Relative Link Quality (Transmit) (Section 9.20) o Relative Link Quality (Transmit) (Section 10.20)
The Destination Up message MAY contain one or more of the following The Destination Up message MAY contain one or more of the following
data items, with different values: data items, with different values:
o IPv4 Address (Section 9.8) o IPv4 Address (Section 10.8)
o IPv6 Address (Section 9.9) o IPv6 Address (Section 10.9)
o IPv4 Attached Subnet (Section 9.10) o IPv4 Attached Subnet (Section 10.10)
o IPv6 Attached Subnet (Section 9.11) o IPv6 Attached Subnet (Section 10.11)
If the sender has IPv4 and/or IPv6 address information for a If the sender has IPv4 and/or IPv6 address information for a
destination it SHOULD include the relevant data items in the destination it SHOULD include the relevant data items in the
Destination Up message, reducing the need for the receiver to probe Destination Up message, reducing the need for the receiver to probe
for any address. for any address.
8.10. Destination Up Response Message 9.10. Destination Up Response Message
A DLEP participant MUST send a Destination Up Response message to A DLEP participant MUST send a Destination Up Response message to
indicate whether a Destination Up message (Section 8.9) was indicate whether a Destination Up message (Section 9.9) was
successfully processed. successfully processed.
To construct a Destination Up Response message, the Message Type To construct a Destination Up Response message, the Message Type
value in the message header is set to 10, from Table 1. value in the message header is set to 10, from Table 1.
The Destination Up Response message MUST contain one of each of the The Destination Up Response message MUST contain one of each of the
following data items: following data items:
o MAC Address (Section 9.7) o MAC Address (Section 10.7)
The Destination Up Response message MAY contain one of each of the The Destination Up Response message MAY contain one of each of the
following data items: following data items:
o Status (Section 9.1) o Status (Section 10.1)
A receiver of a Destination Up Response message without a Status data A receiver of a Destination Up Response message without a Status data
item MUST behave as if a Status data item with status code 'Success' item MUST behave as if a Status data item with status code 'Success'
had been received. had been received.
8.11. Destination Down Message 9.11. Destination Down Message
A DLEP peer MUST send a Destination Down message to report when a A DLEP peer MUST send a Destination Down message to report 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 8.12) MUST reachable. A Destination Down Response message (Section 9.12) MUST
be sent by the recipient of a Destination Down message to confirm be sent by the recipient of a Destination Down message to confirm
that the relevant data has been removed from the information base. that the relevant data has been removed from the information base.
The sender of the Destination Down message is free to define its
retry heuristics in event of a timeout.
To construct a Destination Down message, the Message Type value in To construct a Destination Down message, the Message Type value in
the message header is set to 11, from Table 1. the message header is set to 11, from Table 1.
The Destination Down message MUST contain one of each of the The Destination Down message MUST contain one of each of the
following data items: following data items:
o MAC Address (Section 9.7) o MAC Address (Section 10.7)
8.12. Destination Down Response Message 9.12. Destination Down Response Message
A DLEP participant MUST send a Destination Down Response message to A DLEP participant MUST send a Destination Down Response message to
indicate whether a received Destination Down message (Section 8.11) indicate whether a received Destination Down message (Section 9.11)
was successfully processed. If successfully processed, the sender of was successfully processed. If successfully processed, the sender of
the Response MUST have removed all entries in the information base the Response MUST have removed all entries in the information base
that pertain to the referenced destination. that pertain to the referenced destination.
To construct a Destination Down Response message, the Message Type To construct a Destination Down Response message, the Message Type
value in the message header is set to 12, from Table 1. value in the message header is set to 12, from Table 1.
The Destination Down Response message MUST contain one of each of the The Destination Down Response message MUST contain one of each of the
following data items: following data items:
o MAC Address (Section 9.7) o MAC Address (Section 10.7)
The Destination Down Response message MAY 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 9.1) o Status (Section 10.1)
A receiver of a Destination Down Response message without a Status A receiver of a Destination Down Response message without a Status
data item MUST behave as if a Status data item with status code data item MUST behave as if a Status data item with status code
'Success' had been received. 'Success' had been received.
8.13. Destination Update Message 9.13. Destination Update Message
A DLEP participant SHOULD send the Destination Update message when it A DLEP participant SHOULD send the Destination Update message when it
detects some change in the information base for a given destination detects some change in the information base for a given destination
(remote node or multicast group). Some examples of changes that (remote node or multicast group). Some examples of changes that
would prompt a Destination Update message are: would prompt 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 1.
The Destination Update message MUST contain one of each of the The Destination Update message MUST contain one of each of the
following data items: following data items:
o MAC Address (Section 9.7) o MAC Address (Section 10.7)
The Destination Update message MAY contain one of each of the The Destination Update message MAY contain one of each of the
following data items: following data items:
o Maximum Data Rate (Receive) (Section 9.12) o Maximum Data Rate (Receive) (Section 10.12)
o Maximum Data Rate (Transmit) (Section 9.13) o Maximum Data Rate (Transmit) (Section 10.13)
o Current Data Rate (Receive) (Section 9.14) o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Transmit) (Section 9.15) o Current Data Rate (Transmit) (Section 10.15)
o Latency (Section 9.16) o Latency (Section 10.16)
o Resources (Receive) (Section 9.17) o Resources (Receive) (Section 10.17)
o Resources (Transmit) (Section 9.18) o Resources (Transmit) (Section 10.18)
o Relative Link Quality (Receive) (Section 9.19) o Relative Link Quality (Receive) (Section 10.19)
o Relative Link Quality (Transmit) (Section 10.20)
o Relative Link Quality (Transmit) (Section 9.20)
The Destination Update message MAY contain one or more of the The Destination Update message MAY contain one or more of the
following data items, with different values: following data items, with different values:
o IPv4 Address (Section 9.8) o IPv4 Address (Section 10.8)
o IPv6 Address (Section 10.9)
o IPv6 Address (Section 9.9) 9.14. Heartbeat Message
8.14. Heartbeat Message While Heartbeat messages are not required by DLEP implementations, it
is strongly RECOMMENDED that Heartbeat messages be used.
A Heartbeat message SHOULD be sent by a DLEP participant every N A Heartbeat message SHOULD be sent by a DLEP participant every N
seconds, where N is defined in the Heartbeat Interval data item of seconds, where N is defined in the Heartbeat Interval data item of
the Session Initialization message (Section 8.3) or Session the Session Initialization message (Section 9.3) or Session
Initialization Response message (Section 8.4). Initialization Response message (Section 9.4).
Note that implementations setting the Heartbeat Interval to 0 Note that implementations setting the Heartbeat Interval to 0
effectively sets the interval to an infinite value, therefore this effectively sets the interval to an infinite value, turning off
message SHOULD NOT be sent. Heartbeat messages. Great care MUST be taken when exercising this
option.
The message is used by participants to detect when a DLEP session The message is used by participants to detect when a DLEP session
partner (either the modem or the router) is no longer communicating. partner (either the modem or the router) is no longer communicating.
Participants SHOULD allow two (2) heartbeat intervals to expire with Participants SHOULD allow two (2) heartbeat intervals to expire with
no traffic on the router/modem session before initiating DLEP session no traffic on the router/modem session before initiating DLEP session
termination procedures. termination procedures.
To construct a Heartbeat message, the Message Type value in the To construct a Heartbeat message, the Message Type value in the
message header is set to 14, from Table 1. message header is set to 14, from Table 1.
There are no valid data items for the Heartbeat message. There are no valid data items for the Heartbeat message.
8.15. Link Characteristics Request Message 9.15. Link Characteristics Request Message
The Link Characteristics Request message MAY be sent by the router to The Link Characteristics Request message MAY be sent by the router to
request that the modem initiate changes for specific characteristics request that the modem initiate changes for specific characteristics
of the link. The request can reference either a real destination of the link. The request can reference either a real destination
(e.g., a remote node), or a logical destination (e.g., a multicast (e.g., a remote node), or a logical destination (e.g., a multicast
group) within the network. 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. A
Link Characteristics Response message (Section 8.16) is required to Link Characteristics Response message (Section 9.16) is required to
complete the request. Issuing a Link Characteristics Request with complete the request. Issuing a Link Characteristics Request with
ONLY the MAC Address data item is a mechanism a peer MAY use to ONLY the MAC Address data item is a mechanism a peer MAY use to
request metrics (via the Link Characteristics Response) from its request metrics (via the Link Characteristics Response) from its
partner. partner.
The sender of a Link Characteristics Request message MAY attach a The sender of a Link Characteristics Request message should be aware
timer to the request using the Link Characteristics Response Timer that a request may take an extended period of time to complete.
data item. If a Link Characteristics Response message is received
after the timer expires, the sender MUST NOT assume that the request
succeeded. Implementations are free to define their retry heuristics
in event of a timeout.
To construct a Link Characteristics Request message, the Message Type To construct a Link Characteristics Request message, the Message Type
value in the message header is set to 15, from Table 1. value in the message header is set to 15, from Table 1.
The Link Characteristics Request message MUST contain one of each of The Link Characteristics Request message MUST contain one of each of
the following data items: the following data items:
o MAC Address (Section 9.7) o MAC Address (Section 10.7)
The Link Characteristics Request message MAY contain one of each of The Link Characteristics Request message MAY contain one of each of
the following data items: the following data items:
o Link Characteristics Response Timer (Section 9.21) o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Receive) (Section 9.14)
o Current Data Rate (Transmit) (Section 9.15) o Current Data Rate (Transmit) (Section 10.15)
o Latency (Section 9.16) o Latency (Section 10.16)
8.16. Link Characteristics Response Message 9.16. Link Characteristics Response Message
A DLEP participant MUST send a Link Characteristics Response message A DLEP participant MUST send a Link Characteristics Response message
to indicate whether a received Link Characteristics Request message to indicate whether a received Link Characteristics Request message
(Section 8.15) was successfully processed. The Link Characteristics (Section 9.15) was successfully processed. The Link Characteristics
Response message SHOULD contain a complete set of metric data items, Response message SHOULD contain a complete set of metric data items,
and MUST contain a full set (i.e. those declared in the Session and MUST contain a full set (i.e. those declared in the Session
Initialization Response message (Section 8.4)), if metrics were Initialization Response message (Section 9.4)), if metrics were
requested by only including a MAC address data item. It MUST contain 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 the same metric types as the request. The values in the metric data
items in the Link Characteristics Response message MUST reflect the items in the Link Characteristics Response message MUST reflect the
link characteristics after the request has been processed. link characteristics after the request has been processed.
If an implementation is not able to alter the characteristics of the If an implementation is not able to alter the characteristics of the
link in the manner requested, then a Status data item with status link in the manner requested, then a Status data item with status
code 'Request Denied', see Table 3, MUST be added to the message. code 'Request Denied', see Table 3, MUST be added to the message.
To construct a Link Characteristics Response message, the Message To construct a Link Characteristics Response message, the Message
Type value in the message header is set to 16, from Table 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 MUST contain one of each of
the following data items: the following data items:
o MAC Address (Section 9.7) o MAC Address (Section 10.7)
The Link Characteristics Response message SHOULD contain one of each The Link Characteristics Response message SHOULD contain one of each
of the following data items: of the following data items:
o Maximum Data Rate (Receive) (Section 9.12) o Maximum Data Rate (Receive) (Section 10.12)
o Maximum Data Rate (Transmit) (Section 9.13)
o Current Data Rate (Receive) (Section 9.14) o Maximum Data Rate (Transmit) (Section 10.13)
o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Transmit) (Section 9.15) o Current Data Rate (Transmit) (Section 10.15)
o Latency (Section 9.16) o Latency (Section 10.16)
The Link Characteristics Response message MAY contain one of each of The Link Characteristics Response message MAY contain one of each of
the following data items: the following data items:
o Resources (Receive) (Section 9.17) o Resources (Receive) (Section 10.17)
o Resources (Transmit) (Section 9.18) o Resources (Transmit) (Section 10.18)
o Relative Link Quality (Receive) (Section 9.19) o Relative Link Quality (Receive) (Section 10.19)
o Relative Link Quality (Transmit) (Section 9.20) o Relative Link Quality (Transmit) (Section 10.20)
o Status (Section 9.1) o Status (Section 10.1)
A receiver of a Link Characteristics Response message without a A receiver of a Link Characteristics Response message without a
Status data item MUST behave as if a Status data item with status Status data item MUST behave as if a Status data item with status
code 'Success' had been received. code 'Success' had been received.
9. DLEP Data Items 10. DLEP Data Items
Following is the list of core data items that MUST be recognized by a Following is the list of core data items that MUST be recognized by a
DLEP compliant implementation. As mentioned before, not all data DLEP compliant implementation. As mentioned before, not all data
items need be used during a session, but an implementation MUST items need be used during a session, but an implementation MUST
correctly process these data items when correctly associated with a correctly process these data items when correctly associated with a
signal or message. signal or message.
The core DLEP data items are: The core DLEP data items are:
+-------------+-----------------------------------------------------+ +-------------+-----------------------------------------------------+
| Type Code | Description | | Type Code | Description |
+-------------+-----------------------------------------------------+ +-------------+-----------------------------------------------------+
| 0 | Reserved | | 0 | Reserved |
| 1 | Status (Section 9.1) | | 1 | Status (Section 10.1) |
| 2 | IPv4 Connection Point (Section 9.2) | | 2 | IPv4 Connection Point (Section 10.2) |
| 3 | IPv6 Connection Point (Section 9.3) | | 3 | IPv6 Connection Point (Section 10.3) |
| 4 | Peer Type (Section 9.4) | | 4 | Peer Type (Section 10.4) |
| 5 | Heartbeat Interval (Section 9.5) | | 5 | Heartbeat Interval (Section 10.5) |
| 6 | Extensions Supported (Section 9.6) | | 6 | Extensions Supported (Section 10.6) |
| 7 | MAC Address (Section 9.7) | | 7 | MAC Address (Section 10.7) |
| 8 | IPv4 Address (Section 9.8) | | 8 | IPv4 Address (Section 10.8) |
| 9 | IPv6 Address (Section 9.9) | | 9 | IPv6 Address (Section 10.9) |
| 10 | IPv4 Attached Subnet (Section 9.10) | | 10 | IPv4 Attached Subnet (Section 10.10) |
| 11 | IPv6 Attached Subnet (Section 9.11) | | 11 | IPv6 Attached Subnet (Section 10.11) |
| 12 | Maximum Data Rate (Receive) MDRR) (Section 9.12) | | 12 | Maximum Data Rate (Receive) MDRR) (Section 10.12) |
| 13 | Maximum Data Rate (Transmit) (MDRT) (Section 9.13) | | 13 | Maximum Data Rate (Transmit) (MDRT) (Section 10.13) |
| 14 | Current Data Rate (Receive) (CDRR) (Section 9.14) | | 14 | Current Data Rate (Receive) (CDRR) (Section 10.14) |
| 15 | Current Data Rate (Transmit) (CDRT) (Section 9.15) | | 15 | Current Data Rate (Transmit) (CDRT) (Section 10.15) |
| 16 | Latency (Section 9.16) | | 16 | Latency (Section 10.16) |
| 17 | Resources (Receive) (RESR) (Section 9.17) | | 17 | Resources (Receive) (RESR) (Section 10.17) |
| 18 | Resources (Transmit) (REST) (Section 9.18) | | 18 | Resources (Transmit) (REST) (Section 10.18) |
| 19 | Relative Link Quality (Receive) (RLQR) (Section | | 19 | Relative Link Quality (Receive) (RLQR) (Section |
| | 9.19) | | | 10.19) |
| 20 | Relative Link Quality (Transmit) (RLQT) (Section | | 20 | Relative Link Quality (Transmit) (RLQT) (Section |
| | 9.20) | | | 10.20) |
| 21 | Link Characteristics Response Timer (Section 9.21) | | 21-65407 | Reserved for future extensions |
| 22-24 | Credit Windowing (Section 10) extension data items |
| 25-65407 | Reserved for future extensions |
| 65408-65534 | Private Use. Available for experiments | | 65408-65534 | Private Use. Available for experiments |
| 65535 | Reserved | | 65535 | Reserved |
+-------------+-----------------------------------------------------+ +-------------+-----------------------------------------------------+
Table 2: DLEP Data Item types Table 2: DLEP Data Item types
9.1. Status 10.1. Status
The Status data item MAY appear in the Session Initialization The Status data item MAY appear in the Session Initialization
Response (Section 8.4), Session Termination (Section 8.7), Session Response (Section 9.4), Session Termination (Section 9.7), Session
Termination Response (Section 8.8), Session Update Response Termination Response (Section 9.8), Session Update Response
(Section 8.6), Destination Up Response (Section 8.10), Destination (Section 9.6), Destination Up Response (Section 9.10), Destination
Down Response (Section 8.12) and Link Characteristics Response Down Response (Section 9.12) and Link Characteristics Response
(Section 8.16) messages. (Section 9.16) messages.
For the Session Termination message (Section 8.7), the Status data For the Session Termination message (Section 9.7), the Status data
item indicates a reason for the termination. For all acknowledgement item indicates a reason for the termination. For all acknowledgement
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.
skipping to change at page 34, line 48 skipping to change at page 36, line 18
+-------------+---------+-----------+-------------------------------+ +-------------+---------+-----------+-------------------------------+
| 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 expected |
| Message | | | while the device was in the | | Message | | | while the device was in the |
| | | | current state, e.g., a | | | | | current state, e.g., a |
| | | | Session Initialization | | | | | Session Initialization |
| | | | message (Section 8.3) in the | | | | | message (Section 9.3) in the |
| | | | In-Session state. | | | | | In-Session state. |
| Invalid | 3 | Terminate | One or more data items in the | | Invalid | 3 | Terminate | One or more data items in the |
| Data | | | message are invalid, | | Data | | | message are invalid, |
| | | | unexpected or incorrectly | | | | | unexpected or incorrectly |
| | | | duplicated. | | | | | duplicated. |
| Invalid | 4 | Terminate | The destination provided in | | Invalid | 4 | Terminate | The destination provided in |
| Destination | | | the message does not match a | | Destination | | | the message does not match a |
| | | | previously announced | | | | | previously announced |
| | | | destination. For example, in | | | | | destination. For example, in |
| | | | the Link Characteristic | | | | | the Link Characteristic |
| | | | Response message (Section | | | | | Response message (Section |
| | | | 8.16). | | | | | 9.16). |
| <Reserved> | 5-90 | Terminate | Reserved for future | | Timed Out | 5 | Terminate | The session has timed out. |
| <Reserved> | 6-90 | Terminate | Reserved for future |
| | | | extensions. | | | | | extensions. |
| <Private | 91-99 | Terminate | Available for experiments. | | <Private | 91-99 | Terminate | Available for experiments. |
| Use> | | | | | Use> | | | |
| 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. a Destination |
| | | | Up Response message (Section | | | | | Up Response message (Section |
| | | | 8.10) to indicate no further | | | | | 9.10) to indicate no further |
| | | | messages about the | | | | | messages about the |
| | | | destination. | | | | | destination. |
| Request | 101 | Continue | The receiver refuses to | | Request | 101 | Continue | The receiver refuses to |
| Denied | | | complete the request. | | Denied | | | complete the request. |
| Timed Out | 102 | Continue | The operation could not be | | <Reserved> | 102-243 | Continue | Reserved for future |
| | | | completed in the time |
| | | | allowed. |
| <Reserved> | 103-243 | Continue | Reserved for future |
| | | | extensions. | | | | | extensions. |
| <Private | 244-254 | Continue | Available for experiments. | | <Private | 244-254 | Continue | Available for experiments. |
| Use> | | | | | Use> | | | |
| <Reserved> | 255 | Terminate | Reserved. | | <Reserved> | 255 | Terminate | Reserved. |
+-------------+---------+-----------+-------------------------------+ +-------------+---------+-----------+-------------------------------+
Table 3: DLEP Status Codes Table 3: DLEP Status Codes
A failure mode of 'Terminate' indicates that the session MUST be A failure mode of 'Terminate' indicates that the session MUST be
terminated after sending a response containing the status code. A terminated after sending a response containing the status code. A
failure mode of 'Continue' indicates that the session SHOULD continue failure mode of 'Continue' indicates that the session SHOULD continue
as normal. as normal.
9.2. IPv4 Connection Point 10.2. IPv4 Connection Point
The IPv4 Connection Point data item MAY appear in the Peer Offer The IPv4 Connection Point data item MAY appear in the Peer Offer
signal (Section 8.2). signal (Section 9.2).
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 DLEP modem available for
connections. If provided, the receiver MUST use this information to connections. If provided, the receiver MUST use this information to
perform the TCP connect to the DLEP server. perform the TCP connect to the DLEP server.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Use TLS | 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)
Use TLS: Value indicating whether the TCP connection should use TLS Flags: Flags field, defined below.
(1), or not (0). Values other than 0 or 1 MUST be considered as
invalid.
IPv4 Address: The IPv4 address listening on the DLEP modem. IPv4 Address: The IPv4 address listening on the DLEP modem.
TCP Port Number: TCP Port number on the DLEP modem. TCP Port Number: TCP Port number on the DLEP 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 receiver MUST use the DLEP well-known port the Length field is 5, the receiver MUST use the DLEP well-known port
number (Section 12.7) to establish the TCP connection. number (Section 12.7) to establish the TCP connection.
9.3. IPv6 Connection Point The Flags field is defined as:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| MBZ |T|
+-+-+-+-+-+-+-+-+
T: Use TLS flag, indicating whether the TCP connection requires the
use of TLS (1), or not (0).
MBZ: MUST be zero. Reserved for future use.
10.3. IPv6 Connection Point
The IPv6 Connection Point data item MAY appear in the Peer Offer The IPv6 Connection Point data item MAY appear in the Peer Offer
signal (Section 8.2). signal (Section 9.2).
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 DLEP modem available for
connections. If provided, the receiver MUST use this information to connections. If provided, the receiver MUST use this information to
perform the TCP connect to the DLEP server. perform the TCP connect to the DLEP server.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Use TLS | IPv6 Address : | Flags | IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Address : : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Address : : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Address : : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: ...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)
Use TLS: Value indicating whether the TCP connection should use TLS Flags: Flags field, defined below.
(1), or not (0). Values other than 0 or 1 MUST be considered as
invalid.
IPv6 Address: The IPv6 address listening on the DLEP modem. IPv6 Address: The IPv6 address listening on the DLEP modem.
TCP Port Number: TCP Port number on the DLEP modem. TCP Port Number: TCP Port number on the DLEP 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 receiver MUST use the DLEP well-known the Length field is 17, the receiver MUST use the DLEP well-known
port number (Section 12.7) to establish the TCP connection. port number (Section 12.7) to establish the TCP connection.
9.4. Peer Type The Flags field is defined as:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| MBZ |T|
+-+-+-+-+-+-+-+-+
T: Use TLS flag, indicating whether the TCP connection requires the
use of TLS (1), or not (0).
MBZ: MUST be zero. Reserved for future use.
10.4. Peer Type
The Peer Type data item MAY appear in the Peer Discovery The Peer Type data item MAY appear in the Peer Discovery
(Section 8.1) and Peer Offer (Section 8.2) signals, and the Session (Section 9.1) and Peer Offer (Section 9.2) signals, and the Session
Initialization (Section 8.3) and Session Initialization Response Initialization (Section 9.3) and Session Initialization Response
(Section 8.4) messages. (Section 9.4) 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
skipping to change at page 38, line 21 skipping to change at page 39, line 47
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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. For example, a satellite modem
might set this variable to "Satellite terminal". Since this data might set this variable to "Satellite terminal". Since this data
item is intended to provide additional information for display item is intended to provide additional information for display
commands, sending implementations SHOULD limit the data to commands, sending implementations SHOULD limit the data to
printable characters, and receiving implmentations SHOULD check printable characters, and receiving implementations SHOULD check
the data for printable characters. 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.
9.5. Heartbeat Interval 10.5. Heartbeat Interval
The Heartbeat Interval data item MUST appear in both the Session The Heartbeat Interval data item MUST appear in both the Session
Initialization (Section 8.3) and Session Initialization Response Initialization (Section 9.3) and Session Initialization Response
(Section 8.4) messages to indicate the Heartbeat timeout window to be (Section 9.4) messages to indicate the Heartbeat timeout window to be
used by the sender. used by the sender.
The Interval is used to specify a period (in seconds) for Heartbeat The Interval is used to specify a period (in seconds) for Heartbeat
messages (Section 8.14). By specifying an Interval value of 0, messages (Section 9.14). By specifying an Interval value of 0,
implementations MAY indicate the desire to disable Heartbeat messages implementations MAY indicate the desire to disable Heartbeat messages
entirely (i.e., the Interval is set to an infinite value). However, entirely (i.e., the Interval is set to an infinite value). However,
it is RECOMMENDED that implementations use non-0 timer values. 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 |
skipping to change at page 39, line 4 skipping to change at page 40, line 31
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 | | Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 5 Data Item Type: 5
Length: 2 Length: 2
Interval: 0 = Do not use heartbeats on this DLEP session. Non-zero Interval: 0 = Do not use heartbeats on this DLEP session. Non-zero
= Interval, in seconds, for heartbeat messages. = Interval, in seconds, for heartbeat messages.
9.6. Extensions Supported 10.6. Extensions Supported
The Extensions Supported data item MAY be used in both the Session The Extensions Supported data item MAY be used in both the Session
Initialization (Section 8.3) and Session Initialization Response Initialization (Section 9.3) and Session Initialization Response
(Section 8.4) messages. (Section 9.4) 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:
skipping to change at page 39, line 38 skipping to change at page 41, line 21
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
9.7. MAC Address 10.7. MAC Address
The MAC address data item MUST appear in all destination-oriented The MAC address data item MUST appear in all destination-oriented
messages (i.e., Destination Up (Section 8.9), Destination Up Response messages (i.e., Destination Up (Section 9.9), Destination Up Response
(Section 8.10), Destination Down (Section 8.11), Destination Down (Section 9.10), Destination Down (Section 9.11), Destination Down
Response (Section 8.12), Destination Update (Section 8.13), Link Response (Section 9.12), Destination Update (Section 9.13), Link
Characteristics Request (Section 8.15), and Link Characteristics Characteristics Request (Section 9.15), and Link Characteristics
Response (Section 8.16)). Response (Section 9.16)).
The MAC Address data item contains the address of the destination on 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 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. 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 40, line 23 skipping to change at page 42, line 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: 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.
9.8. IPv4 Address 10.8. IPv4 Address
The IPv4 Address data item MAY appear in the Session Update The IPv4 Address data item MAY appear in the Session Update
(Section 8.5), Destination Up (Section 8.9) and Destination Update (Section 9.5), Destination Up (Section 9.9) and Destination Update
(Section 8.13) messages. (Section 9.13) 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Add/Drop | IPv4 Address : | Flags | IPv4 Address :
| Indicator | :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv4 | : ...cont. |
: Address |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Data Item Type: 8 Data Item Type: 8
Length: 5 Length: 5
Add/Drop: Value indicating whether this is a new or existing address
(1), or a withdrawal of an address (0). Values other than 0 or 1 Flags: Flags field, defined below.
MUST be considered as invalid.
IPv4 Address: The IPv4 address of the destination or peer. IPv4 Address: The IPv4 address of the destination or peer.
9.9. IPv6 Address The Flags field is defined as:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| MBZ |A|
+-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing
address (1), or a withdrawal of an address (0).
MBZ: MUST be zero. Reserved for future use.
10.9. IPv6 Address
The IPv6 Address data item MAY appear in the Session Update The IPv6 Address data item MAY appear in the Session Update
(Section 8.5), Destination Up (Section 8.9) and Destination Update (Section 9.5), Destination Up (Section 9.9) and Destination Update
(Section 8.13) messages. When included in Destination messages, this (Section 9.13) messages. When included in Destination messages, this
data item contains the IPv6 address of the destination. When data item contains the IPv6 address of the destination. When
included in the Session Update message, this data item contains the included in the Session Update message, this data item contains the
IPv6 address of the peer. In either case, the data item also IPv6 address of the peer. In either case, the data item also
contains an indication of whether this is a new or existing address, contains an indication of whether this is a new or existing address,
or is a deletion of a previously known 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Add/Drop | IPv6 Address : | Flags | IPv6 Address :
| Indicator | :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Address : : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Address : : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Address : : IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Address | : IPv6 Address |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Data Item Type: 9 Data Item Type: 9
Length: 17 Length: 17
Add/Drop: Value indicating whether this is a new or existing address Flags: Flags field, defined below.
(1), or a withdrawal of an address (0). Values other than 0 or 1
MUST be considered as invalid.
IPv6 Address: IPv6 Address of the destination or peer. IPv6 Address: IPv6 Address of the destination or peer.
9.10. IPv4 Attached Subnet The Flags field is defined as:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| MBZ |A|
+-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing
address (1), or a withdrawal of an address (0).
MBZ: MUST be zero. Reserved for future use.
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, or 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. The aware of an IPv4 subnet being present at a remote destination, or
IPv4 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 8.9) message. Once an IPv4 Subnet has been declared on a destination. The IPv4 Attached Subnet data item MAY appear in the
device, the declaration SHALL NOT be withdrawn without withdrawing Destination Up (Section 9.9) message.
the destination (via the Destination Down message (Section 8.11)) and
re-issuing the Destination Up message.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Attached Subnet | | Flags | IPv4 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Len. | : ...cont. |Prefix Length |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 10 Data Item Type: 10
Length: 5 Length: 6
Flags: Flags field, defined below.
IPv4 Subnet: The IPv4 subnet reachable at the destination. IPv4 Subnet: The IPv4 subnet reachable at the destination.
Prefix Length: Length of the prefix (1-32) for the IPv4 subnet. A Prefix Length: Length of the prefix (1-32) for the IPv4 subnet. A
prefix length outside the speficied range MUST be considered as prefix length outside the specified range MUST be considered as
invalid. invalid.
9.11. IPv6 Attached Subnet The Flags field is defined as:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| MBZ |A|
+-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing subnet
address (1), or a withdrawal of a subnet address (0).
MBZ: MUST be zero. Reserved for future use.
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, or 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. The
IPv6 Attached Subnet data item MAY appear in the Destination Up IPv6 Attached Subnet data item MAY appear in the Destination Up
(Section 8.9) message. As in the case of the IPv4 attached Subnet (Section 9.9) message. As in the case of the IPv4 attached Subnet
data item above, once an IPv6 attached subnet has been declared, it data item above, once an IPv6 attached subnet has been declared, it
SHALL NOT be withdrawn without withdrawing the destination (via the SHALL NOT be withdrawn without withdrawing the destination (via the
Destination Down message (Section 8.11)) and re-issuing the Destination Down message (Section 9.11)) and re-issuing the
Destination Up message. Destination Up message.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Attached Subnet : | Flags | IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Attached Subnet : : IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Attached Subnet : : IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Attached Subnet | : IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Len. | : ...cont. | Prefix Len. |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 11 Data Item Type: 11
Length: 17 Length: 18
IPv4 Subnet: The IPv6 subnet reachable at the destination. Flags: Flags field, defined below.
IPv6 Attached Subnet: The IPv6 subnet reachable at the destination.
Prefix Length: Length of the prefix (1-128) for the IPv6 subnet. A Prefix Length: Length of the prefix (1-128) for the IPv6 subnet. A
prefix length outside the specified range MUST be considered as prefix length outside the specified range MUST be considered as
invalid. invalid.
9.12. Maximum Data Rate (Receive) The Flags field is defined as:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| MBZ |A|
+-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing subnet
address (1), or a withdrawal of a subnet address (0).
MBZ: MUST be zero. Reserved for future use.
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 MUST appear in the
Session Initialization Response message (Section 8.4), and MAY appear Session Initialization Response message (Section 9.4), and MAY appear
in the Session Update (Section 8.5), Destination Up (Section 8.9), in the Session Update (Section 9.5), Destination Up (Section 9.9),
Destination Update (Section 8.13) and Link Characteristics Response Destination Update (Section 9.13) and Link Characteristics Response
(Section 8.16) messages to indicate the maximum theoretical data (Section 9.16) messages to indicate the maximum theoretical data
rate, in bits per second, that can be achieved while receiving data rate, in bits per second, that can be achieved while receiving data
on the link. 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 |
skipping to change at page 44, line 4 skipping to change at page 46, line 37
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) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
9.13. 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 MUST appear in the
Session Initialization Response message (Section 8.4), and MAY appear Session Initialization Response message (Section 9.4), and MAY appear
in the Session Update (Section 8.5), Destination Up (Section 8.9), in the Session Update (Section 9.5), Destination Up (Section 9.9),
Destination Update (Section 8.13) and Link Characteristics Response Destination Update (Section 9.13) and Link Characteristics Response
(Section 8.16) messages to indicate the maximum theoretical data (Section 9.16) messages to indicate the maximum theoretical data
rate, in bits per second, that can be achieved while transmitting rate, in bits per second, that can be achieved while transmitting
data on the link. 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 |
skipping to change at page 44, line 43 skipping to change at page 47, line 28
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
9.14. 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 MUST appear in the
Session Initialization Response message (Section 8.4), and MAY appear Session Initialization Response message (Section 9.4), and MAY appear
in the Session Update (Section 8.5), Destination Up (Section 8.9), in the Session Update (Section 9.5), Destination Up (Section 9.9),
Destination Update (Section 8.13) and Link Characteristics Response Destination Update (Section 9.13) and Link Characteristics Response
(Section 8.16) messages to indicate the rate at which the link is (Section 9.16) messages to indicate the rate at which the link is
currently operating for receiving traffic. currently operating for receiving traffic.
When used in the Link Characteristics Request message (Section 8.15), When used in the Link Characteristics Request message (Section 9.15),
CDRR represents the desired receive rate, in bits per second, on the CDRR represents the desired receive rate, in bits per second, on the
link. 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 |
skipping to change at page 45, line 34 skipping to change at page 48, line 27
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.
9.15. 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 MUST appear in the
Session Initialization Response message (Section 8.4), and MAY appear Session Initialization Response message (Section 9.4), and MAY appear
in the Session Update (Section 8.5), Destination Up (Section 8.9), in the Session Update (Section 9.5), Destination Up (Section 9.9),
Destination Update (Section 8.13), and Link Characteristics Response Destination Update (Section 9.13), and Link Characteristics Response
(Section 8.16) messages to indicate the rate at which the link is (Section 9.16) messages to indicate the rate at which the link is
currently operating for transmitting traffic. currently operating for transmitting traffic.
When used in the Link Characteristics Request message (Section 8.15), When used in the Link Characteristics Request message (Section 9.15),
CDRT represents the desired transmit rate, in bits per second, on the CDRT represents the desired transmit rate, in bits per second, on the
link. 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 |
skipping to change at page 46, line 27 skipping to change at page 49, line 16
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.
9.16. Latency 10.16. Latency
The Latency data item MUST appear in the Session Initialization The Latency data item MUST appear in the Session Initialization
Response message (Section 8.4), and MAY appear in the Session Update Response message (Section 9.4), and MAY appear in the Session Update
(Section 8.5), Destination Up (Section 8.9), Destination Update (Section 9.5), Destination Up (Section 9.9), Destination Update
(Section 8.13), and Link Characteristics Response (Section 8.16) (Section 9.13), and Link Characteristics Response (Section 9.16)
messages to indicate the amount of latency, in microseconds, on the messages to indicate the amount of latency, in microseconds, on the
link. link.
When used in the Link Characteristics Request message (Section 8.15), When used in the Link Characteristics Request message (Section 9.15),
Latency represents the maximum latency desired on the link. Latency represents the maximum latency desired on the link.
The Latency value is reported as delay. The calculation of latency The Latency value is reported as delay. The calculation of latency
is implementation dependent. For example, the latency may be a is implementation dependent. For example, the latency may be a
running average calculated from the internal queuing. 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 |
skipping to change at page 47, line 4 skipping to change at page 49, line 41
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.
9.17. Resources (Receive) 10.17. Resources (Receive)
The Resources (Receive) (RESR) data item MAY appear in the Session The Resources (Receive) (RESR) data item MAY appear in the Session
Initialization Response message (Section 8.4), Session Update Initialization Response message (Section 9.4), Session Update
(Section 8.5), Destination Up (Section 8.9), Destination Update (Section 9.5), Destination Up (Section 9.9), Destination Update
(Section 8.13) and Link Characteristics Response (Section 8.16) (Section 9.13) and Link Characteristics Response (Section 9.16)
messages to indicate the amount of resources for reception (with 0 messages to indicate the amount of resources for reception (with 0
meaning 'no resources available', and 100 meaning 'all resources meaning 'no resources available', and 100 meaning 'all resources
available') at the destination. The list of resources that might be available') at the destination. The list of resources that might be
considered is beyond the scope of this document, and is left to considered is beyond the scope of this document, and is left to
implementations to decide. implementations to decide.
The Resources (Receive) data item contains the following fields: The Resources (Receive) 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
skipping to change at page 47, line 45 skipping to change at page 50, line 38
Length: 1 Length: 1
Resources (Receive): An 8-bit integer percentage, 0-100, Resources (Receive): An 8-bit integer percentage, 0-100,
representing the amount of resources allocated to receiving data. representing the amount of resources allocated to receiving data.
Any value greater than 100 MUST be considered as invalid. Any value greater than 100 MUST be considered as invalid.
If a device cannot calculate RESR, this data item SHOULD NOT be If a device cannot calculate RESR, this data item SHOULD NOT be
issued. issued.
9.18. Resources (Transmit) 10.18. Resources (Transmit)
The Resources (Transmit) (REST) data item MAY appear in the Session The Resources (Transmit) (REST) data item MAY appear in the Session
Initialization Response message (Section 8.4), Session Update Initialization Response message (Section 9.4), Session Update
(Section 8.5), Destination Up (Section 8.9), Destination Update (Section 9.5), Destination Up (Section 9.9), Destination Update
(Section 8.13) and Link Characteristics Response (Section 8.16) (Section 9.13) and Link Characteristics Response (Section 9.16)
messages to indicate the amount of resources for transmission (with 0 messages to indicate the amount of resources for transmission (with 0
meaning 'no resources available', and 100 meaning 'all resources meaning 'no resources available', and 100 meaning 'all resources
available') at the destination. The list of resources that might be available') at the destination. The list of resources that might be
considered is beyond the scope of this document, and is left to considered is beyond the scope of this document, and is left to
implementations to decide. implementations to decide.
The Resources (Transmit) data item contains the following fields: The Resources (Transmit) 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
skipping to change at page 48, line 30 skipping to change at page 51, line 24
Length: 1 Length: 1
Resources (Transmit): An 8-bit integer percentage, 0-100, Resources (Transmit): An 8-bit integer percentage, 0-100,
representing the amount of resources allocated to transmitting representing the amount of resources allocated to transmitting
data. Any value greater than 100 MUST be considered as invalid. data. Any value greater than 100 MUST be considered as invalid.
If a device cannot calculate REST, this data item SHOULD NOT be If a device cannot calculate REST, this data item SHOULD NOT be
issued. issued.
9.19. Relative Link Quality (Receive) 10.19. Relative Link Quality (Receive)
The Relative Link Quality (Receive) (RLQR) data item MAY appear in The Relative Link Quality (Receive) (RLQR) data item MAY appear in
the Session Initialization Response message (Section 8.4), Session the Session Initialization Response message (Section 9.4), Session
Update (Section 8.5), Destination Up (Section 8.9), Destination Update (Section 9.5), Destination Up (Section 9.9), Destination
Update (Section 8.13) and Link Characteristics Response Update (Section 9.13) and Link Characteristics Response
(Section 8.16) messages to indicate the quality of the link for (Section 9.16) messages to indicate the quality of the link for
receiving data. receiving data.
The Relative Link Quality (Receive) data item contains the following 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 49, line 14 skipping to change at page 52, line 8
Length: 1 Length: 1
Relative Link Quality (Receive): A non-dimensional 8-bit integer, Relative Link Quality (Receive): A non-dimensional 8-bit integer,
0-100, representing relative link quality. A value of 100 0-100, representing relative link quality. A value of 100
represents a link of the highest quality. Any value greater than represents a link of the highest quality. Any value greater than
100 MUST be considered as invalid. 100 MUST be considered as invalid.
If a device cannot calculate the RLQR, this data item SHOULD NOT be If a device cannot calculate the RLQR, this data item SHOULD NOT be
issued. issued.
9.20. Relative Link Quality (Transmit) 10.20. Relative Link Quality (Transmit)
The Relative Link Quality (Transmit) (RLQT) data item MAY appear in The Relative Link Quality (Transmit) (RLQT) data item MAY appear in
the Session Initialization Response message (Section 8.4), Session the Session Initialization Response message (Section 9.4), Session
Update (Section 8.5), Destination Up (Section 8.9), Destination Update (Section 9.5), Destination Up (Section 9.9), Destination
Update (Section 8.13) and Link Characteristics Response Update (Section 9.13) and Link Characteristics Response
(Section 8.16) messages to indicate the quality of the link for (Section 9.16) messages to indicate the quality of the link for
transmitting data. 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 49, line 46 skipping to change at page 52, line 40
Length: 1 Length: 1
Relative Link Quality (Transmit): A non-dimensional 8-bit integer, Relative Link Quality (Transmit): A non-dimensional 8-bit integer,
0-100, representing relative link quality. A value of 100 0-100, representing relative link quality. A value of 100
represents a link of the highest quality. Any value greater than represents a link of the highest quality. Any value greater than
100 MUST be considered as invalid. 100 MUST be considered as invalid.
If a device cannot calculate the RLQT, this data item SHOULD NOT be If a device cannot calculate the RLQT, this data item SHOULD NOT be
issued. issued.
9.21. Link Characteristics Response Timer
The Link Characteristics Response Timer data item MAY appear in the
Link Characteristics Request message (Section 8.15) to indicate the
desired number of seconds the sender will wait for a response to the
request. If this data item is omitted, implementations supporting
the Link Characteristics Request SHOULD choose a default value.
The Link Characteristics Response Timer 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interval |
+-+-+-+-+-+-+-+-+
Data Item Type: 21
Length: 1
Interval: 0 = Do not use timeouts for this Link Characteristics
request. Non-zero = Interval, in seconds, to wait before
considering this Link Characteristics Request lost.
10. Credit-Windowing
DLEP includes an optional Protocol Extension for a credit-windowing
scheme analogous to the one documented in [RFC5578]. In this scheme,
data plane traffic flowing between the router and modem is controlled
by the availability of credits. Credits are expressed as if two
unidirectional windows exist between the modem and router. This
document identifies these windows as the 'Modem Receive Window'
(MRW), and the 'Router Receive Window' (RRW).
If the credit-windowing extension is used, credits MUST be granted by
the receiver on a given window - that is, on the 'Modem Receive
Window' (MRW), the modem is responsible for granting credits to the
router, allowing it (the router) to send data plane traffic to the
modem. Likewise, the router is responsible for granting credits on
the RRW, which allows the modem to send data plane traffic to the
router.
Credits are managed on a destination-specific basis; that is,
separate credit counts are maintained for each destination requiring
the service. Credits do not apply to the DLEP session that exists
between routers and modems; they are applied only to the data plane
traffic.
Credits represent the number of octets, or an increment in the number
of octets, that MAY be sent on the given window. When sending data
plane traffic to a credit-enabled peer, the sender MUST decrement the
appropriate window by the size of the data being sent. For example,
when sending data plane traffic via the modem, the router MUST
decriment the 'Modem Receive Window' (MRW) for the corresponding
destination. When the number of available credits to the destination
reaches 0, a sender MUST stop sending data plane traffic to the
destination, until additional credits are supplied.
If a peer is able to support the optional credit-windowing extension
then it MUST include an Extensions Supported data item (Section 9.6)
including the value 1, from Table 4, in the appropriate Session
Initialization (Section 8.3) and Session Initialization Response
(Section 8.4) message.
10.1. Credit-Windowing Messages
The credit-windowing extension introduces no additional DLEP signals
or messages. However, if a peer has advertised during session
initialization that it supports the credit-windowing extension then
the following DLEP messages MAY contain additional credit-windowing
data items:
10.1.1. Destination Up Message
The Destination Up message MAY contain one of each of the following
data items:
o Credit Grant (Section 10.2.1)
If the Destination Up message does not contain the Credit Grant data
item, credits MUST NOT be used for that destination.
10.1.2. Destination Up Response Message
If the corresponding Destination Up message contained the Credit
Grant data item, the Destination Up Response message MUST contain one
of each of the following data items:
o Credit Window Status (Section 10.2.2)
10.1.3. Destination Update Message
If the corresponding Destination Up message contained the Credit
Grant data item, the Destination Update message MUST contain one of
each of the following data items:
o Credit Window Status (Section 10.2.2)
If the corresponding Destination Up message contained the Credit
Grant data item, the Destination Update message MAY contain one of
each of the following data items:
o Credit Grant (Section 10.2.1)
o Credit Request (Section 10.2.3)
10.2. Credit-Windowing Data Items
The credit-windowing extension introduces 3 additional data items.
If a peer has advertised during session initialization that it
supports the credit-windowing extension then it MUST correctly
process the following data items:
+------------+------------------------------------------------------+
| Type Code | Description |
+------------+------------------------------------------------------+
| 22 | Credit Grant (Section 10.2.1) |
| 23 | Credit Window Status (Section 10.2.2) |
| 24 | Credit Request (Section 10.2.3) |
+------------+------------------------------------------------------+
10.2.1. Credit Grant
The Credit Grant data item is sent from a DLEP participant to grant
an increment to credits on a window. The Credit Grant data item MAY
appear in the Destination Up (Section 8.9) and Destination Update
(Section 8.13) messages. The value in a Credit Grant data item
represents an increment to be added to any existing credits available
on the window. Upon successful receipt and processing of a Credit
Grant data item, the receiver MUST respond with a message containing
a Credit Window Status data item to report the updated aggregate
values for synchronization purposes, and if initializing a new credit
window, granting initial credits.
When DLEP peers desire to employ the credit-windowing extension, the
peer originating the Destination Up message MUST supply an initial,
non-zero value as the credit increment of the receive window it
controls (i.e., the Modem Receive Window, or Router Receive Window).
When receiving a Credit Grant data item on a Destination Up message,
the receiver MUST take one of the following actions:
1. Reject the use of credits for this destination, via the
Destination Up Response message containing a Status data item
(Section 9.1) with a status code of 'Request Denied'. (See
Table 3), or
2. Initialize the appropriate window value of zero, then apply the
increment specified in the Credit Grant data item.
If the initialization completes successfully, the receiver MUST
respond to the Destination Up message with a Destination Up Response
message that contains a Credit Window Status data item, initializing
its receive window.
The Credit Grant 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit Increment :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Credit Increment |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 22
Length: 8
Reserved: A 64-bit unsigned integer representing the additional
credits to be assigned to the credit window.
Since credits can only be granted by the receiver on a window, the
applicable credit window (either the MRW or the RRW) is derived from
the sender of the grant. The Credit Increment MUST NOT cause the
window to overflow; if this condition occurs, implementations MUST
set the credit window to the maximum value contained in a 64-bit
quantity.
10.2.2. Credit Window Status
If the credit-window extension is supported by the DLEP participants
(both the router and the modem), the Credit Window Status data item
MUST be sent by the participant receiving a Credit Grant for a given
destination.
The Credit Window Status 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Modem Receive Window Value :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Modem Receive Window Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router Receive Window Value :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Router Receive Window Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 23
Length: 16
Modem Receive Window Value: A 64-bit unsigned integer, indicating
the current number of credits available on the Modem Receive
Window, for the destination referred to by the message.
Router Receive Window Value: A 64-bit unsigned integer, indicating
the current number of credits available on the Router Receive
Window, for the destination referred to by the message.
10.2.3. Credit Request
The Credit Request data item MAY be sent from either DLEP
participant, via the Destination Update message (Section 8.13), to
indicate the desire for the partner to grant additional credits in
order for data transfer to proceed on the session. If the
corresponding Destination Up message (Section 8.9) for this session
did not contain a Credit Window Status data item, indicating that
credits are to be used on the session, then the Credit Request data
item MUST be silently dropped by the receiver.
The Credit Request 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 24
Length: 0
11. Security Considerations 11. Security Considerations
The potential security concerns when using DLEP are: The potential security concerns when using DLEP are:
1. DLEP peers may be 'spoofed' by an attacker, either at DLEP 1. DLEP peers may be 'spoofed' by an attacker, either at DLEP
session initialization, or by injection of messages once a session initialization, or by injection of 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 peer to inappropriately alter its information base receiving peer to inappropriately alter its information base
concerning network status. concerning network status.
If the modem and router are separated by more than a single hop, If the modem and router are separated by more than a single hop,
session messages could be altered in order to subvert the behaviour session messages could be altered in order to subvert the behaviour
of either or both DLEP participants. Under these circumstances, the of either or both DLEP participants. Under these circumstances, DLEP
use of [TLS] is strongly RECOMMENDED. However, if both devices are participants MUST implement TLS [RFC5246].
directly physically connected, or exist within an externally secured
private network then an implementation MAY choose not to use TLS.
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 peers that persistently fail Session information base of peers that persistently fail Session
initialization having provided an acceptable Discovery signal, and Initialization having provided an acceptable Discovery signal, and
ignore discovery signals from such peers. ignore Peer Discovery signals from such peers.
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.
12. IANA Considerations 12. IANA Considerations
This section specifies requests to IANA. This section specifies requests to IANA.
12.1. Registrations 12.1. Registrations
skipping to change at page 57, line 9 skipping to change at page 54, line 46
A new repository for DLEP extensions must be created. A new repository for DLEP extensions must be created.
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 (Section 10) | | 1 | Credit Windowing |
| 2-65519 | Reserved for future extensions | | 2-65519 | Reserved 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 4: DLEP Extension types
12.7. DLEP Well-known Port 12.7. DLEP Well-known Port
It is requested that IANA allocate a well-known port number for DLEP It is requested that IANA allocate a single well-known port number
communication. for both TCP and UDP, for DLEP communication. SCTP port allocation
is not required.
12.8. DLEP Multicast Address 12.8. DLEP IPv6 Link-local Multicast Address
It is requested that IANA allocate a multicast address for DLEP It is requested that IANA allocate an IPv6 link-local multicast
discovery signals. address for DLEP discovery signals.
13. 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 and Victoria Mercieca. Vikram Kaul, Nelson Powell and Victoria Mercieca.
14. References 14. References
14.1. Normative References 14.1. Normative References
[CREDIT] Ratliff, S., "Credit Windowing extension for DLEP", draft-
ietf-manet-credit-window-00 IETF draft, October 2015.
[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, DOI 10.17487/ Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997, RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
14.2. Informative References 14.2. Informative References
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/ (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/
RFC5246, August 2008, RFC5246, August 2008,
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