draft-ietf-manet-dlep-17.txt   draft-ietf-manet-dlep-18.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 S. Jury
Expires: April 17, 2016 Expires: August 7, 2016 Cisco Systems
S. Jury
Cisco Systems
D. Satterwhite D. Satterwhite
Broadcom Broadcom
R. Taylor R. Taylor
Airbus Defence & Space Airbus Defence & Space
October 16, 2015 B. Berry
February 4, 2016
Dynamic Link Exchange Protocol (DLEP) Dynamic Link Exchange Protocol (DLEP)
draft-ietf-manet-dlep-17 draft-ietf-manet-dlep-18
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-
skipping to change at page 1, line 44 skipping to change at page 1, line 43
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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 April 17, 2016. This Internet-Draft will expire on August 7, 2016.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Protocol Overview . . . . . . . . . . . . . . . . . . . . 7 1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 7
1.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 8 2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 7
2. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.1. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 9
3. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3. Destinations . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1. Mandatory Metrics . . . . . . . . . . . . . . . . . . . . 9 3.1. Router-requested Destinations . . . . . . . . . . . . . . 10
4. DLEP Signal and Message Processing . . . . . . . . . . . . . 10 4. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
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 . . . . . . . . . . . . . . 14
5.3. In-Session State . . . . . . . . . . . . . . . . . . . . 14 5.3. In-Session State . . . . . . . . . . . . . . . . . . . . 15
5.3.1. Heartbeats . . . . . . . . . . . . . . . . . . . . . 15 5.3.1. Heartbeats . . . . . . . . . . . . . . . . . . . . . 16
5.4. Session Termination State . . . . . . . . . . . . . . . . 15 5.4. Session Termination State . . . . . . . . . . . . . . . . 16
6. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 16 5.5. Session Reset state . . . . . . . . . . . . . . . . . . . 17
6.1. Experiments . . . . . . . . . . . . . . . . . . . . . . . 17 5.5.1. Unexpected TCP connection termination . . . . . . . . 17
7. Scalability . . . . . . . . . . . . . . . . . . . . . . . . . 17 6. Transaction Model . . . . . . . . . . . . . . . . . . . . . . 17
8. DLEP Signal and Message Structure . . . . . . . . . . . . . . 17 7. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 18
8.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 18 7.1. Experiments . . . . . . . . . . . . . . . . . . . . . . . 18
8.2. DLEP Message Header . . . . . . . . . . . . . . . . . . . 19 8. Scalability . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.3. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 19 9. DLEP Signal and Message Structure . . . . . . . . . . . . . . 19
9. DLEP Signals and Messages . . . . . . . . . . . . . . . . . . 20 9.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 20
9.1. Peer Discovery Signal . . . . . . . . . . . . . . . . . . 21 9.2. DLEP Message Header . . . . . . . . . . . . . . . . . . . 20
9.2. Peer Offer Signal . . . . . . . . . . . . . . . . . . . . 22 9.3. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 21
9.3. Session Initialization Message . . . . . . . . . . . . . 22 10. DLEP Signals and Messages . . . . . . . . . . . . . . . . . . 21
9.4. Session Initialization Response Message . . . . . . . . . 23 10.1. Peer Discovery Signal . . . . . . . . . . . . . . . . . 22
9.5. Session Update Message . . . . . . . . . . . . . . . . . 25 10.2. Peer Offer Signal . . . . . . . . . . . . . . . . . . . 23
9.6. Session Update Response Message . . . . . . . . . . . . . 26 10.3. Session Initialization Message . . . . . . . . . . . . . 23
9.7. Session Termination Message . . . . . . . . . . . . . . . 26 10.4. Session Initialization Response Message . . . . . . . . 24
9.8. Session Termination Response Message . . . . . . . . . . 27 10.5. Session Update Message . . . . . . . . . . . . . . . . . 26
9.9. Destination Up Message . . . . . . . . . . . . . . . . . 27 10.6. Session Update Response Message . . . . . . . . . . . . 27
9.10. Destination Up Response Message . . . . . . . . . . . . . 28 10.7. Session Termination Message . . . . . . . . . . . . . . 28
9.11. Destination Down Message . . . . . . . . . . . . . . . . 29 10.8. Session Termination Response Message . . . . . . . . . . 28
9.12. Destination Down Response Message . . . . . . . . . . . . 29 10.9. Destination Up Message . . . . . . . . . . . . . . . . . 28
9.13. Destination Update Message . . . . . . . . . . . . . . . 30 10.10. Destination Up Response Message . . . . . . . . . . . . 30
9.14. Heartbeat Message . . . . . . . . . . . . . . . . . . . . 31 10.11. Destination Announce Message . . . . . . . . . . . . . . 30
9.15. Link Characteristics Request Message . . . . . . . . . . 31 10.12. Destination Announce Response Message . . . . . . . . . 31
9.16. Link Characteristics Response Message . . . . . . . . . . 32 10.13. Destination Down Message . . . . . . . . . . . . . . . . 32
10. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 33 10.14. Destination Down Response Message . . . . . . . . . . . 32
10.1. Status . . . . . . . . . . . . . . . . . . . . . . . . . 34 10.15. Destination Update Message . . . . . . . . . . . . . . . 33
10.2. IPv4 Connection Point . . . . . . . . . . . . . . . . . 37 10.16. Heartbeat Message . . . . . . . . . . . . . . . . . . . 34
10.3. IPv6 Connection Point . . . . . . . . . . . . . . . . . 38 10.17. Link Characteristics Request Message . . . . . . . . . . 35
10.4. Peer Type . . . . . . . . . . . . . . . . . . . . . . . 39 10.18. Link Characteristics Response Message . . . . . . . . . 35
10.5. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 40 11. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 37
10.6. Extensions Supported . . . . . . . . . . . . . . . . . . 40 11.1. Status . . . . . . . . . . . . . . . . . . . . . . . . . 38
10.7. MAC Address . . . . . . . . . . . . . . . . . . . . . . 41 11.2. IPv4 Connection Point . . . . . . . . . . . . . . . . . 40
10.8. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 42 11.3. IPv6 Connection Point . . . . . . . . . . . . . . . . . 41
10.9. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 43 11.4. Peer Type . . . . . . . . . . . . . . . . . . . . . . . 42
10.10. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 44 11.5. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 43
10.11. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 45 11.6. Extensions Supported . . . . . . . . . . . . . . . . . . 43
10.12. Maximum Data Rate (Receive) . . . . . . . . . . . . . . 46 11.7. MAC Address . . . . . . . . . . . . . . . . . . . . . . 44
10.13. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 46 11.8. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 45
10.14. Current Data Rate (Receive) . . . . . . . . . . . . . . 47 11.9. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 46
10.15. Current Data Rate (Transmit) . . . . . . . . . . . . . . 48 11.10. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 47
10.16. Latency . . . . . . . . . . . . . . . . . . . . . . . . 49 11.11. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 48
10.17. Resources (Receive) . . . . . . . . . . . . . . . . . . 50 11.12. Maximum Data Rate (Receive) . . . . . . . . . . . . . . 49
10.18. Resources (Transmit) . . . . . . . . . . . . . . . . . . 50 11.13. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 49
10.19. Relative Link Quality (Receive) . . . . . . . . . . . . 51 11.14. Current Data Rate (Receive) . . . . . . . . . . . . . . 50
10.20. Relative Link Quality (Transmit) . . . . . . . . . . . . 52 11.15. Current Data Rate (Transmit) . . . . . . . . . . . . . . 51
11. Security Considerations . . . . . . . . . . . . . . . . . . . 52 11.16. Latency . . . . . . . . . . . . . . . . . . . . . . . . 52
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 53 11.17. Resources (Receive) . . . . . . . . . . . . . . . . . . 52
12.1. Registrations . . . . . . . . . . . . . . . . . . . . . 53 11.18. Resources (Transmit) . . . . . . . . . . . . . . . . . . 53
12.2. Expert Review: Evaluation Guidelines . . . . . . . . . . 54 11.19. Relative Link Quality (Receive) . . . . . . . . . . . . 54
12.3. Signal/Message Type Registration . . . . . . . . . . . . 54 11.20. Relative Link Quality (Transmit) . . . . . . . . . . . . 54
12.4. DLEP Data Item Registrations . . . . . . . . . . . . . . 54 11.21. Maximum Transmission Unit (MTU) . . . . . . . . . . . . 55
12.5. DLEP Status Code Registrations . . . . . . . . . . . . . 54 12. Security Considerations . . . . . . . . . . . . . . . . . . . 56
12.6. DLEP Extensions Registrations . . . . . . . . . . . . . 54 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 56
12.7. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 55 13.1. Registrations . . . . . . . . . . . . . . . . . . . . . 56
12.8. DLEP IPv6 Link-local Multicast Address . . . . . . . . . 55 13.2. Signal/Message Type Registration . . . . . . . . . . . . 57
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 55 13.3. DLEP Data Item Registrations . . . . . . . . . . . . . . 57
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 55 13.4. DLEP Status Code Registrations . . . . . . . . . . . . . 57
14.1. Normative References . . . . . . . . . . . . . . . . . . 55 13.5. DLEP Extensions Registrations . . . . . . . . . . . . . 58
14.2. Informative References . . . . . . . . . . . . . . . . . 55 13.6. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 58
Appendix A. Discovery Signal Flows . . . . . . . . . . . . . . . 56 13.7. DLEP IPv4 Link-local Multicast Address . . . . . . . . . 58
Appendix B. Peer Level Message Flows . . . . . . . . . . . . . . 56 13.8. DLEP IPv6 Link-local Multicast Address . . . . . . . . . 58
B.1. Session Initialization . . . . . . . . . . . . . . . . . 56 14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 58
B.2. Session Initialization - Refused . . . . . . . . . . . . 57 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 59
B.3. Router Changes IP Addresses . . . . . . . . . . . . . . . 57 15.1. Normative References . . . . . . . . . . . . . . . . . . 59
B.4. Modem Changes Session-wide Metrics . . . . . . . . . . . 57 15.2. Informative References . . . . . . . . . . . . . . . . . 59
B.5. Router Terminates Session . . . . . . . . . . . . . . . . 58 Appendix A. Discovery Signal Flows . . . . . . . . . . . . . . . 59
B.6. Modem Terminates Session . . . . . . . . . . . . . . . . 58 Appendix B. Peer Level Message Flows . . . . . . . . . . . . . . 60
B.7. Session Heartbeats . . . . . . . . . . . . . . . . . . . 59 B.1. Session Initialization . . . . . . . . . . . . . . . . . 60
B.8. Router Detects a Heartbeat timeout . . . . . . . . . . . 60 B.2. Session Initialization - Refused . . . . . . . . . . . . 61
B.9. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 61 B.3. Router Changes IP Addresses . . . . . . . . . . . . . . . 61
Appendix C. Destination Specific Signal Flows . . . . . . . . . 61 B.4. Modem Changes Session-wide Metrics . . . . . . . . . . . 61
C.1. Common Destination Signaling . . . . . . . . . . . . . . 61 B.5. Router Terminates Session . . . . . . . . . . . . . . . . 62
C.2. Multicast Destination Signaling . . . . . . . . . . . . . 62 B.6. Modem Terminates Session . . . . . . . . . . . . . . . . 62
C.3. Link Characteristics Request . . . . . . . . . . . . . . 62 B.7. Session Heartbeats . . . . . . . . . . . . . . . . . . . 63
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 63 B.8. Router Detects a Heartbeat timeout . . . . . . . . . . . 64
B.9. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 65
Appendix C. Destination Specific Message Flows . . . . . . . . . 65
C.1. Common Destination Notification . . . . . . . . . . . . . 65
C.2. Multicast Destination Notification . . . . . . . . . . . 66
C.3. Link Characteristics Request . . . . . . . . . . . . . . 67
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 68
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
skipping to change at page 4, line 48 skipping to change at page 5, line 5
In addition to utilizing variable datarate links, mobile networks are In addition to utilizing variable datarate links, mobile networks are
challenged by the notion that link connectivity will come and go over challenged by the notion that link connectivity will come and go over
time, without an effect on a router's interface state (Up or Down). time, without an effect on a router's interface state (Up or Down).
Effectively utilizing a relatively short-lived connection is Effectively utilizing a relatively short-lived connection is
problematic in IP routed networks, as routing protocols tend to rely problematic in IP routed networks, as routing protocols tend to rely
on interface state and independent timers at OSI Layer 3 to maintain on interface state and independent timers at OSI Layer 3 to maintain
network convergence (e.g., HELLO messages and/or recognition of DEAD network convergence (e.g., HELLO messages and/or recognition of DEAD
routing adjacencies). These dynamic connections can be better routing adjacencies). These dynamic connections can be better
utilized with an event-driven paradigm, where acquisition of a new utilized with an event-driven paradigm, where acquisition of a new
neighbor (or loss of an existing one) is signaled, as opposed to a neighbor (or loss of an existing one) is signaled, as opposed to a
paradigm driven by timers and/or interface state. paradigm driven by timers and/or interface state. DLEP not only
implements such an event-driven paradigm, but does so over a local (1
hop) TCP session, which guarantees delivery of the event messages.
Another complicating factor for mobile networks are the different Another complicating factor for mobile networks are the different
methods of physically connecting the modem devices to the router. methods of physically connecting the modem devices to the router.
Modems can be deployed as an interface card in a router's chassis, or Modems can be deployed as an interface card in a router's chassis, or
as a standalone device connected to the router via Ethernet or serial as a standalone device connected to the router via Ethernet or serial
link. In the case of Ethernet attachment, with existing protocols link. In the case of Ethernet attachment, with existing protocols
and techniques, routing software cannot be aware of convergence and techniques, routing software cannot be aware of convergence
events occurring on the radio link (e.g., acquisition or loss of a events occurring on the radio link (e.g., acquisition or loss of a
potential routing neighbor), nor can the router be aware of the potential routing neighbor), nor can the router be aware of the
actual capacity of the link. This lack of awareness, along with the actual capacity of the link. This lack of awareness, along with the
variability in datarate, leads to a situation where finding the variability in datarate, leads to a situation where finding the
(current) best route through the network to a given destination is (current) best route through the network to a given destination is
difficult to establish and properly maintain. This is especially difficult to establish and properly maintain. This is especially
skipping to change at page 6, line 23 skipping to change at page 7, line 6
Figure 2 shows how DLEP can support a configuration where routers are Figure 2 shows how DLEP can support a configuration where routers are
connected with different link types. In this example, Modem A connected with different link types. In this example, Modem A
implements a point-to-point link, and Modem B is connected via a implements a point-to-point link, and Modem B is connected via a
shared medium. In both cases, the DLEP protocol is used to report shared medium. In both cases, the DLEP protocol is used to report
the characteristics of the link (datarate, latency, etc.) to routers. the characteristics of the link (datarate, latency, etc.) to routers.
The modem is also able to use the DLEP session to notify the router The modem is also able to use the DLEP session to notify the router
when the remote node is lost, shortening the time required to re- when the remote node is lost, shortening the time required to re-
converge the network. converge the network.
+--------+ +--------+ +--------+ +--------+
+----+ Modem A| | Modem A+---+ +----+ Modem | | Modem +---+
| | Device | <===== // ======> | Device | | | | Device | | Device |
| | Type A | <===== // ======> | Type A | |
| +--------+ P-2-P Link +--------+ | | +--------+ P-2-P Link +--------+ |
+---+----+ +---+----+ +---+----+ +---+----+
| Router | | Router | | Router | | Router |
| | | | | | | |
+---+----+ +---+----+ +---+----+ +---+----+
| +--------+ +--------+ | | +--------+ +--------+ |
+-----+ Modem B| | Modem B| | +-----+ Modem | | Modem | |
| Device | o o o o o o o o | Device +--+ | Device | o o o o o o o o | Device +--+
+--------+ o Shared o +--------+ | Type B | o Shared o | Type B |
o Medium o +--------+ o Medium o +--------+
o o o o
o o o o
o o o o
o o
+--------+ +--------+
| Modem B| | Modem |
| Device | | Device |
| Type B |
+---+----+ +---+----+
| |
| |
+---+----+ +---+----+
| Router | | Router |
| | | |
+--------+ +--------+
Figure 2: DLEP Network with Multiple Modem Devices Figure 2: DLEP Network with Multiple Modem Devices
1.1. Protocol Overview 1.1. Requirements
As mentioned earlier, DLEP defines a set of messages used by modems The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
and their attached routers. The messages are used to communicate "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
events that occur on the physical link(s) managed by the modem: for "OPTIONAL" in this document are to be interpreted as described in BCP
example, a remote node entering or leaving the network, or that the 14, RFC 2119 [RFC2119].
link has changed. Associated with these messages are a set of data
items - information that describes the remote node (e.g., address 2. Protocol Overview
information), and/or the characteristics of the link to the remote
node. DLEP defines a set of messages used by modems and their attached
routers to communicate 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 link has changed. Associated with these
messages are a set of Data Items - information that describes the
remote node (e.g., address information), and/or the characteristics
of the link to the remote node. Throughout this document, we refer
to a modems/routers participating in a DLEP session as 'DLEP Peers',
unless a specific distinction (e.g. modem or router) is required.
DLEP uses a session-oriented paradigm between the modem device and DLEP uses a session-oriented paradigm between the modem device and
its associated router. If multiple modem devices are attached to a its associated router. If multiple modem devices are attached to a
router (as in Figure 2), or the modem supports multiple connections router (as in Figure 2), or the modem supports multiple connections
(via multiple logical or physical interfaces), then separate DLEP (via multiple logical or physical interfaces), then separate DLEP
sessions exist for each modem or connection. A router and modem form sessions exist for each modem or connection. A router and modem form
a session by completing the discovery and initialization process. a session by completing the discovery and initialization process.
This router-modem session persists unless or until it either (1) This router-modem session persists unless or until it either (1)
times out, based on a heartbeat, or (2) is explicitly torn down by times out, based on the absence of traffic (including heartbeats), or
one of the participants. (2) is explicitly torn down by one of the participants.
The router/modem session provides a carrier for information exchange The router/modem session provides a carrier for information exchange
concerning 'destinations' that are available via the modem device. concerning 'destinations' that are available via the modem device.
Destinations can be identified by either the router or the modem, and Destinations can be identified by either the router or the modem, and
represent a specific, addressable location (e.g., an address) that represent a specific, addressable location that can be reached via
can be reached via the link(s) managed by the modem. A destination the link(s) managed by the modem. A destination can be either
can be either physical or logical. physical or logical.
The example of a physical destination would be that of a remote, far- The example of a physical destination would be that of a remote, far-
end router attached via the variable-quality network. As for a end router attached via the variable-quality network.
logical destination, the best example is that of Multicast.
Multicast traffic destined for the variable-quality network (the The example of a logical destination is Multicast. Multicast traffic
network accessed via the DLEP modem) is handled in IP networks by destined for the variable-quality network (the network accessed via
deriving a Layer 2 MAC address based on the Layer 3 address. the modem) is handled in IP networks by deriving a Layer 2 MAC
Leveraging on this scheme, multicast traffic is supported in DLEP address based on the Layer 3 address. Leveraging on this scheme,
simply by treating the derived MAC address as any other destination multicast traffic is supported in DLEP simply by treating the derived
(albeit a logical one) in the network. To support these logical MAC address as any other destination in the network. To support
destinations, one of the DLEP participants (typically, the router) these logical destinations, one of the DLEP participants (typically,
informs the other as to the existence of the logical destination. the router) informs the other as to the existence of the logical
The modem, once it is aware of the existence of this logical destination. The modem, once it is aware of the existence of this
destination, reports link characteristics just as it would for any logical destination, reports link characteristics just as it would
other destination in the network. The specific algorithms a modem for any other destination in the network. The specific algorithms a
would use to derive metrics on multicast (or logical) destinations modem would use to derive metrics on logical destinations are outside
are outside the scope of this specification, and is left to specific 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 The DLEP messages concerning destinations thus become the way for
routers and modems to maintain, and notify each other about, an routers and modems to maintain, and notify each other about, an
information base representing the physical and logical (e.g., information base representing the physical and logical destinations
multicast) destinations accessible via the modem device, as well as accessible via the modem device, as well as the link characteristics
the link characteristics to those destinations. to those destinations.
1.2. Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", While this document represents the best efforts of the working group
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and to be functionally complete, it is recognized that extensions to DLEP
"OPTIONAL" in this document are to be interpreted as described in BCP will in all likelihood be necessary as more link types are used.
14, RFC 2119 [RFC2119]. Such extensions are defined as additional rules of behavior,
messages, data items and/or status codes that are not defined in this
document. DLEP contains a standard mechanism for router and modem
implementations to negotiate the available extensions to use on a
per-session basis.
2. Assumptions 2.1. Assumptions
DLEP specifies UDP multicast for single-hop discovery signalling, and DLEP specifies UDP multicast for single-hop discovery signaling, and
TCP for transport of the control messages. Therefore, DLEP assumes TCP for transport of the control messages. Therefore, DLEP assumes
that the modem and router have topologically consistent IP addresses 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. Other reliable transports for the protocol are possible, assignment. DLEP relies on the guaranteed- delivery of its messages
but are outside the scope of this document. between router and modem, once the 1 hop discovery process is
complete, hence, the specification of TCP to carry the messages.
Other reliable transports for the protocol are possible, but are
outside the scope of this document.
DLEP assumes that the MAC address for delivering data traffic is the DLEP assumes that the MAC address for delivering data traffic is the
MAC address used by DLEP to identify the destination. No MAC address used by DLEP to identify the destination. No
manipulation or substitution is performed; the MAC address supplied manipulation or substitution is performed; the MAC address supplied
in a Destination Up message (Section 9.9) message is used as the OSI in all destination messages is used as the OSI Layer 2 Destination
Layer 2 Destination MAC address. DLEP also assumes that MAC MAC address. DLEP also assumes that MAC addresses are unique within
addresses are unique within the context of a router-modem session. the context of a router-modem session.
DLEP assumes that security on the session (e.g., authentication of The reliance on MAC addresses by DLEP forces the assumption that
session partners, encryption of traffic, or both) is dealt with by participating DLEP peers are on a single segment (either physical or
the underlying transport mechanism (e.g., by using a transport such logically, via tunneling protocols) at Layer 2. DLEP further assumes
as TLS [RFC5246]). that security of the implementations (e.g., authentication of
stations, encryption of traffic, or both) is dealt with by by
utilizing Layer 2 security techniques. This reliance on Layer 2
mechanisms secures all DLEP messages - both the UDP discovery
messages and the TCP control messages.
3. Metrics 3. Destinations
Destination messages describe the acquisition and loss of network
destinations, and control the flow of information about the
destinations in the several ways. A destination MUST contain a MAC
address; it MAY optionally include a Layer 3 address (or multiple
addresses). The MAC address MAY reference a logical destination, as
in a derived multicast MAC address, as well as a physical device. As
destinations are discovered, DLEP routers and modems build an
information base of destinations accessible via the modem.
DLEP can support MAC addresses in either EUI-48 or EUI-64 format,
with the restriction that all MAC addresses for a given DLEP session
MUST be in the same format, and MUST be consistent with the MAC
address format of the connected modem (e.g., if the modem is
connected to the router with an EUI-48 MAC, all destination addresses
via that modem MUST be expressed in EUI-48 format).
Destination messages trigger creation/maintenance/deletion of
destinations in the information base of the recipient. For example,
a modem will inform its attached router of the presence of a new
destination via the Destination Up message (Section 10.9). Receipt
of a Destination Up causes the router to allocate the necessary
resources, creating an entry in the information base with the
specifics (i.e. MAC Address, Latency, Data Rate, etc.) of the
destination. The loss of a destination is communicated via the
Destination Down message (Section 10.13), and changes in status to
the destination (e.g., varying link quality, or addressing changes)
are communicated via the Destination Update message (Section 10.15).
The information on a given destination will persist in the
implementation's information base until a Destination Down message is
received, indicating that the peer has lost contact or interest with
the remote node, or the implementation transitions to the Session
Termination state.
3.1. Router-requested Destinations
Usually a modem will discover the presence of one or more remote
router/modem pairs and announce each destination's arrival by sending
a corresponding Destination Up message to its peer. However, there
may be times when a router wishes to express an interest in the
status of the link to a logical destination that has yet to be
announced, typically a multicast destination. To facilitate this,
DLEP provides the Destination Announce (Section 10.11) and
Destination Announce Response (Section 10.12) messages. These
messages have similar semantics to the Destination Up and Destination
Up Response messages, but flow from router to modem.
After successfully receiving and processing a Destination Announce
message, a modem then announces changes to the link to the logical
destination via Destination Update messages. A modem MAY refuse a
Destination Announce message by replying with a Destination Announce
Response message with a 'Request Denied' status code, see Table 3.
A Destination Announce message MAY also be used by a router to
request information concerning a destination that it has previously
declined interest in, via the 'Not Interested' status code, see
Table 3, or declared as down, via the Destination Down message.
One of the advantages of implementing DLEP is to leverage the modem's
knowledge of the links between remote destinations allowing routers
to avoid using probed neighbor discovery techniques, therefore modem
implementations SHOULD announce available destinations via the
Destination Up message, rather than relying on Destination Announce
messages.
4. Metrics
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 by a 'best effort', incorporating all
pertinent data that is available to the modem device. pertinent data that is available to the modem device.
DLEP allows for metrics to be sent within two contexts - metrics for DLEP allows for metrics to be sent within two contexts - metrics for
a specific destination within the network (e.g., a specific router), a specific destination within the network (e.g., a specific router),
and per-session (those that apply to all destinations accessed via and per-session (those that apply to all destinations accessed via
the modem). Most metrics can be further subdivided into transmit and the modem). Most metrics can be further subdivided into transmit and
receive metrics. In cases where metrics are provided at session receive metrics. In cases where metrics are provided at session
level, the receiver MUST propagate the metrics to all entries in its level, the router MUST propagate the metrics to all entries in its
information base for destinations that are accessed via the information base for destinations that are accessed via the modem.
originator.
It is left to implementations to choose sensible default values based
on their specific characteristics. Modems having static (non-
changing) link metric characteristics MAY report metrics only once
for a given destination (or once on a modem-wide basis, if all
connections via the modem are of this static nature).
DLEP modem implementations MUST announce all metric items that will DLEP modem implementations MUST announce all metric items that will
be reported during the session, and provide default values for those be reported during the session, and provide default values for those
metrics, in the Session Initialization Response message metrics, in the Session Initialization Response message
(Section 9.4). In order to use a metric type that was not included (Section 10.4). In order to use a metric type that was not included
in the Session Initialization Response message, modem implementations in the Session Initialization Response message, modem implementations
MUST terminate the session with the router (via the Session Terminate MUST terminate the session with the router (via the Session Terminate
message (Section 9.7)), and establish a new session. message (Section 10.7)), and establish a new session. A modem MUST
include the following list of metrics in the Session Initialization
A DLEP participant MAY send metrics both in a session context (via Response message:
the Session Update message) and a specific destination context (via
Destination Update) at any time. The most recently received metric
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.
3.1. Mandatory Metrics
As mentioned above, DLEP modem implementations MUST announce all
supported metric items during the Session Initialization state.
However, a modem MUST include the following list of metrics in the
Session Initialization Response message (Section 9.4):
o Maximum Data Rate (Receive) (Section 10.12)
o Maximum Data Rate (Transmit) (Section 10.13)
o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Transmit) (Section 10.15)
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 o Maximum Data Rate (Receive) (Section 11.12)
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, o Maximum Data Rate (Transmit) (Section 11.13)
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 o Current Data Rate (Receive) (Section 11.14)
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 o Current Data Rate (Transmit) (Section 11.15)
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 o Latency (Section 11.16)
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 A DLEP modem MAY send metrics both in a session context (via the
Session Update message) and a specific destination context (via
Destination Update) at any time. The most recently received metric
value MUST take precedence over any earlier value, regardless of
context - that is:
DLEP defines a simple message transaction model: Only one (1) request 1. If the router receives metrics in a specific destination context
per destination may be in progress at a time. A message transaction (via the Destination Update message), then the specific
is considered complete when a response matching a previously issued destination is updated with the new metric.
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 2. If the router receives metrics in a modem-wide context (via the
of time for some peers to complete, for example a modem handling a Session Update message), then the metrics for all destinations
multicast destination up request may have to perform a complex accessed via the modem MUST be updated with the new metric.
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 It is left to implementations to choose sensible default values based
Initialization message (Section 9.3) may be in progress at a time. on their specific characteristics. Modems having static (non-
As above, a session transaction is considered complete when a changing) link metric characteristics MAY report metrics only once
response matching a previously issued request is received. If a peer for a given destination (or once on a modem-wide basis, if all
receives a session request while there is already a session request connections via the modem are of this static nature).
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 In addition to communicating existing metrics about the link, DLEP
implementation can detect if a peer has failed in some way by use of provides a message allowing a router to request a different datarate
the session heartbeat mechanism during the In-Session state, see or latency from the modem. This message is the Link Characteristics
Section 5.3. Request message (Section 10.17), and gives the router the ability to
deal with requisite increases (or decreases) of allocated datarate/
latency in demand-based schemes in a more deterministic manner.
5. DLEP Session Flow 5. DLEP Session Flow
All DLEP peers transition through four (4) distinct states during the All Peers participating in a DLEP session transition through five (5)
lifetime of a DLEP session: distinct states during the lifetime of a DLEP session:
o Peer Discovery o Peer Discovery
o Session Initialization o Session Initialization
o In-Session o In-Session
o Session Termination o Session Termination
o Session Reset
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 a
one or more preconfigured address/port combinations SHOULD be preconfigured TCP address/port combination MUST be provided to the
provided to the router, and the device starts in the Session router, and the router 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 MUST send UDP packets containing In the Peer Discovery state, if the router implementation supports
a Peer Discovery signal (Section 9.1) to the DLEP well-known IPv6 IPv6, it SHOULD send UDP packets containing a Peer Discovery signal
link-local multicast address (Section 12.8) and port number (Section 10.1) to the DLEP well-known IPv6 link-local multicast
(Section 12.7), setting the packet source address to a valid local address (Section 13.8) and port number (Section 13.6), setting the
IPv6 address and the source port to an unused port in the range 49152 packet source address to a valid IPv6 link-local address and the
to 65535. If the router implementation supports IPv4, then they MAY source port to a valid port number.
also broadcast Peer Discovery signals in UDP packets to the IPv4
broadcast address (255.255.255.255), setting the packet source If the router implementation supports IPv4, it SHOULD send UDP
address to a valid local IPv4 address and the source port to an packets containing a Peer Discovery signal (Section 10.1) to the DLEP
unused port in the range 49152 to 65535. well-known IPv4 link-local multicast address (Section 13.7) and port
number (Section 13.6), setting the packet source address to a valid
local IPv4 address and the source port to a valid port number.
The implementation then waits for a unicast UDP packet containing a The implementation then waits for a unicast UDP packet containing a
Peer Offer signal (Section 9.2) from a potential peer modem. While Peer Offer signal (Section 10.2) from a potential DLEP peer modem.
in the Peer Discovery state, Peer Discovery signals MUST be sent While in the Peer Discovery state, Peer Discovery signals MUST be
repeatedly by a router, at regular intervals; every three (3) seconds sent repeatedly by a DLEP router, at regular intervals. The interval
with some jitter is RECOMMENDED. MUST be a minimum of one second; it SHOULD be a configurable
parameter. Note that this operation (sending Peer Discovery and
waiting for Peer Offer) is outside the DLEP Transaction Model, as the
Transaction Model only describes messages on a TCP session.
In the Peer Discovery state, the modem waits for incoming Peer In the Peer Discovery state, the DLEP modem implementation MUST
Discovery signals on the DLEP well-known multicast address and port. listen for incoming Peer Discovery signals on the DLEP well-known
On receipt of a valid signal, it MUST unicast a Peer Offer signal to link-local multicast address and port. The choice of using the well-
the source address and port of the received UDP packet. Peer Offer known IPv4 or the IPv6 well- known link-local multicast address and
signals MAY contain the unicast address and port for TCP-based port MUST be made by configuration. On receipt of a valid Peer
communication with a modem, via the IPv4 Connection Point data item Discovery signal, it MUST unicast a Peer Offer signal to the source
(Section 10.2) or the IPv6 Connection Point data item (Section 10.3), address and port of the received UDP packet. Peer Offer signals MAY
contain one or more unicast address/port combinations for TCP-based
communication with the modem, via the IPv4 Connection Point data item
(Section 11.2) or the IPv6 Connection Point data item (Section 11.3),
on which it is prepared to accept an incoming TCP connection. If the on which it is prepared to accept an incoming TCP connection. If the
modem does not include an IPv4 Connection Point data item, nor a IPv6 modem does not include an IPv4 Connection Point data item, nor a IPv6
Connection Point data item, then the source address of the packet Connection Point data item, then the source address of the packet
containing the Peer Offer signal MUST be set to the address on which containing the Peer Offer signal MUST be used as the address on which
the modem is willing to accept TCP connections. the modem is willing to accept TCP connections.
The modem then begins listening for incoming TCP connections, and, Upon establishment of a TCP connection, both modem and router enter
having accepted one, enters the Session Initialization state. the Session Initialization state. Anything other than Peer Discovery
Anything other than Peer Discovery signals received on the UDP socket signals received on the UDP socket MUST be silently dropped.
MUST be silently dropped.
Modems SHOULD be prepared to accept a TCP connection from a router Modems MUST be prepared to accept a TCP connection from a router that
that is not using the Discovery mechanism, i.e. a connection attempt is not using the Discovery mechanism, i.e. a connection attempt that
that occurs without a preceding Peer Discovery signal. The modem occurs without a preceding Peer Discovery signal.
MUST accept a TCP connection on only one (1) address/port combination
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. It is RECOMMENDED that an implementation attempt to connect tried. It is RECOMMENDED that an implementation attempt to connect
to any announced IPv6 address/port combinations before attempting to to any announced IPv6 address/port combinations before attempting to
use IPv4 combinations. If a TCP connection cannot be achieved using use IPv4 combinations. If a TCP connection cannot be achieved using
any of the address/port combinations and the Discovery mechanism is any of the address/port combinations and the Discovery mechanism is
skipping to change at page 13, line 32 skipping to change at page 14, line 20
data items are included in the Peer Offer signal, the router MUST use 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 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 9.3) to the modem. The Session Initialization message (Section 10.3) 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 9.4) from the modem. Receipt of the Response message (Section 10.4) 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 10.1) with value 'Success', see Table 3, indicates that the (Section 11.1) 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 of a Session Initialization message, the modem MUST send a
the modem MUST send a Session Initialization Response message, and Session Initialization Response message, and the session MUST
the session MUST transition to the In-Session state. transition to the In-Session state.
DLEP provides an extension negotiation capability to be used in the DLEP provides an extension negotiation capability to be used in the
Session Initialization state, see Section 6. Extensions supported by Session Initialization state, see Section 7. Extensions supported by
an implementation MUST be declared to potential DLEP peers using the an implementation MUST be declared to potential DLEP peers using the
Extensions Supported data item (Section 10.6). Once both peers have Extensions Supported data item (Section 11.6). Once both
exchanged initialization messages, an implementation MUST NOT emit participants have exchanged initialization messages, an
any message, signal, data item or status code associated with an implementation MUST NOT emit any message, signal, data item or status
extension that was not specified in the received initialization code associated with an extension that was not specified in the
message from its peer. 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 9.7) with a relevant status code, e.g. 'Unexpected (Section 10.7) with the 'Unexpected Message' status code, see
Message', see Table 3, and transition to the Session Termination 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 and transition to the
Peer Discovery state. Session Reset state.
As mentioned before, the Session Initialization Response message MUST If an additional metric is to be introduced after the session has
contain metric data items for all metrics that will be used during started, the session between router and modem MUST be terminated and
the session. If an additional metric is to be introduced after the restarted, and the new metric described in the next Session
session has started, the session between router and modem MUST be Initialization Response message.
terminated and restarted, and the new metric described in the next
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 participants, 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 addition to the session messages, the participants will transmit
messages concerning destinations in the network. These messages
trigger creation/maintenance/deletion of destinations in the
information base of the recipient. For example, a modem will inform
its attached router of the presence of a new destination via the
Destination Up message (Section 9.9). Receipt of a Destination Up
causes the router to allocate the necessary resources, creating an
entry in the information base with the specifics (i.e. MAC Address,
Latency, Data Rate, etc.) of the destination. The loss of a
destination is communicated via the Destination Down message
(Section 9.11), and changes in status to the destination (e.g.,
varying link quality, or addressing changes) are communicated via the
Destination Update message (Section 9.13). The information on a
given destination will persist in the router's information base until
(1) a Destination Down message is received, indicating that the modem
has lost contact with the remote node, or (2) the router/modem
transitions to the Session Termination state.
As well as receiving metrics about the link, DLEP provides a message
allowing a router to request a different datarate or latency from the
modem. This message is the Link Characteristics Request message
(Section 9.15), and gives the router the ability to deal with
requisite increases (or decreases) of allocated datarate/latency in
demand-based schemes in a more 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 A peer terminates the session by sending a Session Termination
Termination message (Section 9.7)), or message (Section 10.7)), or,
o The peer terminates the session, indicated by receiving a Session o The peer terminates the session, indicated by receiving a Session
Termination message. Termination message.
The implementation MUST then transition to the Session Termination The peer MUST then transition to the Session Termination state.
Prior to the exchange of Destination Up (Section 10.9) and
Destination Up Response (Section 10.10) messages, or Destination
Announce (Section 10.11) and Destination Announce Response
(Section 10.12) messages, no messages concerning the logical
destination identified by the MAC Address data item (Section 11.7)
may be sent. A peer receiving any message with such an unannounced
destination MUST terminate the session by issuing a Session
Termination message (Section 10.7) with a status code of 'Invalid
Destination', see Table 3, and transition to the Session Termination
state. state.
The router receiving a Destination Up message MAY decline further
messages concerning a given destination by sending a Destination Up
Response with a status code of 'Not Interested'. Modems receiving
such responses MUST NOT send further messages concerning that
destination to the router.
After exchanging Destination Down (Section 10.13) and Destination
Down Response (Section 10.14) messages, no messages concerning the
logical destination identified by the MAC Address data item may be a
sent without previously sending a new Destination Up message. A peer
receiving a message about a destination previously announced as
'down' MUST terminate the session by issuing a Session Termination
message with a status code of 'Invalid Destination' and transition to
the Session Termination state.
5.3.1. Heartbeats 5.3.1. Heartbeats
In order to maintain the In-Session state, periodic Heartbeat In order to maintain the In-Session state, periodic Heartbeat
messages (Section 9.14) MAY be exchanged between router and modem. messages (Section 10.16) MAY be exchanged between router and modem.
These messages are intended to keep the session alive, and to verify These messages are intended to keep the session alive, and to verify
bidirectional connectivity between the two participants. Each DLEP bidirectional connectivity between the two participants.
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 If Heartbeat messages are used, the following processing rules MUST
with no traffic on the router/modem session before terminating the apply:
session by issuing a Session Termination message with a status code
of 'Timed Out', and then transition to the Session Termination state. o Each DLEP peer is responsible for the creation of heartbeat
messages.
o 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).
o DLEP peers SHOULD allow two (2) heartbeat intervals to expire with
no messages from the peer 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 9.7) as the result of sending a Session Termination message (Section 10.7) 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 9.8) from its peer. If Heartbeat messages Response message (Section 10.8) from its peer. If Heartbeat messages
(Section 9.14) are in use, senders SHOULD allow four (4) heartbeat (Section 10.16) 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 the sender of the Session Termination message receives a Session
Termination Response message from its peer, or times out, it MUST
transition to the Session Reset state.
When an implementation enters the Session Termination state having When an implementation enters the Session Termination state having
received a Session Termination message from its peer, it MUST received a Session Termination message from its peer, it MUST
immediately send a Session Termination Response. immediately send a Session Termination Response and transition to the
Session Reset state.
The sender and receiver of a Session Termination message MUST release
all resources allocated for the session, and MUST eliminate all
destinations in the information base accessible via the peer
represented by the session. Destination Down messages (Section 9.11)
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, 5.5. Session Reset state
the device MUST terminate the TCP connection to the peer, and return
to the relevant initial state.
6. Extensions In the Session Reset state the implementation MUST perform the
following actions:
While this document represents the best efforts of the working group o Release all resources allocated for the session.
to be functionally complete, it is recognized that extensions to DLEP
will in all likelihood be necessary as more link types are used. o Eliminate all destinations in the information base accessible via
Such extensions are defined as additional rules of behaviour, the modem represented by the session. Destination Down messages
messages, data items and/or status codes that are not defined in this (Section 10.13) MUST NOT be sent.
document.
o Terminate the TCP connection.
Having completed these actions the implementation SHOULD return to
the relevant initial state: Peer Discovery for modems; either Peer
Discovery or Session Initialization for routers, depending on
configuration.
5.5.1. Unexpected TCP connection termination
If the TCP connection between peers is terminated when a participant
is not in the Session Reset state, the implementation MUST
immediately transition to the Session Reset state.
6. Transaction Model
DLEP defines a simple message transaction model: Only one 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 participant receives a request for a
destination for which there is already an outstanding request, the
implementation MUST terminate the session by issuing a Session
Termination message (Section 10.7) 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 participants 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 session request, e.g. a Session Initialization
message (Section 10.3) 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 participant receives a
session request while there is already a session request in progress,
it 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 10.16) MUST NOT be considered part of a session
transaction.
DLEP transactions do not time out and are not cancellable. An
implementation can detect if its peer has failed in some way by use
of the session heartbeat mechanism during the In-Session state, see
Section 5.3.
7. Extensions
Extensions MUST be negotiated on a per-session basis during session Extensions MUST be negotiated on a per-session basis during session
initialization via the Extensions Supported mechanism. initialization via the Extensions Supported mechanism.
Implementations are not required to support any extension in order to Implementations are not required to support any extension in order to
be considered DLEP compliant. An extension document, describing the be considered DLEP compliant. An extension document, describing the
operation of a credit windowing scheme for flow control, is described operation of a credit windowing scheme for flow control, is described
in [CREDIT]. in [CREDIT].
If interoperable protocol extensions are required, they MUST be If interoperable protocol extensions are required, they MUST be
standardized either as an update to this document, or as an standardized either as an update to this document, or as an
additional stand-alone specification. The requests for IANA- additional stand-alone specification. The requests for IANA-
controlled registries in this document contain sufficient Reserved controlled registries in this document contain sufficient Reserved
space for DLEP signals, messages, data items and status codes to space for DLEP signals, messages, data items and status codes to
accommodate future extensions to the protocol. accommodate future extensions to the protocol.
As multiple protocol extensions MAY be announced during session As multiple protocol extensions MAY be announced during session
initialization, authors of protocol extensions MUST consider the initialization, authors of protocol extensions MUST consider the
interaction of their extension with other published extensions, and interaction of their extension with other published extensions, and
specify any incompatibilities. specify any incompatibilities.
6.1. Experiments 7.1. Experiments
This document requests Private Use numbering space in the DLEP This document requests Private Use numbering space in the DLEP
signal/message, data item and status code registries for experimental signal/message, data item and status code registries for experimental
extensions. The intent is to allow for experimentation with new extensions. The intent is to allow for experimentation with new
signals, messages, data items, and/or status codes, while still signals, messages, data items, and/or status codes, while still
retaining the documented DLEP behavior. retaining the documented DLEP behavior.
Use of the Private Use signals, messages, data items, status codes, Use of the Private Use signals, messages, data items, status codes,
or behaviors MUST be announced as DLEP Extensions, during session or behaviors MUST be announced as DLEP Extensions, during session
initialization, using extension identifiers from the Private Use initialization, using extension identifiers from the Private Use
skipping to change at page 17, line 30 skipping to change at page 19, line 19
Multiple experiments MAY be announced in the Session Initialization Multiple experiments MAY be announced in the Session Initialization
messages. However, use of multiple experiments in a single session messages. However, use of multiple experiments in a single session
could lead to interoperability issues or unexpected results (e.g., could lead to interoperability issues or unexpected results (e.g.,
clashes of experimental signals, messages, data items and/or status clashes of experimental signals, messages, data items and/or status
code types), and is therefore discouraged. It is left to code types), and is therefore discouraged. It is left to
implementations to determine the correct processing path (e.g., a implementations to determine the correct processing path (e.g., a
decision on whether to terminate the session, or to establish a decision on whether to terminate the session, or to establish a
precedence of the conflicting definitions) if such conflicts arise. precedence of the conflicting definitions) if such conflicts arise.
7. Scalability 8. Scalability
The protocol is intended to support thousands of destinations on a The protocol is intended to support thousands of destinations on a
given modem/router pair. At large scale, implementations SHOULD given modem/router pair. At large scale, implementations SHOULD
consider employing techniques to prevent flooding a peer with a large consider employing techniques to prevent flooding a peer with a large
number of messages in a short time. It is recommended that number of messages in a short time. It is recommended that
implementations consider a dampening algorithm to prevent a flapping implementations consider a dampening algorithm to prevent a flapping
device from generating a large number of Destination Up/Destination device from generating a large number of Destination Up/Destination
Down messages, for example. Implementations SHOULD also consider Down messages, for example. Implementations SHOULD also consider
techniques such as a hysteresis to lessen the impact of rapid, minor techniques such as a hysteresis to lessen the impact of rapid, minor
fluctuations in link quality. The specific algorithms to be used for fluctuations in link quality. The specific algorithms to be used for
handling flapping destinations and minor changes in link quality are handling flapping destinations and minor changes in link quality are
outside the scope of this specification. outside the scope of this specification.
8. DLEP Signal and Message Structure 9. 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 20 skipping to change at page 20, line 8
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.
8.1. DLEP Signal Header 9.1. 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 50 skipping to change at page 20, line 38
Length: The length in octets, expressed as a 16-bit unsigned Length: The length in octets, expressed as a 16-bit unsigned
integer, of all of the DLEP data items associated with this integer, of all of the DLEP data items associated with this
signal. This length SHALL NOT include the length of the header signal. This length 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 participant MUST ignore the signal.
8.2. DLEP Message Header 9.2. 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 30 skipping to change at page 21, line 18
Length: The length in octets, expressed as a 16-bit unsigned Length: The length in octets, expressed as a 16-bit unsigned
integer, of all of the DLEP data items associated with this integer, of all of the DLEP data items associated with this
message. This length SHALL NOT include the length of the header message. This length 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 participant MUST issue a Session Termination
(Section 9.7) with a Status data item (Section 10.1) containing the message (Section 10.7) with a Status data item (Section 11.1)
most relevant status code, and transition to the Session Termination containing the most relevant status code, see Table 3, and transition
state. to the Session Termination state.
8.3. DLEP Generic Data Item 9.3. 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 20, line 12 skipping to change at page 21, line 47
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.
9. DLEP Signals and Messages 10. 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:
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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 9.1) | | 1 | Peer Discovery signal (Section 10.1) |
| 2 | Peer Offer signal (Section 9.2) | | 2 | Peer Offer signal (Section 10.2) |
| 3 | Session Initialization message (Section 9.3) | | 3 | Session Initialization message (Section 10.3) |
| 4 | Session Initialization Response message (Section | | 4 | Session Initialization Response message (Section |
| | 9.4) | | | 10.4) |
| 5 | Session Update message (Section 9.5) | | 5 | Session Update message (Section 10.5) |
| 6 | Session Update Response message (Section 9.6) | | 6 | Session Update Response message (Section 10.6) |
| 7 | Session Termination message (Section 9.7) | | 7 | Session Termination message (Section 10.7) |
| 8 | Session Termination Response message (Section 9.8) | | 8 | Session Termination Response message (Section 10.8) |
| 9 | Destination Up message (Section 9.9) | | 9 | Destination Up message (Section 10.9) |
| 10 | Destination Up Response message (Section 9.10) | | 10 | Destination Up Response message (Section 10.10) |
| 11 | Destination Down message (Section 9.11) | | 11 | Destination Down message (Section 10.13) |
| 12 | Destination Down Response message (Section 9.12) | | 12 | Destination Down Response message (Section 10.14) |
| 13 | Destination Update message (Section 9.13) | | 13 | Destination Update message (Section 10.15) |
| 14 | Heartbeat message (Section 9.14) | | 14 | Heartbeat message (Section 10.16) |
| 15 | Link Characteristics Request message (Section 9.15) | | 15 | Link Characteristics Request message (Section |
| | 10.17) |
| 16 | Link Characteristics Response message (Section | | 16 | Link Characteristics Response message (Section |
| | 9.16) | | | 10.18) |
| 17-65519 | Reserved for future extensions | | 17 | Destination Announce message (Section 10.11) |
| 18 | Destination Announce Response message (Section |
| | 10.12) |
| 19-65519 | Reserved for future extensions |
| 65520-65534 | Private Use. Available for experiments | | 65520-65534 | Private Use. Available for experiments |
| 65535 | Reserved | | 65535 | Reserved |
+-------------+-----------------------------------------------------+ +-------------+-----------------------------------------------------+
Table 1: DLEP Signal/Message types Table 1: DLEP Signal/Message types
9.1. Peer Discovery Signal 10.1. 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 DLEP router to discover
modems in the network. The Peer Offer signal (Section 9.2) is DLEP modems in the network. The Peer Offer signal (Section 10.2) is
required to complete the discovery process. Implementations MAY required to complete the discovery process. Implementations MUST
implement their own retransmit heuristics in cases where it is implement their own retransmit heuristics in cases where it is
determined 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 10.4) o Peer Type (Section 11.4)
9.2. Peer Offer Signal 10.2. 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 9.1). valid Peer Discovery signal (Section 10.1).
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 10.4) o Peer Type (Section 11.4)
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 10.2) o IPv4 Connection Point (Section 11.2)
o IPv6 Connection Point (Section 10.3) o IPv6 Connection Point (Section 11.3)
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. router MUST use when connecting the DLEP TCP session. If multiple IP
If multiple IP Connection Point data items are present in the Peer Connection Point data items are present in the Peer Offer signal,
Offer signal, implementations MAY use their own heuristics to select router implementations MAY use their own heuristics to select the
the address to connect to. If no IP Connection Point data items are 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 router 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 13.6) to establish the TCP connection.
9.3. Session Initialization Message 10.3. Session Initialization Message
A Session Initialization message MUST be sent by a router as the A Session Initialization message MUST be sent by a DLEP 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 modem MUST conclude that there is no
that there is no support for extensions in the sender. support for extensions in the router.
Implementations supporting the Heartbeat Interval (Section 10.5) Implementations supporting the Heartbeat Interval (Section 11.5)
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 9.4), and receipt of Session Initialization Response message (Section 10.4),
should therefore implement their own timeout and retry heuristics for and should therefore implement their own timeout and retry heuristics
this message. for 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 10.5) o Heartbeat Interval (Section 11.5)
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 10.4) o Peer Type (Section 11.4)
o Extensions Supported (Section 10.6) o Extensions Supported (Section 11.6)
A Session Initialization message MUST be acknowledged by the receiver A Session Initialization message MUST be acknowledged by the modem
issuing a Session Initialization Response message (Section 9.4). issuing a Session Initialization Response message (Section 10.4).
As an exception to the general rule that an implementation receiving As an exception to the general rule that an implementation receiving
an unrecognized data item in a message terminating the session with an unrecognized data item in a message terminating the session with
an error, see Section 8.2, if a Session Initialization message an error, see Section 9.2, if a Session Initialization message
contains one or more Extension Supported data items announcing contains one or more Extension Supported data items announcing
support for extensions that the implementation does not recognize, support for extensions that the implementation does not recognize,
then the implementation MAY ignore data items it does not recognize. then the implementation MAY ignore data items it does not recognize.
9.4. Session Initialization Response Message 10.4. 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 9.3). The Session a received Session Initialization message (Section 10.3). The
Initialization Response message completes the DLEP session Session Initialization Response message completes the DLEP session
establishment; the sender of the message should transition to the In- establishment; the modem should transition to the In-Session state
Session state when the message is sent, and the receiver should when the message is sent, and the router should transition to the In-
transition to the In-Session state upon receipt (and successful Session state upon receipt of an acceptable Session Initialization
parsing) of an acceptable Session Initialization Response message. 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
DLEP message containing a metric data item not included in the DLEP message containing a metric data item not included in the
Session Initialization Response message MUST be treated as an error, Session Initialization Response message MUST be treated as an error,
resulting in the termination of the DLEP session between router and resulting in the termination of the DLEP session between router and
modem. modem.
If any optional extensions are supported by the modem, they MUST be If any optional extensions are supported by the modem, they MUST be
enumerated in the Extensions Supported data item. If an Extensions enumerated in the Extensions Supported data item. If an Extensions
Supported data item does not exist in a Session Initialization Supported data item does not exist in a Session Initialization
Response message, the receiver of the message MUST conclude that Response message, the router MUST conclude that there is no support
there is no support for extensions in the sender. for extensions in the modem.
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 participants.
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 10.5) o Heartbeat Interval (Section 11.5)
o Maximum Data Rate (Receive) (Section 10.12) o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 10.13) o Maximum Data Rate (Transmit) (Section 11.13)
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 10.16) o Latency (Section 11.16)
The 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 10.17) o Resources (Receive) (Section 11.17)
o Resources (Transmit) (Section 10.18) o Resources (Transmit) (Section 11.18)
o Relative Link Quality (Receive) (Section 10.19) o Relative Link Quality (Receive) (Section 11.19)
o Relative Link Quality (Transmit) (Section 10.20) o Relative Link Quality (Transmit) (Section 11.20)
o Maximum Transmission Unit (MTU) (Section 11.21)
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 10.1) o Status (Section 11.1)
o Peer Type (Section 10.4) o Peer Type (Section 11.4)
o Extensions Supported (Section 10.6) o Extensions Supported (Section 11.6)
A receiver of a Session Initialization Response message without a
Status data item MUST behave as if a Status data item with code
'Success' had been received.
9.5. Session Update Message A router receiving a Session Initialization Response message without
a Status data item MUST behave as if a Status data item with code
'Success' had been received, see Table 3.
A Session Update message MAY be sent by a DLEP peer to indicate local 10.5. Session Update Message
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 A Session Update message MAY be sent by a DLEP participant to
Session Update message to its attached DLEP modems. Also, for indicate local Layer 3 address changes, or metric changes on a modem-
example, a modem that changes its Maximum Data Rate (Receive) for all wide basis. It should be noted that Session Update messages can be
destinations MAY reflect that change via a Session Update message to sent by both routers and modems. For example, addition of an IPv4
its attached router(s). address to the router MAY prompt a Session Update message to its
attached modems. Also, for example, a modem that changes its Maximum
Data Rate (Receive) for all destinations MAY reflect that change via
a Session Update message to its attached router(s).
Concerning Layer 3 addresses: If the modem is capable of 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 9.13) to their local routers with the new (or message (Section 10.15) 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 9.6). message (Section 10.6).
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 DLEP session.
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 10.12) o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 11.13)
o Maximum Data Rate (Transmit) (Section 10.13) o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Transmit) (Section 11.15)
o Current Data Rate (Transmit) (Section 10.15) o Latency (Section 11.16)
o Latency (Section 10.16) The Session Update message MAY contain one of each of the following
data items, if the data item is in use by the session:
o Resources (Receive) (Section 10.17) o Resources (Receive) (Section 11.17)
o Resources (Transmit) (Section 10.18) o Resources (Transmit) (Section 11.18)
o Relative Link Quality (Receive) (Section 10.19)
o Relative Link Quality (Transmit) (Section 10.20) o Relative Link Quality (Receive) (Section 11.19)
o Relative Link Quality (Transmit) (Section 11.20)
o Maximum Transmission Unit (MTU) (Section 11.21)
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 10.8) o IPv4 Address (Section 11.8)
o IPv6 Address (Section 10.9) o IPv6 Address (Section 11.9)
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 9.6). a Session Update Response message (Section 10.6).
9.6. Session Update Response Message 10.6. 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 9.5) was indicate whether a Session Update message (Section 10.5) 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 Status
following data items: (Section 11.1) data item.
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 status code 'Success'
been received. had been received, see Table 3.
9.7. Session Termination Message 10.7. Session Termination Message
A Session Termination message MUST be sent by a DLEP participant when A Session Termination message MUST be sent by a participant when the
the router/modem session needs to be terminated. DLEP session needs to be terminated. It should be noted that Session
Termination messages can be sent by both routers and modems.
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 Status (Section 11.1)
following data items: data item.
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 data item with status code 'Success',
Termination' has been received. see Table 3, implying graceful termination, had 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 9.8). issuing a Session Termination Response message (Section 10.8).
9.8. Session Termination Response Message 10.8. 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
response to a received Session Termination message (Section 9.7). participant in response to a received Session Termination message
(Section 10.7).
Receipt of a Session Termination Response message completes the Receipt of a Session Termination Response message completes the tear-
teardown of the router/modem session. down of the DLEP 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 Status
the following data items: (Section 11.1) data item.
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', see Table 3, implying graceful termination, had been
received.
9.9. Destination Up Message
A Destination Up message can be sent either by the modem, to indicate 10.9. Destination Up Message
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
group) in the network.
A Destination Up message MUST be acknowledged by the receiver issuing A Destination Up message MUST be sent by the modem to indicate that a
a Destination Up Response message (Section 9.10). When a Destination new destination has been detected. A Destination Up message MUST be
Up message is received and successfully processed, the receiver acknowledged by the router issuing a Destination Up Response message
should add knowledge of the new destination to its information base, (Section 10.10). When a Destination Up message is received and
indicating that the destination is accessible via the modem/router successfully processed, the router should add knowledge of the new
pair. destination to its information base, indicating that the destination
is accessible via the modem.
To construct a Destination Up message, the Message Type value in the 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 10.7) o MAC Address (Section 11.7)
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 10.12) o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 10.13) o Maximum Data Rate (Transmit) (Section 11.13)
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 10.16) o Latency (Section 11.16)
o Resources (Receive) (Section 10.17) The Destination Up message MAY contain one of each of the following
data items, if the data item is in use by the session:
o Resources (Transmit) (Section 10.18) o Resources (Receive) (Section 11.17)
o Relative Link Quality (Receive) (Section 10.19) o Resources (Transmit) (Section 11.18)
o Relative Link Quality (Transmit) (Section 10.20) o Relative Link Quality (Receive) (Section 11.19)
o Relative Link Quality (Transmit) (Section 11.20)
o Maximum Transmission Unit (MTU) (Section 11.21)
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 10.8) o IPv4 Address (Section 11.8)
o IPv6 Address (Section 10.9) o IPv6 Address (Section 11.9)
o IPv4 Attached Subnet (Section 10.10) o IPv4 Attached Subnet (Section 11.10)
o IPv6 Attached Subnet (Section 10.11) o IPv6 Attached Subnet (Section 11.11)
If the sender has IPv4 and/or IPv6 address information for a If the modem 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 router to probe for
for any address. any address.
9.10. Destination Up Response Message 10.10. Destination Up Response Message
A DLEP participant MUST send a Destination Up Response message to A DLEP router MUST send a Destination Up Response message to indicate
indicate whether a Destination Up message (Section 9.9) was whether a Destination Up message (Section 10.9) was successfully
successfully processed. 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 MAC Address
following data items: (Section 11.7) data item.
o MAC Address (Section 10.7) The Destination Up Response message MAY contain one Status
The Destination Up Response message MAY contain one of each of the (Section 11.1) data item.
A modem receiving a Destination Up Response message without a Status
data item MUST behave as if a Status data item with status code
'Success' had been received, see Table 3.
10.11. Destination Announce Message
If a router wishes to request information concerning a destination
that has not yet been announced by a mode via a Destination Up
message (Section 10.9), it MAY send a Destination Announce message to
the modem.
A Destination Announce message MUST be acknowledged by the modem
issuing a Destination Announce Response message (Section 10.12).
To construct a Destination Announce message, the Message Type value
in the message header is set to 17, from Table 1.
The Destination Announce message MUST contain one of each of the
following data items: following data items:
o Status (Section 10.1) o MAC Address (Section 11.7)
A receiver of a Destination Up Response message without a Status data The Destination Announce message MAY contain zero or more of the
item MUST behave as if a Status data item with status code 'Success' following data items, with different values:
had been received.
9.11. Destination Down Message o IPv4 Address (Section 11.8)
A DLEP peer MUST send a Destination Down message to report when a o IPv6 Address (Section 11.9)
destination (a remote node or a multicast group) is no longer
reachable. A Destination Down Response message (Section 9.12) MUST 10.12. Destination Announce Response Message
A DLEP modem MUST send a Destination Announce Response message to
indicate whether a Destination Announce message (Section 10.11) was
successfully processed and the destination identified by the MAC
Address data item is available.
When a Destination Announce Response message is received and
successfully processed, the router should add knowledge of the new
destination to its information base, indicating that the destination
is accessible via the modem.
To construct a Destination Announce Response message, the Message
Type value in the message header is set to 18, from Table 1.
The Destination Announce Response message MUST contain one of each of
the following data items:
o MAC Address (Section 11.7)
The Destination Announce Response message MAY contain one of each of
the following data items:
o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 11.13)
o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 11.16)
The Destination Announce Response message MAY contain one of each of
the following data items, if the data item is in use by the session:
o Resources (Receive) (Section 11.17)
o Resources (Transmit) (Section 11.18)
o Relative Link Quality (Receive) (Section 11.19)
o Relative Link Quality (Transmit) (Section 11.20)
o Maximum Transmission Unit (MTU) (Section 11.21)
The Destination Announce Response message MAY contain zero or more of
the following data items, with different values:
o IPv4 Address (Section 11.8)
o IPv6 Address (Section 11.9)
If the modem has IPv4 and/or IPv6 address information for a
destination it SHOULD include the relevant data items in the
Destination Announce Response message, reducing the need for the
router to probe for any address.
o Status (Section 11.1)
A router receiving a Destination Announce Response message without a
Status data item MUST behave as if a Status data item with status
code 'Success' had been received, see Table 3.
If a modem does not support Destination Announce messages, or the
modem is unable to report information immediately about the requested
information, if the destination is not currently accessible, for
example, the status code in the Status data item SHOULD be set to
'Request Denied'.
10.13. Destination Down Message
A DLEP participant MUST send a Destination Down message to report
when a destination (a remote node or a multicast group) is no longer
reachable. A Destination Down Response message (Section 10.14) 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.
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 10.7) o MAC Address (Section 11.7)
9.12. Destination Down Response Message It should be noted that both modem and router may send a Destination
Down message to its peer.
10.14. 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 9.11) indicate whether a received Destination Down message (Section 10.13)
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 10.7) o MAC Address (Section 11.7)
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 10.1) o Status (Section 11.1)
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, see Table 3.
9.13. Destination Update Message 10.15. Destination Update Message
A DLEP participant SHOULD send the Destination Update message when it A DLEP modem 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 10.7) o MAC Address (Section 11.7)
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 10.12) o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 10.13) o Maximum Data Rate (Transmit) (Section 11.13)
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 10.16) o Latency (Section 11.16)
The Destination Update message MAY contain one of each of the
following data items, if the data item is in use by the session:
o Resources (Receive) (Section 10.17) o Resources (Receive) (Section 11.17)
o Resources (Transmit) (Section 10.18) o Resources (Transmit) (Section 11.18)
o Relative Link Quality (Receive) (Section 10.19) o Relative Link Quality (Receive) (Section 11.19)
o Relative Link Quality (Transmit) (Section 10.20) o Relative Link Quality (Transmit) (Section 11.20)
o Maximum Transmission Unit (MTU) (Section 11.21)
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 10.8) o IPv4 Address (Section 11.8)
o IPv6 Address (Section 10.9)
9.14. Heartbeat Message o IPv6 Address (Section 11.9)
o IPv4 Attached Subnet (Section 11.10)
o IPv6 Attached Subnet (Section 11.11)
10.16. Heartbeat Message
While Heartbeat messages are not required by DLEP implementations, it While Heartbeat messages are not required by DLEP implementations, it
is strongly RECOMMENDED that Heartbeat messages be used. 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 9.3) or Session the Session Initialization message (Section 10.3) or Session
Initialization Response message (Section 9.4). Initialization Response message (Section 10.4).
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, turning off effectively sets the interval to an infinite value, turning off
Heartbeat messages. Great care MUST be taken when exercising this Heartbeat messages. Great care MUST be taken when exercising this
option. 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. peer (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 messages from the peer before initiating DLEP session termination
termination procedures. 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.
9.15. Link Characteristics Request Message 10.17. 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 a DLEP router
request that the modem initiate changes for specific characteristics to request that the modem initiate changes for specific
of the link. The request can reference either a real destination characteristics of the link. The request can reference either a real
(e.g., a remote node), or a logical destination (e.g., a multicast destination (e.g., a remote node), or a logical destination (e.g., a
group) within the network. multicast group) within the network.
The Link Characteristics Request message MAY contain either a Current The Link Characteristics Request message MAY contain either a Current
Data Rate (CDRR or CDRT) data item to request a different datarate Data Rate (CDRR or CDRT) data item to request a different datarate
than what is currently allocated, a Latency data item to request that than what is currently allocated, a Latency data item to request that
traffic delay on the link not exceed the specified value, or both. A traffic delay on the link not exceed the specified value, or both. A
Link Characteristics Response message (Section 9.16) is required to Link Characteristics Response message (Section 10.18) 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 router MAY use to
request metrics (via the Link Characteristics Response) from its request metrics (via the Link Characteristics Response) from its
partner. modem.
The sender of a Link Characteristics Request message should be aware The router sending a Link Characteristics Request message should be
that a request may take an extended period of time to complete. aware that a request may take an extended period of time to complete.
To construct a Link Characteristics Request message, the Message Type 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 10.7) o MAC Address (Section 11.7)
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 Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 11.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 10.16) o Latency (Section 11.16)
9.16. Link Characteristics Response Message 10.18. Link Characteristics Response Message
A DLEP participant MUST send a Link Characteristics Response message A DLEP modem MUST send a Link Characteristics Response message to
to indicate whether a received Link Characteristics Request message indicate whether a received Link Characteristics Request message
(Section 9.15) was successfully processed. The Link Characteristics (Section 10.17) 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 9.4)), if metrics were Initialization Response message (Section 10.4)), 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 the message MUST contain a Status
code 'Request Denied', see Table 3, MUST be added to the message. data item with status code 'Request Denied', see Table 3.
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 10.7) o MAC Address (Section 11.7)
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 10.12) o Maximum Data Rate (Receive) (Section 11.12)
o Maximum Data Rate (Transmit) (Section 10.13) o Maximum Data Rate (Transmit) (Section 11.13)
o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Receive) (Section 11.14)
o Latency (Section 10.16) o Current Data Rate (Transmit) (Section 11.15)
o Latency (Section 11.16)
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 10.17) o Status (Section 11.1)
o Resources (Transmit) (Section 10.18) The Link Characteristics Response message MAY contain one of each of
the following data items, if the data item is in use by the session:
o Relative Link Quality (Receive) (Section 10.19) o Resources (Receive) (Section 11.17)
o Relative Link Quality (Transmit) (Section 10.20) o Resources (Transmit) (Section 11.18)
o Status (Section 10.1) o Relative Link Quality (Receive) (Section 11.19)
A receiver of a Link Characteristics Response message without a o Relative Link Quality (Transmit) (Section 11.20)
o Maximum Transmission Unit (MTU) (Section 11.21)
A router receiving 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', see Table 3, had been received.
10. DLEP Data Items 11. 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 10.1) | | 1 | Status (Section 11.1) |
| 2 | IPv4 Connection Point (Section 10.2) | | 2 | IPv4 Connection Point (Section 11.2) |
| 3 | IPv6 Connection Point (Section 10.3) | | 3 | IPv6 Connection Point (Section 11.3) |
| 4 | Peer Type (Section 10.4) | | 4 | Peer Type (Section 11.4) |
| 5 | Heartbeat Interval (Section 10.5) | | 5 | Heartbeat Interval (Section 11.5) |
| 6 | Extensions Supported (Section 10.6) | | 6 | Extensions Supported (Section 11.6) |
| 7 | MAC Address (Section 10.7) | | 7 | MAC Address (Section 11.7) |
| 8 | IPv4 Address (Section 10.8) | | 8 | IPv4 Address (Section 11.8) |
| 9 | IPv6 Address (Section 10.9) | | 9 | IPv6 Address (Section 11.9) |
| 10 | IPv4 Attached Subnet (Section 10.10) | | 10 | IPv4 Attached Subnet (Section 11.10) |
| 11 | IPv6 Attached Subnet (Section 10.11) | | 11 | IPv6 Attached Subnet (Section 11.11) |
| 12 | Maximum Data Rate (Receive) MDRR) (Section 10.12) | | 12 | Maximum Data Rate (Receive) MDRR) (Section 11.12) |
| 13 | Maximum Data Rate (Transmit) (MDRT) (Section 10.13) | | 13 | Maximum Data Rate (Transmit) (MDRT) (Section 11.13) |
| 14 | Current Data Rate (Receive) (CDRR) (Section 10.14) | | 14 | Current Data Rate (Receive) (CDRR) (Section 11.14) |
| 15 | Current Data Rate (Transmit) (CDRT) (Section 10.15) | | 15 | Current Data Rate (Transmit) (CDRT) (Section 11.15) |
| 16 | Latency (Section 10.16) | | 16 | Latency (Section 11.16) |
| 17 | Resources (Receive) (RESR) (Section 10.17) | | 17 | Resources (Receive) (RESR) (Section 11.17) |
| 18 | Resources (Transmit) (REST) (Section 10.18) | | 18 | Resources (Transmit) (REST) (Section 11.18) |
| 19 | Relative Link Quality (Receive) (RLQR) (Section | | 19 | Relative Link Quality (Receive) (RLQR) (Section |
| | 10.19) | | | 11.19) |
| 20 | Relative Link Quality (Transmit) (RLQT) (Section | | 20 | Relative Link Quality (Transmit) (RLQT) (Section |
| | 10.20) | | | 11.20) |
| 21-65407 | Reserved for future extensions | | 21 | Maximum Transmission Unit (MTU) (Section 11.21) |
| 22-65407 | 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
10.1. Status 11.1. Status
The Status data item MAY appear in the Session Initialization The Status data item MAY appear in the Session Initialization
Response (Section 9.4), Session Termination (Section 9.7), Session Response (Section 10.4), Session Termination (Section 10.7), Session
Termination Response (Section 9.8), Session Update Response Termination Response (Section 10.8), Session Update Response
(Section 9.6), Destination Up Response (Section 9.10), Destination (Section 10.6), Destination Up Response (Section 10.10), Destination
Down Response (Section 9.12) and Link Characteristics Response Down Response (Section 10.14) and Link Characteristics Response
(Section 9.16) messages. (Section 10.18) messages.
For the Session Termination message (Section 9.7), the Status data For the Session Termination message (Section 10.7), 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 36, line 18 skipping to change at page 39, 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 9.3) in the | | | | | message (Section 10.3) 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 |
| | | | 9.16). | | | | | 10.18). |
| Timed Out | 5 | Terminate | The session has timed out. | | Timed Out | 5 | Terminate | The session has timed out. |
| <Reserved> | 6-90 | Terminate | Reserved for future | | <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 |
| | | | 9.10) to indicate no further | | | | | 10.10) 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. |
| <Reserved> | 102-243 | Continue | Reserved for future | | <Reserved> | 102-243 | 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 immediately instead of sending any relevant response
failure mode of 'Continue' indicates that the session SHOULD continue message, by sending a Session Termination message (Section 10.7)
as normal. containing the status code, and then transitioning to the Session
Termination state.
10.2. IPv4 Connection Point A failure mode of 'Continue' indicates that the session SHOULD
continue as normal.
11.2. 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 9.2). signal (Section 10.2).
The IPv4 Connection Point data item indicates the IPv4 address and, The IPv4 Connection Point data item indicates the IPv4 address and,
optionally, the TCP port number on the DLEP modem available for optionally, the TCP port number on the DLEP modem available for
connections. If provided, the receiver MUST use this information to connections. If provided, the router MUST use this information to
perform the TCP connect to the DLEP server. perform the TCP connect to the modem.
The IPv4 Connection Point data item contains the following fields: The IPv4 Connection Point data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | IPv4 Address... : | Flags | IPv4 Address... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 37, line 44 skipping to change at page 40, line 48
Length: 5 (or 7 if TCP Port included) Length: 5 (or 7 if TCP Port included)
Flags: Flags field, defined below. Flags: Flags field, defined below.
IPv4 Address: The IPv4 address listening on the DLEP modem. IPv4 Address: The IPv4 address listening on the 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 router MUST use the DLEP well-known port
number (Section 12.7) to establish the TCP connection. number (Section 13.6) to establish the TCP connection.
The Flags field is defined as: The Flags field is defined as:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| MBZ |T| | Reserved |T|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
T: Use TLS flag, indicating whether the TCP connection requires the T: Use TLS flag, indicating whether the TCP connection requires the
use of TLS (1), or not (0). use of TLS (1), or not (0).
MBZ: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.3. IPv6 Connection Point 11.3. 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 9.2). signal (Section 10.2).
The IPv6 Connection Point data item indicates the IPv6 address and, The IPv6 Connection Point data item indicates the IPv6 address and,
optionally, the TCP port number on the DLEP modem available for optionally, the TCP port number on the DLEP modem available for
connections. If provided, the receiver MUST use this information to connections. If provided, the router MUST use this information to
perform the TCP connect to the DLEP server. perform the TCP connect to the modem.
The IPv6 Connection Point data item contains the following fields: The IPv6 Connection Point data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | IPv6 Address : | Flags | IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 38, line 49 skipping to change at page 42, line 7
Length: 17 (or 19 if TCP Port included) Length: 17 (or 19 if TCP Port included)
Flags: Flags field, defined below. Flags: Flags field, defined below.
IPv6 Address: The IPv6 address listening on the DLEP modem. IPv6 Address: The IPv6 address listening on the 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 router MUST use the DLEP well-known port
port number (Section 12.7) to establish the TCP connection. number (Section 13.6) to establish the TCP connection.
The Flags field is defined as: The Flags field is defined as:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| MBZ |T| | Reserved |T|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
T: Use TLS flag, indicating whether the TCP connection requires the T: Use TLS flag, indicating whether the TCP connection requires the
use of TLS (1), or not (0). use of TLS (1), or not (0).
MBZ: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.4. Peer Type 11.4. 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 9.1) and Peer Offer (Section 9.2) signals, and the Session (Section 10.1) and Peer Offer (Section 10.2) signals, and the Session
Initialization (Section 9.3) and Session Initialization Response Initialization (Section 10.3) and Session Initialization Response
(Section 9.4) messages. (Section 10.4) messages.
The Peer Type data item is used by the router and modem to give The Peer Type data item is used by the router and modem to give
additional information as to its type. The peer type is a string and additional information as to its type. The peer type is a string and
is envisioned to be used for informational purposes (e.g., as output is envisioned to be used for informational purposes (e.g., as output
in a display command). in a display command).
The Peer Type data item contains the following fields: The Peer Type data item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
skipping to change at page 40, line 5 skipping to change at page 43, line 10
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 implementations 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.
10.5. Heartbeat Interval 11.5. 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 9.3) and Session Initialization Response Initialization (Section 10.3) and Session Initialization Response
(Section 9.4) messages to indicate the Heartbeat timeout window to be (Section 10.4) messages to indicate the Heartbeat timeout window to
used by the sender. be 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 9.14). By specifying an Interval value of 0, messages (Section 10.16). 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 40, line 35 skipping to change at page 43, line 40
| 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.
10.6. Extensions Supported 11.6. 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 9.3) and Session Initialization Response Initialization (Section 10.3) and Session Initialization Response
(Section 9.4) messages. (Section 10.4) messages.
The Extensions Supported data item is used by the router and modem to The Extensions Supported data item is used by the router and modem to
negotiate additional optional functionality they are willing to negotiate additional optional functionality they are willing to
support. The Extensions List is a concatenation of the types of each support. The Extensions List is a concatenation of the types of each
supported extension, found in the IANA DLEP Extensions repository. supported extension, found in the IANA DLEP Extensions repository.
Each Extension Type definition includes which additional signals and Each Extension Type definition includes which additional signals and
data-items are supported. data-items are supported.
The Extensions Supported data item contains the following fields: The Extensions Supported data item contains the following fields:
skipping to change at page 41, line 21 skipping to change at page 44, line 23
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
10.7. MAC Address 11.7. 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 9.9), Destination Up Response messages (i.e., Destination Up (Section 10.9), Destination Up
(Section 9.10), Destination Down (Section 9.11), Destination Down Response (Section 10.10), Destination Down (Section 10.13),
Response (Section 9.12), Destination Update (Section 9.13), Link Destination Down Response (Section 10.14), Destination Update
Characteristics Request (Section 9.15), and Link Characteristics (Section 10.15), Link Characteristics Request (Section 10.17), and
Response (Section 9.16)). Link Characteristics Response (Section 10.18)).
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 41, line 51 skipping to change at page 45, line 4
| MAC Address : | MAC Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: MAC Address : : MAC Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: 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.
10.8. IPv4 Address 11.8. 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 9.5), Destination Up (Section 9.9) and Destination Update (Section 10.5), Destination Up (Section 10.9) and Destination Update
(Section 9.13) messages. (Section 10.15) messages.
When included in Destination messages, this data item contains the When included in Destination messages, this data item contains the
IPv4 address of the destination. When included in the Session Update IPv4 address of the destination. When included in the Session Update
message, this data item contains the IPv4 address of the peer. In message, this data item contains the IPv4 address of the peer. In
either case, the data item also contains an indication of whether either case, the data item also contains an indication of whether
this is a new or existing address, or is a deletion of a previously this is a new or existing address, or is a deletion of a previously
known address. known address.
The IPv4 Address data item contains the following fields: The IPv4 Address data item contains the following fields:
skipping to change at page 42, line 42 skipping to change at page 45, line 43
Length: 5 Length: 5
Flags: Flags field, defined below. Flags: Flags field, defined below.
IPv4 Address: The IPv4 address of the destination or peer. IPv4 Address: The IPv4 address of the destination or peer.
The Flags field is defined as: The Flags field is defined as:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| MBZ |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing A: Add/Drop flag, indicating whether this is a new or existing
address (1), or a withdrawal of an address (0). address (1), or a withdrawal of an address (0).
MBZ: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.9. IPv6 Address 11.9. 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 9.5), Destination Up (Section 9.9) and Destination Update (Section 10.5), Destination Up (Section 10.9) and Destination Update
(Section 9.13) messages. When included in Destination messages, this (Section 10.15) messages. When included in Destination messages,
data item contains the IPv6 address of the destination. When this 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 43, line 46 skipping to change at page 46, line 46
Length: 17 Length: 17
Flags: Flags field, defined below. Flags: Flags field, defined below.
IPv6 Address: IPv6 Address of the destination or peer. IPv6 Address: IPv6 Address of the destination or peer.
The Flags field is defined as: The Flags field is defined as:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| MBZ |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing A: Add/Drop flag, indicating whether this is a new or existing
address (1), or a withdrawal of an address (0). address (1), or a withdrawal of an address (0).
MBZ: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.10. IPv4 Attached Subnet 11.10. IPv4 Attached Subnet
The DLEP IPv4 Attached Subnet allows a device to declare that it has The DLEP IPv4 Attached Subnet allows a device to declare that it has
an IPv4 subnet (e.g., a stub network) attached, that it has become an IPv4 subnet (e.g., a stub network) attached, that it has become
aware of an IPv4 subnet being present at a remote destination, or aware of an IPv4 subnet being present at a remote destination, or
that it has become aware of the loss of a subnet at the remote that it has become aware of the loss of a subnet at the remote
destination. The IPv4 Attached Subnet data item MAY appear in the destination. The IPv4 Attached Subnet data item MAY appear in the
Destination Up (Section 9.9) message. Destination Up (Section 10.9) and Destination Update (Section 10.15)
messages.
The DLEP IPv4 Attached Subnet data item contains the following The DLEP IPv4 Attached Subnet data item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | IPv4 Attached Subnet : | Flags | IPv4 Attached Subnet :
skipping to change at page 44, line 43 skipping to change at page 47, line 44
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 specified range MUST be considered as prefix length outside the specified range MUST be considered as
invalid. invalid.
The Flags field is defined as: The Flags field is defined as:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| MBZ |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing subnet A: Add/Drop flag, indicating whether this is a new or existing subnet
address (1), or a withdrawal of a subnet address (0). address (1), or a withdrawal of a subnet address (0).
MBZ: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.11. IPv6 Attached Subnet 11.11. 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 9.9) message. As in the case of the IPv4 attached Subnet (Section 10.9) and Destination Update (Section 10.15) messages.
data item above, once an IPv6 attached subnet has been declared, it
SHALL NOT be withdrawn without withdrawing the destination (via the
Destination Down message (Section 9.11)) and re-issuing the
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | IPv6 Attached Subnet : | Flags | IPv6 Attached Subnet :
skipping to change at page 46, line 7 skipping to change at page 48, line 48
IPv6 Attached Subnet: The IPv6 subnet reachable at the destination. 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.
The Flags field is defined as: The Flags field is defined as:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| MBZ |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
A: Add/Drop flag, indicating whether this is a new or existing subnet A: Add/Drop flag, indicating whether this is a new or existing subnet
address (1), or a withdrawal of a subnet address (0). address (1), or a withdrawal of a subnet address (0).
MBZ: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.12. Maximum Data Rate (Receive) 11.12. 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 9.4), and MAY appear Session Initialization Response message (Section 10.4), and MAY
in the Session Update (Section 9.5), Destination Up (Section 9.9), appear in the Session Update (Section 10.5), Destination Up
Destination Update (Section 9.13) and Link Characteristics Response (Section 10.9), Destination Update (Section 10.15) and Link
(Section 9.16) messages to indicate the maximum theoretical data Characteristics Response (Section 10.18) messages to indicate the
rate, in bits per second, that can be achieved while receiving data maximum theoretical data rate, in bits per second, that can be
on the link. achieved while receiving data on the link.
The Maximum Data Rate (Receive) data item contains the following The Maximum Data Rate (Receive) data item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MDRR (bps) : | MDRR (bps) :
skipping to change at page 46, line 46 skipping to change at page 49, line 38
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
10.13. Maximum Data Rate (Transmit) 11.13. 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 9.4), and MAY appear Session Initialization Response message (Section 10.4), and MAY
in the Session Update (Section 9.5), Destination Up (Section 9.9), appear in the Session Update (Section 10.5), Destination Up
Destination Update (Section 9.13) and Link Characteristics Response (Section 10.9), Destination Update (Section 10.15) and Link
(Section 9.16) messages to indicate the maximum theoretical data Characteristics Response (Section 10.18) messages to indicate the
rate, in bits per second, that can be achieved while transmitting maximum theoretical data rate, in bits per second, that can be
data on the link. achieved while transmitting data on the link.
The Maximum Data Rate (Transmit) data item contains the following The Maximum Data Rate (Transmit) data item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MDRT (bps) : | MDRT (bps) :
skipping to change at page 47, line 28 skipping to change at page 50, line 23
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
10.14. Current Data Rate (Receive) 11.14. 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 9.4), and MAY appear Session Initialization Response message (Section 10.4), and MAY
in the Session Update (Section 9.5), Destination Up (Section 9.9), appear in the Session Update (Section 10.5), Destination Up
Destination Update (Section 9.13) and Link Characteristics Response (Section 10.9), Destination Update (Section 10.15) and Link
(Section 9.16) messages to indicate the rate at which the link is Characteristics Response (Section 10.18) messages to indicate the
currently operating for receiving traffic. rate at which the link is currently operating for receiving traffic.
When used in the Link Characteristics Request message (Section 9.15), When used in the Link Characteristics Request message
CDRR represents the desired receive rate, in bits per second, on the (Section 10.17), CDRR represents the desired receive rate, in bits
link. per second, on the link.
The Current Data Rate (Receive) data item contains the following The Current Data Rate (Receive) data item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRR (bps) : | CDRR (bps) :
skipping to change at page 48, line 18 skipping to change at page 51, line 4
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRR (bps) : | CDRR (bps) :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: CDRR (bps) | : CDRR (bps) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 14 Data Item Type: 14
Length: 8 Length: 8
Current Data Rate (Receive): A 64-bit unsigned integer, representing Current Data Rate (Receive): A 64-bit unsigned integer, representing
the current data rate, in bits per second, that can currently be the current data rate, in bits per second, that can currently be
achieved while receiving traffic on the link. achieved while receiving traffic on the link.
If there is no distinction between current and maximum receive data If there is no distinction between current and maximum receive data
rates, current data rate receive MUST be set equal to the maximum rates, current data rate receive MUST be set equal to the maximum
data rate receive. data rate receive.
10.15. Current Data Rate (Transmit) 11.15. 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 9.4), and MAY appear Session Initialization Response message (Section 10.4), and MAY
in the Session Update (Section 9.5), Destination Up (Section 9.9), appear in the Session Update (Section 10.5), Destination Up
Destination Update (Section 9.13), and Link Characteristics Response (Section 10.9), Destination Update (Section 10.15), and Link
(Section 9.16) messages to indicate the rate at which the link is Characteristics Response (Section 10.18) messages to indicate the
currently operating for transmitting traffic. rate at which the link is currently operating for transmitting
traffic.
When used in the Link Characteristics Request message (Section 9.15), When used in the Link Characteristics Request message
CDRT represents the desired transmit rate, in bits per second, on the (Section 10.17), CDRT represents the desired transmit rate, in bits
link. per second, on the link.
The Current Data Rate (Transmit) data item contains the following The Current Data Rate (Transmit) data item contains the following
fields: fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CDRT (bps) : | CDRT (bps) :
skipping to change at page 49, line 16 skipping to change at page 52, line 5
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.
10.16. Latency 11.16. Latency
The Latency data item MUST appear in the Session Initialization The Latency data item MUST appear in the Session Initialization
Response message (Section 9.4), and MAY appear in the Session Update Response message (Section 10.4), and MAY appear in the Session Update
(Section 9.5), Destination Up (Section 9.9), Destination Update (Section 10.5), Destination Up (Section 10.9), Destination Update
(Section 9.13), and Link Characteristics Response (Section 9.16) (Section 10.15), and Link Characteristics Response (Section 10.18)
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 9.15), When used in the Link Characteristics Request message
Latency represents the maximum latency desired on the link. (Section 10.17), 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 50, line 5 skipping to change at page 52, line 40
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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.
10.17. Resources (Receive) 11.17. 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 9.4), Session Update Initialization Response message (Section 10.4), Session Update
(Section 9.5), Destination Up (Section 9.9), Destination Update (Section 10.5), Destination Up (Section 10.9), Destination Update
(Section 9.13) and Link Characteristics Response (Section 9.16) (Section 10.15) and Link Characteristics Response (Section 10.18)
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 50, line 38 skipping to change at page 53, line 24
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.
10.18. Resources (Transmit) 11.18. 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 9.4), Session Update Initialization Response message (Section 10.4), Session Update
(Section 9.5), Destination Up (Section 9.9), Destination Update (Section 10.5), Destination Up (Section 10.9), Destination Update
(Section 9.13) and Link Characteristics Response (Section 9.16) (Section 10.15) and Link Characteristics Response (Section 10.18)
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 51, line 24 skipping to change at page 54, line 8
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.
10.19. Relative Link Quality (Receive) 11.19. 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 9.4), Session the Session Initialization Response message (Section 10.4), Session
Update (Section 9.5), Destination Up (Section 9.9), Destination Update (Section 10.5), Destination Up (Section 10.9), Destination
Update (Section 9.13) and Link Characteristics Response Update (Section 10.15) and Link Characteristics Response
(Section 9.16) messages to indicate the quality of the link for (Section 10.18) 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 52, line 8 skipping to change at page 54, line 40
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.
10.20. Relative Link Quality (Transmit) 11.20. 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 9.4), Session the Session Initialization Response message (Section 10.4), Session
Update (Section 9.5), Destination Up (Section 9.9), Destination Update (Section 10.5), Destination Up (Section 10.9), Destination
Update (Section 9.13) and Link Characteristics Response Update (Section 10.15) and Link Characteristics Response
(Section 9.16) messages to indicate the quality of the link for (Section 10.18) 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 52, line 40 skipping to change at page 55, line 25
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.
11. Security Considerations 11.21. Maximum Transmission Unit (MTU)
The Maximum Transmission Unit (MTU) data item MAY appear in the
Session Initialization Response message (Section 10.4), Session
Update (Section 10.5), Destination Up (Section 10.9), Destination
Update (Section 10.15) and Link Characteristics Response
(Section 10.18) messages to indicate the maximum size, in octets, of
an IP packet that can be transmitted without fragmentation, including
headers, but excluding any lower layer headers.
The Maximum Transmission Unit (MTU) data item contains the following
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 21
Length: 2
Maximum Transmission Unit (MTU): The maximum size, in octets, of an
IP packet that can be transmitted without fragmentation, including
headers, but excluding any lower layer headers.
If a device cannot calculate the MTU, this data item SHOULD NOT be
issued.
12. 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. An attacker might pretend to be a DLEP peer, either at DLEP
session initialization, or by injection of messages once a session initialization, or by injection of 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 implementation to inappropriately alter its information
concerning network status. base concerning network status.
If the modem and router are separated by more than a single hop, Since DLEP is restricted to operation over a single (possibly
session messages could be altered in order to subvert the behaviour logical) hop at layer 2, implementations requiring authentication
of either or both DLEP participants. Under these circumstances, DLEP and/or encryption of traffic MUST take steps to secure the Layer 2
participants MUST implement TLS [RFC5246]. link.
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 hosts that persistently fail Session
Initialization having provided an acceptable Discovery signal, and Initialization having provided an acceptable Discovery signal, and
ignore Peer Discovery signals from such peers. ignore Peer Discovery signals from such hosts.
This specification does not address security of the data plane, as it This specification does not address security of the data plane, as it
(the data plane) is not affected, and standard security procedures (the data plane) is not affected, and standard security procedures
can be employed. can be employed.
12. IANA Considerations 13. IANA Considerations
This section specifies requests to IANA. This section specifies requests to IANA.
12.1. Registrations 13.1. Registrations
This specification defines: This specification defines:
o A new repository for DLEP signals and messages, with sixteen (16) o A new repository for DLEP signals and messages, with eighteen (18)
values currently assigned. values currently assigned.
o Reservation of a Private Use numbering space for experimental DLEP o Reservation of a Private Use numbering space within the above
signals and messages. repository for experimental DLEP signals and messages.
o A new repository for DLEP data items, with twenty-four (24) values o A new repository for DLEP data items, with twenty-one (21) values
currently assigned. currently assigned.
o Reservation of a Private Use numbering space in the data items o Reservation of a Private Use numbering space within the data items
repository for experimental data items. repository for experimental data items.
o A new repository for DLEP status codes, with eight (8) currently o A new repository for DLEP status codes, with eight (8) currently
assigned. assigned.
o Reservation of a Private Use numbering space in the status codes o Reservation of a Private Use numbering space within the status
repository for experimental status codes. codes repository for experimental status codes.
o A new repository for DLEP extensions, with one (1) value currently o A new repository for DLEP extensions, with one (1) value currently
assigned. assigned.
o Reservation of a Private Use numbering space in the extension o Reservation of a Private Use numbering space within the extension
repository for experimental extensions. repository for experimental extensions.
o A request for allocation of a well-known port for DLEP TCP and UDP o A request for allocation of a well-known port for DLEP TCP and UDP
communication. communication.
o A request for allocation of a multicast IP address for DLEP o A request for allocation of a link-local multicast IPv4 address
discovery. for DLEP discovery.
12.2. Expert Review: Evaluation Guidelines
No additional guidelines for expert review are anticipated. o A request for allocation of a link-local multicast IPv6 address
for DLEP discovery.
12.3. Signal/Message Type Registration 13.2. Signal/Message Type Registration
A new repository must be created with the values of the DLEP signals A new repository must be created with the values of the DLEP signals
and messages. and messages, entitled "Message Type Values for the Dynamic Link
Event Protocol (DLEP)". The repository is to be managed using the
"Specification Required" policy documented in [RFC5226].
All signal and message values are in the range [0..65535], defined in All signal and message values are in the range [0..65535], defined in
Table 1. Table 1.
12.4. DLEP Data Item Registrations 13.3. DLEP Data Item Registrations
A new repository for DLEP data items must be created. A new repository for DLEP data items must be created, entitled "Data
Item Type Values for the Dynamic Link Event Protocol (DLEP)". The
repository is to be managed using the "Specification Required" policy
documented in [RFC5226].
All data item values are in the range [0..65535], defined in Table 2. All data item values are in the range [0..65535], defined in Table 2.
12.5. DLEP Status Code Registrations 13.4. DLEP Status Code Registrations
A new repository for DLEP status codes must be created. A new repository for DLEP status codes must be created, entitled
"Status Code Values for the Dynamic Link Event Protocol (DLEP)". The
repository is to be managed using the "Specification Required" policy
documented in [RFC5226].
All status codes are in the range [0..255], defined in Table 3. All status codes are in the range [0..255], defined in Table 3.
12.6. DLEP Extensions Registrations 13.5. DLEP Extensions Registrations
A new repository for DLEP extensions must be created. A new repository for DLEP extensions must be created, entitled
"Extension Type Values for the Dynamic Link Event Protocol (DLEP)".
The repository is to be managed using the "Specification Required"
policy documented in [RFC5226].
All extension values are in the range [0..65535]. Current All extension values are in the range [0..65535]. Current
allocations are: allocations are:
+-------------+-----------------------------------------------------+ +-------------+-----------------------------------------------------+
| Code | Description | | Code | Description |
+-------------+-----------------------------------------------------+ +-------------+-----------------------------------------------------+
| 0 | Reserved | | 0 | Reserved |
| 1 | Credit Windowing | | 1 | Credit Windowing |
| 2-65519 | Reserved for future extensions | | 2-65519 | Unassigned. Available for future extensions |
| 65520-65534 | Private Use. Available for experiments | | 65520-65534 | Private Use. Available for experiments |
| 65535 | Reserved | | 65535 | Reserved |
+-------------+-----------------------------------------------------+ +-------------+-----------------------------------------------------+
Table 4: DLEP Extension types Table 4: DLEP Extension types
12.7. DLEP Well-known Port 13.6. DLEP Well-known Port
It is requested that IANA allocate a single well-known port number It is requested that IANA allocate a single well-known port number
for both TCP and UDP, for DLEP communication. SCTP port allocation for both TCP and UDP, for DLEP communication. SCTP port allocation
is not required. is not required.
12.8. DLEP IPv6 Link-local Multicast Address 13.7. DLEP IPv4 Link-local Multicast Address
It is requested that IANA allocate an IPv4 link-local multicast
address for DLEP discovery signals.
13.8. DLEP IPv6 Link-local Multicast Address
It is requested that IANA allocate an IPv6 link-local multicast It is requested that IANA allocate an IPv6 link-local multicast
address for DLEP discovery signals. address for DLEP discovery signals.
13. Acknowledgements 14. 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, Lou Berger, and Victoria Mercieca.
14. References 15. References
14.1. Normative References 15.1. Normative References
[CREDIT] Ratliff, S., "Credit Windowing extension for DLEP", draft- [CREDIT] Ratliff, S., "Credit Windowing extension for DLEP", draft-
ietf-manet-credit-window-00 IETF draft, October 2015. 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,
RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
14.2. Informative References 15.2. Informative References
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
(TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/ IANA Considerations Section in RFCs", BCP 26, RFC 5226,
RFC5246, August 2008, DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5246>. <http://www.rfc-editor.org/info/rfc5226>.
[RFC5578] Berry, B., Ed., Ratliff, S., Paradise, E., Kaiser, T., and [RFC5578] Berry, B., Ed., Ratliff, S., Paradise, E., Kaiser, T., and
M. Adams, "PPP over Ethernet (PPPoE) Extensions for Credit M. Adams, "PPP over Ethernet (PPPoE) Extensions for Credit
Flow and Link Metrics", RFC 5578, DOI 10.17487/RFC5578, Flow and Link Metrics", RFC 5578, DOI 10.17487/RFC5578,
February 2010, <http://www.rfc-editor.org/info/rfc5578>. February 2010, <http://www.rfc-editor.org/info/rfc5578>.
Appendix A. Discovery Signal Flows Appendix A. Discovery Signal Flows
Router Modem Signal Description Router Modem Signal Description
======================================================================== ========================================================================
| Router initiates discovery, starts | Router initiates discovery, starts
| a timer, send Peer Discovery | a timer, send Peer Discovery
|-------Peer Discovery---->|| signal. |-------Peer Discovery---->|| signal.
~ ~ ~ ~ ~ ~ ~ Router discovery timer expires ~ ~ ~ ~ ~ ~ ~ Router discovery timer expires
without receiving Peer Offer. without receiving Peer Offer.
skipping to change at page 56, line 34 skipping to change at page 60, line 31
|<--------Peer Offer-------------| Connection Point information. |<--------Peer Offer-------------| Connection Point information.
: :
: Router MAY cancel discovery timer : Router MAY cancel discovery timer
: and stop sending Peer Discovery : and stop sending Peer Discovery
: signals. : signals.
Appendix B. Peer Level Message Flows Appendix B. Peer Level Message Flows
B.1. Session Initialization B.1. Session Initialization
Router Modem Signal Description Router Modem Message Description
======================================================================== ========================================================================
| Router connects to discovered or | Router connects to discovered or
| pre-configured Modem Connection | pre-configured Modem Connection
|---------TCP connect----------> Point. |---------TCP connect----------> Point.
| |
| Router sends Session Initialization | Router sends Session
|----Session Initialization----->| message. |----Session Initialization----->| Initialization message.
| |
| Modem receives Session Initialization | Modem receives Session
| message. | Initialization message.
| |
| Modem sends Session Initialization | Modem sends Session Initialization
|<--Session Initialization Resp.-| Response, with Success status data item. |<--Session Initialization Resp.-| Response, with Success status data
| | item.
| | | |
|<<============================>>| Session established. Heartbeats |<<============================>>| Session established. Heartbeats
: : begin. : : begin.
B.2. Session Initialization - Refused B.2. Session Initialization - Refused
Router Modem Signal Description Router Modem Message Description
======================================================================== ========================================================================
| Router connects to discovered or | Router connects to discovered or
| pre-configured Modem Connection | pre-configured Modem Connection
|---------TCP connect----------> Point. |---------TCP connect----------> Point.
| |
| Router sends Session Initialization | Router sends Session
|-----Session Initialization---->| message. |-----Session Initialization---->| Initialization message.
| |
| Modem receives Session Initialization | Modem receives Session
| message, and will not support the | Initialization message, and will
| advertised extensions. | not support the advertised
| extensions.
| |
| Modem sends Session Initialization | Modem sends Session Initialization
| Response, with 'Request Denied' status | Response, with 'Request Denied'
|<-Session Initialization Resp.--| data item. |<-Session Initialization Resp.--| status data item.
| |
| |
| Router receives negative Session | Router receives negative Session
| Initialization Response, closes | Initialization Response, closes
||---------TCP close------------|| TCP connection. ||---------TCP close------------|| TCP connection.
B.3. Router Changes IP Addresses B.3. Router Changes IP Addresses
Router Modem Signal Description Router Modem Message Description
======================================================================== ========================================================================
| Router sends Session Update message to | Router sends Session Update
|-------Session Update---------->| announce change of IP address |-------Session Update---------->| message to announce change of IP
| address
| |
| Modem receives Session Update message | Modem receives Session Update
| and updates internal state. | message and updates internal
| state.
| |
|<----Session Update Response----| Modem sends Session Update Response. |<----Session Update Response----| Modem sends Session Update
| Response.
B.4. Modem Changes Session-wide Metrics B.4. Modem Changes Session-wide Metrics
Router Modem Signal Description Router Modem Message Description
======================================================================== ========================================================================
| Modem sends Session Update message to | Modem sends Session Update message
| announce change of modem-wide | to announce change of modem-wide
|<--------Session Update---------| metrics |<--------Session Update---------| metrics
| |
| Router receives Session Update message | Router receives Session Update
| and updates internal state. | message and updates internal
| state.
| |
|----Session Update Response---->| Router sends Session Update Response. |----Session Update Response---->| Router sends Session Update
| Response.
B.5. Router Terminates Session B.5. Router Terminates Session
Router Modem Signal Description Router Modem Message Description
======================================================================== ========================================================================
| Router sends Session Termination | Router sends Session Termination
|------Session Termination------>| message with Status data item. |------Session Termination------>| message with Status data item.
| | | |
|-------TCP shutdown (send)---> | Router stops sending messages. |-------TCP shutdown (send)---> | Router stops sending messages.
| |
| Modem receives Session Termination, | Modem receives Session
| stops counting received heartbeats | Termination, stops counting
| and stops sending heartbeats. | received heartbeats and stops
| sending heartbeats.
| |
| Modem sends Session Termination Response | Modem sends Session Termination
|<---Session Termination Resp.---| with Status 'Success'. |<---Session Termination Resp.---| Response with Status 'Success'.
| |
| Modem stops sending messages. | Modem stops sending messages.
| |
||---------TCP close------------|| Session terminated. ||---------TCP close------------|| Session terminated.
B.6. Modem Terminates Session B.6. Modem Terminates Session
Router Modem Signal Description Router Modem Message Description
======================================================================== ========================================================================
| Modem sends Session Termination | Modem sends Session Termination
|<----Session Termination--------| message with Status data item. |<----Session Termination--------| message with Status data item.
| |
| Modem stops sending messages. | Modem stops sending messages.
| |
| Router receives Session Termination, | Router receives Session
| stops counting received heartbeats | Termination, stops counting
| and stops sending heartbeats. | received heartbeats and stops
| sending heartbeats.
| |
| Router sends Session Termination Response | Router sends Session Termination
|---Session Termination Resp.--->| with Status 'Success'. |---Session Termination Resp.--->| Response with Status 'Success'.
| |
| Router stops sending messages. | Router stops sending messages.
| |
||---------TCP close------------|| Session terminated. ||---------TCP close------------|| Session terminated.
B.7. Session Heartbeats B.7. Session Heartbeats
Router Modem Signal Description Router Modem Message Description
======================================================================== ========================================================================
|----------Heartbeat------------>| Router sends heartbeat message |----------Heartbeat------------>| Router sends heartbeat message
| |
| Modem resets heartbeats missed | Modem resets heartbeats missed
| counter. | counter.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|---------[Any message]--------->| When the Modem receives any message |---------[Any message]--------->| When the Modem receives any
| from the Router. | message from the Router.
| |
| Modem resets heartbeats missed | Modem resets heartbeats missed
| counter. | counter.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|<---------Heartbeat-------------| Modem sends heartbeat message |<---------Heartbeat-------------| Modem sends heartbeat message
| |
| Router resets heartbeats missed | Router resets heartbeats missed
| counter. | counter.
skipping to change at page 60, line 37 skipping to change at page 64, line 37
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|<--------[Any message]----------| When the Router receives any |<--------[Any message]----------| When the Router receives any
| message from the Modem. | message from the Modem.
| |
| Modem resets heartbeats missed | Modem resets heartbeats missed
| counter. | counter.
B.8. Router Detects a Heartbeat timeout B.8. Router Detects a Heartbeat timeout
Router Modem Signal Description Router Modem Message Description
======================================================================== ========================================================================
||<----------------------| Router misses a heartbeat ||<----------------------| Router misses a heartbeat
| ||<----------------------| Router misses too many heartbeats | ||<----------------------| Router misses too many heartbeats
| |
| |
|------Session Termination------>| Router sends Session Termination |------Session Termination------>| Router sends Session Termination
| message with 'Timeout' Status | message with 'Timeout' Status
| data item. | data item.
: :
: Termination proceeds as above. : Termination proceeds as above.
B.9. Modem Detects a Heartbeat timeout B.9. Modem Detects a Heartbeat timeout
Router Modem Signal Description Router Modem Message Description
======================================================================== ========================================================================
|---------------------->|| Modem misses a heartbeat |---------------------->|| Modem misses a heartbeat
|---------------------->|| | Modem misses too many heartbeats |---------------------->|| | Modem misses too many heartbeats
| |
| |
|<-----Session Termination-------| Modem sends Session Termination |<-----Session Termination-------| Modem sends Session Termination
| message with 'Timeout' Status | message with 'Timeout' Status
| data item. | data item.
: :
: Termination proceeds as above. : Termination proceeds as above.
Appendix C. Destination Specific Signal Flows Appendix C. Destination Specific Message Flows
C.1. Common Destination Signaling
Router Modem Signal Description C.1. Common Destination Notification
Router Modem Message Description
======================================================================== ========================================================================
| Modem detects a new logical | Modem detects a new logical
| destination is reachable, and | destination is reachable, and
|<-------Destination Up----------| sends Destination Up message. |<-------Destination Up----------| sends Destination Up message.
| |
|------Destination Up Resp.----->| Router sends Destination Up Response. |------Destination Up Resp.----->| Router sends Destination Up
| Response.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects change in logical | Modem detects change in logical
| destination metrics, and sends | destination metrics, and sends
|<-------Destination Update------| Destination Update message. |<-------Destination Update------| Destination Update message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects change in logical | Modem detects change in logical
| destination metrics, and sends | destination metrics, and sends
|<-------Destination Update------| Destination Update message. |<-------Destination Update------| Destination Update message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects logical destination | Modem detects logical destination
| is no longer reachable, and sends | is no longer reachable, and sends
|<-------Destination Down--------| Destination Down message. |<-------Destination Down--------| Destination Down message.
| |
| Router receives Destination Down, | Router receives Destination Down,
| updates internal state, and sends | updates internal state, and sends
|------Destination Down Resp.--->| Destination Down Response message. |------Destination Down Resp.--->| Destination Down Response message.
C.2. Multicast Destination Signaling C.2. Multicast Destination Notification
Router Modem Message Description
Router Modem Signal Description
======================================================================== ========================================================================
| Router detects a new multicast | Router detects a new multicast
| destination is in use, and sends | destination is in use, and sends
|--------Destination Up--------->| Destination Up message. |--------Destination Up--------->| Destination Up message.
| |
| Modem updates internal state to | Modem updates internal state to
| monitor multicast destination, and | monitor multicast destination, and
|<-----Destination Up Resp.------| sends Destination Up Response. |<-----Destination Up Resp.------| sends Destination Up Response.
skipping to change at page 62, line 31 skipping to change at page 67, line 28
|<-------Destination Update------| Destination Update message. |<-------Destination Update------| Destination Update message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Modem detects change in multicast | Modem detects change in multicast
| destination metrics, and sends | destination metrics, and sends
|<-------Destination Update------| Destination Update message. |<-------Destination Update------| Destination Update message.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
| Router detects multicast | Router detects multicast
| destination is no longer in use, | destination is no longer in use,
|--------Destination Down------->| and sends Destination Down message. |--------Destination Down------->| and sends Destination Down
| message.
| |
| Modem receives Destination Down, | Modem receives Destination Down,
| updates internal state, and sends | updates internal state, and sends
|<-----Destination Down Resp.----| Destination Down Response message. |<-----Destination Down Resp.----| Destination Down Response message.
C.3. Link Characteristics Request C.3. Link Characteristics Request
Router Modem Signal Description Router Modem Message Description
======================================================================== ========================================================================
Destination has already been Destination has already been
~ ~ ~ ~ ~ ~ ~ announced by either peer. ~ ~ ~ ~ ~ ~ ~ announced by either peer.
| Router requires different | Router requires different
| Characteristics for the | Characteristics for the
| destination, and sends Link | destination, and sends Link
|--Link Characteristics Request->| Characteristics Request message. |--Link Characteristics Request->| Characteristics Request message.
| |
skipping to change at page 63, line 31 skipping to change at page 68, line 31
Authors' Addresses Authors' Addresses
Stan Ratliff Stan Ratliff
VT iDirect VT iDirect
13861 Sunrise Valley Drive, Suite 300 13861 Sunrise Valley Drive, Suite 300
Herndon, VA 20171 Herndon, VA 20171
USA USA
Email: sratliff@idirect.net Email: sratliff@idirect.net
Bo Berry
Shawn Jury Shawn Jury
Cisco Systems Cisco Systems
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
USA USA
Email: sjury@cisco.com Email: sjury@cisco.com
Darryl Satterwhite Darryl Satterwhite
Broadcom Broadcom
skipping to change at line 2860 skipping to change at page 69, line 13
Email: dsatterw@broadcom.com Email: dsatterw@broadcom.com
Rick Taylor Rick Taylor
Airbus Defence & Space Airbus Defence & Space
Quadrant House Quadrant House
Celtic Springs Celtic Springs
Coedkernew Coedkernew
Newport NP10 8FZ Newport NP10 8FZ
UK UK
Email: rick.taylor@airbus.com Email: rick.taylor@airbus.com
Bo Berry
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