draft-ietf-manet-dlep-20.txt   draft-ietf-manet-dlep-21.txt 
Mobile Ad hoc Networks Working Group S. Ratliff Mobile Ad hoc Networks Working Group S. Ratliff
Internet-Draft VT iDirect Internet-Draft VT iDirect
Intended status: Standards Track B. Berry Intended status: Standards Track B. Berry
Expires: September 9, 2016 Expires: September 22, 2016
S. Jury S. Jury
Cisco Systems Cisco Systems
D. Satterwhite D. Satterwhite
Broadcom Broadcom
R. Taylor R. Taylor
Airbus Defence & Space Airbus Defence & Space
March 8, 2016 March 21, 2016
Dynamic Link Exchange Protocol (DLEP) Dynamic Link Exchange Protocol (DLEP)
draft-ietf-manet-dlep-20 draft-ietf-manet-dlep-21
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 44
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 9, 2016. This Internet-Draft will expire on September 22, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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skipping to change at page 2, line 26 skipping to change at page 2, line 26
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 7 1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 7
2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 7 2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 7
2.1. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 9 2.1. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 9
3. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4. DLEP Session Flow . . . . . . . . . . . . . . . . . . . . . . 10 4. DLEP Session Flow . . . . . . . . . . . . . . . . . . . . . . 10
4.1. Peer Discovery State . . . . . . . . . . . . . . . . . . 11 4.1. Peer Discovery State . . . . . . . . . . . . . . . . . . 11
4.2. Session Initialization State . . . . . . . . . . . . . . 12 4.2. Session Initialization State . . . . . . . . . . . . . . 11
4.3. In-Session State . . . . . . . . . . . . . . . . . . . . 12 4.3. In-Session State . . . . . . . . . . . . . . . . . . . . 12
4.3.1. Heartbeats . . . . . . . . . . . . . . . . . . . . . 13 4.3.1. Heartbeats . . . . . . . . . . . . . . . . . . . . . 12
4.4. Session Termination State . . . . . . . . . . . . . . . . 13 4.4. Session Termination State . . . . . . . . . . . . . . . . 13
4.5. Session Reset state . . . . . . . . . . . . . . . . . . . 13 4.5. Session Reset state . . . . . . . . . . . . . . . . . . . 13
4.5.1. Unexpected TCP connection termination . . . . . . . . 14 4.5.1. Unexpected TCP connection termination . . . . . . . . 14
5. Transaction Model . . . . . . . . . . . . . . . . . . . . . . 14 5. Transaction Model . . . . . . . . . . . . . . . . . . . . . . 14
6. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 15 6. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.1. Experiments . . . . . . . . . . . . . . . . . . . . . . . 15 6.1. Experiments . . . . . . . . . . . . . . . . . . . . . . . 15
7. Scalability . . . . . . . . . . . . . . . . . . . . . . . . . 16 7. Scalability . . . . . . . . . . . . . . . . . . . . . . . . . 16
8. DLEP Signal and Message Structure . . . . . . . . . . . . . . 16 8. DLEP Signal and Message Structure . . . . . . . . . . . . . . 16
8.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 17 8.1. DLEP Signal Header . . . . . . . . . . . . . . . . . . . 16
8.2. DLEP Message Header . . . . . . . . . . . . . . . . . . . 17 8.2. DLEP Message Header . . . . . . . . . . . . . . . . . . . 17
8.3. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 18 8.3. DLEP Generic Data Item . . . . . . . . . . . . . . . . . 17
9. DLEP Signals and Messages . . . . . . . . . . . . . . . . . . 18 9. DLEP Signals and Messages . . . . . . . . . . . . . . . . . . 18
9.1. General Processing Rules . . . . . . . . . . . . . . . . 20 9.1. General Processing Rules . . . . . . . . . . . . . . . . 19
9.2. Status code processing . . . . . . . . . . . . . . . . . 20 9.2. Status code processing . . . . . . . . . . . . . . . . . 20
9.3. Peer Discovery Signal . . . . . . . . . . . . . . . . . . 21 9.3. Peer Discovery Signal . . . . . . . . . . . . . . . . . . 21
9.4. Peer Offer Signal . . . . . . . . . . . . . . . . . . . . 21 9.4. Peer Offer Signal . . . . . . . . . . . . . . . . . . . . 21
9.5. Session Initialization Message . . . . . . . . . . . . . 22 9.5. Session Initialization Message . . . . . . . . . . . . . 22
9.6. Session Initialization Response Message . . . . . . . . . 23 9.6. Session Initialization Response Message . . . . . . . . . 22
9.7. Session Update Message . . . . . . . . . . . . . . . . . 24 9.7. Session Update Message . . . . . . . . . . . . . . . . . 24
9.8. Session Update Response Message . . . . . . . . . . . . . 25 9.8. Session Update Response Message . . . . . . . . . . . . . 25
9.9. Session Termination Message . . . . . . . . . . . . . . . 26 9.9. Session Termination Message . . . . . . . . . . . . . . . 25
9.10. Session Termination Response Message . . . . . . . . . . 26 9.10. Session Termination Response Message . . . . . . . . . . 26
9.11. Destination Up Message . . . . . . . . . . . . . . . . . 26 9.11. Destination Up Message . . . . . . . . . . . . . . . . . 26
9.12. Destination Up Response Message . . . . . . . . . . . . . 27 9.12. Destination Up Response Message . . . . . . . . . . . . . 27
9.13. Destination Announce Message . . . . . . . . . . . . . . 28 9.13. Destination Announce Message . . . . . . . . . . . . . . 28
9.14. Destination Announce Response Message . . . . . . . . . . 29 9.14. Destination Announce Response Message . . . . . . . . . . 28
9.15. Destination Down Message . . . . . . . . . . . . . . . . 30 9.15. Destination Down Message . . . . . . . . . . . . . . . . 30
9.16. Destination Down Response Message . . . . . . . . . . . . 30 9.16. Destination Down Response Message . . . . . . . . . . . . 30
9.17. Destination Update Message . . . . . . . . . . . . . . . 31 9.17. Destination Update Message . . . . . . . . . . . . . . . 30
9.18. Link Characteristics Request Message . . . . . . . . . . 32 9.18. Link Characteristics Request Message . . . . . . . . . . 32
9.19. Link Characteristics Response Message . . . . . . . . . . 33 9.19. Link Characteristics Response Message . . . . . . . . . . 32
9.20. Heartbeat Message . . . . . . . . . . . . . . . . . . . . 34 9.20. Heartbeat Message . . . . . . . . . . . . . . . . . . . . 33
10. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 34 10. DLEP Data Items . . . . . . . . . . . . . . . . . . . . . . . 34
10.1. Status . . . . . . . . . . . . . . . . . . . . . . . . . 35 10.1. Status . . . . . . . . . . . . . . . . . . . . . . . . . 35
10.2. IPv4 Connection Point . . . . . . . . . . . . . . . . . 37 10.2. IPv4 Connection Point . . . . . . . . . . . . . . . . . 37
10.3. IPv6 Connection Point . . . . . . . . . . . . . . . . . 38 10.3. IPv6 Connection Point . . . . . . . . . . . . . . . . . 37
10.4. Peer Type . . . . . . . . . . . . . . . . . . . . . . . 39 10.4. Peer Type . . . . . . . . . . . . . . . . . . . . . . . 39
10.5. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 39 10.5. Heartbeat Interval . . . . . . . . . . . . . . . . . . . 39
10.6. Extensions Supported . . . . . . . . . . . . . . . . . . 40 10.6. Extensions Supported . . . . . . . . . . . . . . . . . . 40
10.7. MAC Address . . . . . . . . . . . . . . . . . . . . . . 41 10.7. MAC Address . . . . . . . . . . . . . . . . . . . . . . 40
10.8. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 41 10.8. IPv4 Address . . . . . . . . . . . . . . . . . . . . . . 41
10.9. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 42 10.9. IPv6 Address . . . . . . . . . . . . . . . . . . . . . . 42
10.10. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 43 10.10. IPv4 Attached Subnet . . . . . . . . . . . . . . . . . . 43
10.11. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 44 10.11. IPv6 Attached Subnet . . . . . . . . . . . . . . . . . . 44
10.12. Maximum Data Rate (Receive) . . . . . . . . . . . . . . 45 10.12. Maximum Data Rate (Receive) . . . . . . . . . . . . . . 45
10.13. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 46 10.13. Maximum Data Rate (Transmit) . . . . . . . . . . . . . . 45
10.14. Current Data Rate (Receive) . . . . . . . . . . . . . . 46 10.14. Current Data Rate (Receive) . . . . . . . . . . . . . . 46
10.15. Current Data Rate (Transmit) . . . . . . . . . . . . . . 47 10.15. Current Data Rate (Transmit) . . . . . . . . . . . . . . 47
10.16. Latency . . . . . . . . . . . . . . . . . . . . . . . . 48 10.16. Latency . . . . . . . . . . . . . . . . . . . . . . . . 48
10.17. Resources . . . . . . . . . . . . . . . . . . . . . . . 48 10.17. Resources . . . . . . . . . . . . . . . . . . . . . . . 48
10.18. Relative Link Quality (Receive) . . . . . . . . . . . . 49 10.18. Relative Link Quality (Receive) . . . . . . . . . . . . 49
10.19. Relative Link Quality (Transmit) . . . . . . . . . . . . 50 10.19. Relative Link Quality (Transmit) . . . . . . . . . . . . 50
10.20. Maximum Transmission Unit (MTU) . . . . . . . . . . . . 50 10.20. Maximum Transmission Unit (MTU) . . . . . . . . . . . . 50
11. Security Considerations . . . . . . . . . . . . . . . . . . . 51 11. Security Considerations . . . . . . . . . . . . . . . . . . . 51
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 52 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 52
12.1. Registrations . . . . . . . . . . . . . . . . . . . . . 52 12.1. Registrations . . . . . . . . . . . . . . . . . . . . . 52
12.2. Signal Type Registration . . . . . . . . . . . . . . . . 53 12.2. Signal Type Registration . . . . . . . . . . . . . . . . 52
12.3. Message Type Registration . . . . . . . . . . . . . . . 53 12.3. Message Type Registration . . . . . . . . . . . . . . . 52
12.4. DLEP Data Item Registrations . . . . . . . . . . . . . . 53 12.4. DLEP Data Item Registrations . . . . . . . . . . . . . . 53
12.5. DLEP Status Code Registrations . . . . . . . . . . . . . 53 12.5. DLEP Status Code Registrations . . . . . . . . . . . . . 54
12.6. DLEP Extensions Registrations . . . . . . . . . . . . . 53 12.6. DLEP Extensions Registrations . . . . . . . . . . . . . 54
12.7. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 54 12.7. DLEP Well-known Port . . . . . . . . . . . . . . . . . . 55
12.8. DLEP IPv4 Link-local Multicast Address . . . . . . . . . 54 12.8. DLEP IPv4 Link-local Multicast Address . . . . . . . . . 55
12.9. DLEP IPv6 Link-local Multicast Address . . . . . . . . . 54 12.9. DLEP IPv6 Link-local Multicast Address . . . . . . . . . 55
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 54 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 55
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 54 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 55
14.1. Normative References . . . . . . . . . . . . . . . . . . 54 14.1. Normative References . . . . . . . . . . . . . . . . . . 55
14.2. Informative References . . . . . . . . . . . . . . . . . 55 14.2. Informative References . . . . . . . . . . . . . . . . . 56
Appendix A. Discovery Signal Flows . . . . . . . . . . . . . . . 55 Appendix A. Discovery Signal Flows . . . . . . . . . . . . . . . 56
Appendix B. Peer Level Message Flows . . . . . . . . . . . . . . 56 Appendix B. Peer Level Message Flows . . . . . . . . . . . . . . 57
B.1. Session Initialization . . . . . . . . . . . . . . . . . 56 B.1. Session Initialization . . . . . . . . . . . . . . . . . 57
B.2. Session Initialization - Refused . . . . . . . . . . . . 56 B.2. Session Initialization - Refused . . . . . . . . . . . . 57
B.3. Router Changes IP Addresses . . . . . . . . . . . . . . . 57 B.3. Router Changes IP Addresses . . . . . . . . . . . . . . . 58
B.4. Modem Changes Session-wide Metrics . . . . . . . . . . . 57 B.4. Modem Changes Session-wide Metrics . . . . . . . . . . . 58
B.5. Router Terminates Session . . . . . . . . . . . . . . . . 58 B.5. Router Terminates Session . . . . . . . . . . . . . . . . 59
B.6. Modem Terminates Session . . . . . . . . . . . . . . . . 58 B.6. Modem Terminates Session . . . . . . . . . . . . . . . . 59
B.7. Session Heartbeats . . . . . . . . . . . . . . . . . . . 58 B.7. Session Heartbeats . . . . . . . . . . . . . . . . . . . 59
B.8. Router Detects a Heartbeat timeout . . . . . . . . . . . 59 B.8. Router Detects a Heartbeat timeout . . . . . . . . . . . 60
B.9. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 59 B.9. Modem Detects a Heartbeat timeout . . . . . . . . . . . . 60
Appendix C. Destination Specific Message Flows . . . . . . . . . 60 Appendix C. Destination Specific Message Flows . . . . . . . . . 61
C.1. Common Destination Notification . . . . . . . . . . . . . 60 C.1. Common Destination Notification . . . . . . . . . . . . . 61
C.2. Multicast Destination Notification . . . . . . . . . . . 61 C.2. Multicast Destination Notification . . . . . . . . . . . 62
C.3. Link Characteristics Request . . . . . . . . . . . . . . 61 C.3. Link Characteristics Request . . . . . . . . . . . . . . 62
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 62 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 63
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
datarate vary with respect to individual destinations on a link, and datarate vary with respect to individual destinations on a link, and
with the type of traffic being sent. As an example, consider the with the type of traffic being sent. As an example, consider the
case of an 802.11 access point, serving two associated laptop case of an IEEE 802.11 access point, serving two associated laptop
computers. In this environment, the answer to the question "What is computers. In this environment, the answer to the question "What is
the datarate on the 802.11 link?" is "It depends on which associated the datarate on the 802.11 link?" is "It depends on which associated
laptop we're talking about, and on what kind of traffic is being laptop we're talking about, and on what kind of traffic is being
sent." While the first laptop, being physically close to the access sent." While the first laptop, being physically close to the access
point, may have a datarate of 54Mbps for unicast traffic, the other point, may have a datarate of 54Mbps for unicast traffic, the other
laptop, being relatively far away, or obstructed by some object, can laptop, being relatively far away, or obstructed by some object, can
simultaneously have a datarate of only 32Mbps for unicast. However, simultaneously have a datarate of only 32Mbps for unicast. However,
for multicast traffic sent from the access point, all traffic is sent for multicast traffic sent from the access point, all traffic is sent
at the base transmission rate (which is configurable, but depending at the base transmission rate (which is configurable, but depending
on the model of the access point, is usually 24Mbps or less). on the model of the access point, is usually 24Mbps or less).
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 IP routing protocols tend to
on interface state and independent timers at OSI Layer 3 to maintain rely on interface state and independent timers to maintain network
network convergence (e.g., HELLO messages and/or recognition of DEAD convergence (e.g., HELLO messages and/or recognition of DEAD routing
routing adjacencies). These dynamic connections can be better adjacencies). These dynamic connections can be better utilized with
utilized with an event-driven paradigm, where acquisition of a new an event-driven paradigm, where acquisition of a new neighbor (or
neighbor (or loss of an existing one) is signaled, as opposed to a loss of an existing one) is signaled, as opposed to a paradigm driven
paradigm driven by timers and/or interface state. DLEP not only by timers and/or interface state. DLEP not only implements such an
implements such an event-driven paradigm, but does so over a local (1 event-driven paradigm, but does so over a local (1 hop) TCP session,
hop) TCP session, which guarantees delivery of the event messages. 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
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2. Protocol Overview 2. Protocol Overview
DLEP defines a set of Messages used by modems and their attached DLEP defines a set of Messages used by modems and their attached
routers to communicate events that occur on the physical link(s) routers to communicate events that occur on the physical link(s)
managed by the modem: for example, a remote node entering or leaving managed by the modem: for example, a remote node entering or leaving
the network, or that the link has changed. Associated with these the network, or that the link has changed. Associated with these
Messages are a set of Data Items - information that describes the Messages are a set of Data Items - information that describes the
remote node (e.g., address information), and/or the characteristics remote node (e.g., address information), and/or the characteristics
of the link to the remote node. Throughout this document, we refer of the link to the remote node. Throughout this document, we refer
to a modems/routers participating in a DLEP session as 'DLEP Peers', to a modems/routers participating in a DLEP session as 'DLEP
or 'DLEP Participants', unless a specific distinction (e.g. modem or Participants', unless a specific distinction (e.g. modem or router)
router) is required. is required.
DLEP uses a session-oriented paradigm between the modem device and DLEP uses a session-oriented paradigm between the modem device and
its associated router. If multiple modem devices are attached to a its associated router. If multiple modem devices are attached to a
router (as in Figure 2), or the modem supports multiple connections router (as in Figure 2), or the modem supports multiple connections
(via multiple logical or physical interfaces), then separate DLEP (via multiple logical or physical interfaces), then separate DLEP
sessions exist for each modem or connection. A router and modem form sessions exist for each modem or connection. A router and modem form
a session by completing the discovery and initialization process. a session by completing the discovery and initialization process.
This router-modem session persists unless or until it either (1) This router-modem session persists unless or until it either (1)
times out, based on the absence of DLEP traffic (including times out, based on the absence of DLEP traffic (including
heartbeats), or (2) is explicitly torn down by one of the DLEP heartbeats), or (2) is explicitly torn down by one of the DLEP
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Destinations can be identified by either the router or the modem, and Destinations can be identified by either the router or the modem, and
represent a specific, addressable location that can be reached via represent a specific, addressable location that can be reached via
the link(s) managed by the modem. the link(s) managed by the modem.
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 destinations information base representing the physical and logical destinations
accessible via the modem device, as well as the link characteristics accessible via the modem device, as well as the link characteristics
to those destinations. to those destinations.
DLEP indentifies destinations by using the MAC address for delivering DLEP identifies destinations by using the MAC address for delivering
data traffic. No manipulation or substitution is performed; the MAC data traffic. No manipulation or substitution is performed; the MAC
address supplied in all destination Messages is used as the OSI Layer address supplied in all destination Messages is used as the
2 Destination MAC address. DLEP therefore requires that MAC Destination MAC address. DLEP therefore requires that MAC addresses
addresses are unique within the context of a router-modem session. are unique within the context of a router-modem session.
The reliance on MAC addresses by DLEP forces the requirement that The reliance on MAC addresses by DLEP forces the requirement that
participating DLEP peers are on a single segment (either physical or DLEP participants are on a single segment (either physical or
logically, via tunneling protocols) at Layer 2. logically, via tunneling protocols) at Layer 2.
A destination can be either physical or logical. The example of a A destination can be either physical or logical. The example of a
physical destination would be that of a remote, far-end router physical destination would be that of a remote, far-end router
attached via the variable-quality network. It should be noted that attached via the variable-quality network. It should be noted that
for physical destinations the MAC address is the address of the far- for physical destinations the MAC address is the address of the far-
end router, not the modem. end router, not the modem.
The example of a logical destination is Multicast. Multicast traffic The example of a logical destination is Multicast. Multicast traffic
destined for the variable-quality network (the network accessed via destined for the variable-quality network (the network accessed via
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logical destination. The modem, once it is aware of the existence of logical destination. The modem, once it is aware of the existence of
this logical destination, reports link characteristics just as it this logical destination, reports link characteristics just as it
would for any other destination in the network. The specific would for any other destination in the network. The specific
algorithms a modem would use to derive metrics on logical algorithms a modem would use to derive metrics on logical
destinations are outside the scope of this specification, and is left destinations are outside the scope of this specification, and is left
to specific implementations to decide. to specific implementations to decide.
While this document represents the best efforts of the working group While this document represents the best efforts of the working group
to be functionally complete, it is recognized that extensions to DLEP to be functionally complete, it is recognized that extensions to DLEP
will in all likelihood be necessary as more link types are used. will in all likelihood be necessary as more link types are used.
Such extensions are defined as additional rules of behavior, Such extensions are defined as additional Messages, Data Items and/or
Messages, Data Items and/or status codes that are not defined in this status codes, and associated rules of behavior, that are not defined
document. DLEP contains a standard mechanism for router and modem in this document. DLEP contains a standard mechanism for router and
implementations to negotiate the available extensions to use on a modem implementations to negotiate the available extensions to use on
per-session basis. a per-session basis.
2.1. Assumptions 2.1. Assumptions
DLEP specifies UDP multicast for single-hop discovery signaling, and DLEP specifies UDP multicast for single-hop discovery signaling, and
TCP for transport of the Messages. Therefore, DLEP assumes that the TCP for transport of the Messages. Therefore, DLEP assumes that the
modem and router have topologically consistent IP addresses assigned. modem and router have topologically consistent IP addresses assigned.
It is RECOMMENDED that DLEP implementations utilize IPv6 link-local It is RECOMMENDED that DLEP implementations utilize IPv6 link-local
addresses to reduce the administrative burden of address assignment. addresses to reduce the administrative burden of address assignment.
DLEP relies on the guaranteed- delivery of its Messages between DLEP relies on the guaranteed- delivery of its Messages between
router and modem, once the 1 hop discovery process is complete, router and modem, once the 1 hop discovery process is complete,
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the variable-quality link in use. DLEP does not specify how a given the variable-quality link in use. DLEP does not specify how a given
metric value is to be calculated, rather, the protocol assumes that metric value is to be calculated, rather, the protocol assumes that
metrics have been calculated by a 'best effort', incorporating all metrics have been calculated by a 'best effort', incorporating all
pertinent data that is available to the modem device. pertinent data that is available to the modem device.
DLEP allows for metrics to be sent within two contexts - metrics for DLEP allows for metrics to be sent within two contexts - metrics for
a specific destination within the network (e.g., a specific router), a specific destination within the network (e.g., a specific router),
and per-session (those that apply to all destinations accessed via and per-session (those that apply to all destinations accessed via
the modem). Most metrics can be further subdivided into transmit and the modem). Most metrics can be further subdivided into transmit and
receive metrics. In cases where metrics are provided at session receive metrics. In cases where metrics are provided at session
level, the router MUST propagate the metrics to all entries in its level, the router propagates the metrics to all entries in its
information base for destinations that are accessed via the modem. information base for destinations that are accessed via the modem.
DLEP modem implementations MUST announce all metric Data Items that DLEP modems announce all metric Data Items that will be reported
will be reported during the session, and provide default values for during the session, and provide default values for those metrics, in
those metrics, in the Session Initialization Response Message the Session Initialization Response Message (Section 9.6). In order
(Section 9.6). In order to use a metric type that was not included to use a metric type that was not included in the Session
in the Session Initialization Response Message, modem implementations Initialization Response Message, modem implementations terminate the
MUST terminate the session with the router (via the Session Terminate session with the router (via the Session Terminate Message
Message (Section 9.9)), and establish a new session. (Section 9.9)), and establish a new session.
A DLEP modem MAY send metrics both in a session context (via the A DLEP modem can send metrics both in a session context, via the
Session Update Message) and a specific destination context (via Session Update Message (Section 9.7), and a specific destination
Destination Update) at any time. The most recently received metric context, via the Destination Update Message (Section 9.17), at any
value MUST take precedence over any earlier value, regardless of time. The most recently received metric value takes precedence over
context - that is: any earlier value, regardless of context - that is:
1. If the router receives metrics in a specific destination context 1. If the router receives metrics in a specific destination context
(via the Destination Update Message), then the specific (via the Destination Update Message), then the specific
destination is updated with the new metric. destination is updated with the new metric.
2. If the router receives metrics in a session-wide context (via the 2. If the router receives metrics in a session-wide context (via the
Session Update Message), then the metrics for all destinations Session Update Message), then the metrics for all destinations
accessed via the modem MUST be updated with the new metric. accessed via the modem are updated with the new metric.
It is left to implementations to choose sensible default values based It is left to implementations to choose sensible default values based
on their specific characteristics. Modems having static (non- on their specific characteristics. Modems having static (non-
changing) link metric characteristics MAY report metrics only once changing) link metric characteristics can report metrics only once
for a given destination (or once on a session-wide basis, if all for a given destination (or once on a session-wide basis, if all
connections via the modem are of this static nature). connections via the modem are of this static nature).
In addition to communicating existing metrics about the link, DLEP In addition to communicating existing metrics about the link, DLEP
provides a Message allowing a router to request a different datarate provides a Message allowing a router to request a different datarate
or latency from the modem. This Message is the Link Characteristics or latency from the modem. This Message is the Link Characteristics
Request Message (Section 9.18), and gives the router the ability to Request Message (Section 9.18), and gives the router the ability to
deal with requisite increases (or decreases) of allocated datarate/ deal with requisite increases (or decreases) of allocated datarate/
latency in demand-based schemes in a more deterministic manner. latency in demand-based schemes in a more deterministic manner.
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Modems, and routers supporting DLEP discovery, transition through all Modems, and routers supporting DLEP discovery, transition through all
five (5) of the above states. Routers that rely on preconfigured TCP five (5) of the above states. Routers that rely on preconfigured TCP
address/port information start in the Session Initialization state. address/port information start in the Session Initialization state.
Modems MUST support the Peer Discovery state. Modems MUST support the Peer Discovery state.
4.1. Peer Discovery State 4.1. Peer Discovery State
In the Peer Discovery state, routers that support DLEP discovery MUST In the Peer Discovery state, routers that support DLEP discovery MUST
send UDP packets containing a Peer Discovery Signal (Section 9.3) to send Peer Discovery Signals (Section 9.3) to initiate modem
the DLEP well-known address and port number. For routers supporting discovery.
both IPv4 and IPv6 DLEP operation, it is RECOMMENDED that IPv6 be
selected as the transport.
The router implementation then waits for a unicast UDP packet The router implementation then waits for a Peer Offer Signal
containing a Peer Offer Signal (Section 9.4) from a potential DLEP (Section 9.4) response from a potential DLEP modem. While in the
peer modem. While in the Peer Discovery state, Peer Discovery Peer Discovery state, Peer Discovery Signals MUST be sent repeatedly
Signals MUST be sent repeatedly by a DLEP router, at regular by a DLEP router, at regular intervals. The interval MUST be a
intervals. The interval MUST be a minimum of one second; it SHOULD minimum of one second; it SHOULD be a configurable parameter. Note
be a configurable parameter. Note that this operation (sending Peer that this operation (sending Peer Discovery and waiting for Peer
Discovery and waiting for Peer Offer) is outside the DLEP Transaction Offer) is outside the DLEP Transaction Model (Section 5), as the
Model, as the Transaction Model only describes Messages on a TCP Transaction Model only describes Messages on a TCP session.
session.
Routers MUST use one or more of the modem address/port combinations Routers MUST use one or more of each of the modem address/port
from the Peer Offer Signal or from a priori configuration to combinations from the Peer Offer Signal or, when no Connection Point
establish a new TCP connection to the modem. If more than one modem Data Items are present, from a priori configuration to establish a
address/port combinations is available, router implementations MAY new TCP connection to the modem. If more than one modem address/port
use their own heuristics to determine the order in which they are combinations is provided, router implementations MAY use their own
tried. If a TCP connection cannot be achieved using any of the heuristics to determine the order in which they are tried. If a TCP
address/port combinations and the Discovery mechanism is in use, then connection cannot be achieved using any of the address/port
the router SHOULD resume issuing Peer Discovery Signals. If no IPv4 combinations and the Discovery mechanism is in use, then the router
Connection Point Data Items, nor IPv6 Connection Point Data Items are SHOULD resume issuing Peer Discovery Signals. If no Connection Point
included in the Peer Offer Signal, the router MUST use the source Data Items are included in the Peer Offer Signal, the router MUST use
address of the UDP packet containing the Signal as the IP address, the source address of the UDP packet containing the Signal as the IP
and the DLEP well-known port number. address, and the DLEP well-known port number.
In the Peer Discovery state, the modem implementation MUST listen for In the Peer Discovery state, the modem implementation MUST listen for
incoming Peer Discovery Signals on the DLEP well-known link-local incoming Peer Discovery Signals on the DLEP well-known IPv6 and/or
multicast address and port. On receipt of a valid Peer Discovery IPv4 link-local multicast address and port. On receipt of a valid
Signal, it MUST unicast a Peer Offer Signal to the source address and Peer Discovery Signal, it MUST reply with a Peer Offer Signal.
port of the received UDP packet.
Modems MUST be prepared to accept a TCP connection from a router that Modems MUST be prepared to accept a TCP connection from a router that
is not using the Discovery mechanism, i.e. a connection attempt that is not using the Discovery mechanism, i.e. a connection attempt that
occurs without a preceding Peer Discovery Signal. occurs without a preceding Peer Discovery Signal.
Upon establishment of a TCP connection, both modem and router enter Upon establishment of a TCP connection, both modem and router enter
the Session Initialization state. It is up to the router the Session Initialization state. It is up to the router
implementation if Peer Discovery Signals continue to be sent after implementation if Peer Discovery Signals continue to be sent after
the device has transitioned to the Session Initialization state. the device has transitioned to the Session Initialization state.
Modem implementations MUST silently ignore Peer Discovery Signals Modem implementations MUST silently ignore Peer Discovery Signals
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receipt of a Session Initialization Message from the router. Upon receipt of a Session Initialization Message from the router. Upon
receipt of a Session Initialization Message, the modem MUST send a receipt of a Session Initialization Message, the modem MUST send a
Session Initialization Response Message, and the session MUST Session Initialization Response Message, and the session MUST
transition to the In-Session state. If the modem receives any transition to the In-Session state. If the modem receives any
Message other than Session Initialization, or it fails to parse the Message other than Session Initialization, or it fails to parse the
received Message, it MUST NOT send any Message, and MUST terminate received Message, it MUST NOT send any Message, and MUST terminate
the TCP connection and transition to the Session Reset state. the TCP connection and transition to the Session Reset state.
DLEP provides an extension negotiation capability to be used in the DLEP provides an extension negotiation capability to be used in the
Session Initialization state, see Section 6. Extensions supported by Session Initialization state, see Section 6. Extensions supported by
an implementation MUST be declared to potential DLEP peers using the an implementation MUST be declared to potential DLEP participants
Extensions Supported Data Item (Section 10.6). Once both DLEP peers using the Extensions Supported Data Item (Section 10.6). Once both
have exchanged initialization Messages, an implementation MUST NOT DLEP participants have exchanged initialization Messages, an
emit 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.
4.3. In-Session State 4.3. In-Session State
In the In-Session state, Messages can flow in both directions between In the In-Session state, Messages can flow in both directions between
DLEP peers, indicating changes to the session state, the arrival or DLEP participants, indicating changes to the session state, the
departure of reachable destinations, or changes of the state of the arrival or departure of reachable destinations, or changes of the
links to the destinations. state of the links to the destinations.
The In-Session state is maintained until one of the following The In-Session state is maintained until one of the following
conditions occur: conditions occur:
o The implementation terminates the session by sending a Session o The implementation terminates the session by sending a Session
Termination Message (Section 9.9)), or, Termination Message (Section 9.9), or,
o The peer terminates the session, indicated by receiving a Session o Its peer terminates the session, indicated by receiving a Session
Termination Message. Termination Message.
The implementation MUST then transition to the Session Termination The implementation MUST then transition to the Session Termination
state. state.
4.3.1. Heartbeats 4.3.1. Heartbeats
In order to maintain the In-Session state, periodic Heartbeat In order to maintain the In-Session state, periodic Heartbeat
Messages (Section 9.20) MUST be exchanged between router and modem. Messages (Section 9.20) MUST be exchanged between router and modem.
These Messages are intended to keep the session alive, and to verify These Messages are intended to keep the session alive, and to verify
bidirectional connectivity between the two DLEP peers. bidirectional connectivity between the two DLEP participants.
Each DLEP participant is responsible for the creation of Heartbeat Each DLEP participant is responsible for the creation of Heartbeat
Messages. Messages.
Receipt of any valid DLEP Message MUST reset the heartbeat interval Receipt of any valid DLEP Message MUST reset the heartbeat interval
timer (i.e., valid DLEP Messages take the place of, and obviate the timer (i.e., valid DLEP Messages take the place of, and obviate the
need for, additional Heartbeat Messages). need for, additional Heartbeat Messages).
Implementations SHOULD allow two (2) heartbeat intervals to expire Implementations MUST allow a minimum of two (2) heartbeat intervals
with no Messages from the peer before terminating the session by to expire with no Messages from its peer before terminating the
issuing a Session Termination Message containing a Status Data Item session. When terminating the session, a Session Termination Message
(Section 10.1) with status code set to 5 'Timed Out', see Table 4, containing a Status Data Item (Section 10.1) with status code set to
and then transition to the Session Termination state. 132 'Timed Out', see Table 4, MUST be sent, and then the
implementation MUST transition to the Session Termination state.
4.4. Session Termination State 4.4. Session Termination State
When an implementation enters the Session Termination state after When an implementation enters the Session Termination state after
sending a Session Termination Message (Section 9.9) as the result of sending a Session Termination Message (Section 9.9) as the result of
an invalid Message or error, it MUST wait for a Session Termination an invalid Message or error, it MUST wait for a Session Termination
Response Message (Section 9.10) from its peer. Senders SHOULD allow Response Message (Section 9.10) from its peer. Senders SHOULD allow
four (4) heartbeat intervals to expire before assuming that the peer four (4) heartbeat intervals to expire before assuming that its peer
is unresponsive, and continuing with session termination. Any other is unresponsive, and continuing with session termination. Any other
Message received while waiting MUST be silently ignored. Message received while waiting MUST be silently ignored.
When the sender of the Session Termination Message receives a Session When the sender of the Session Termination Message receives a Session
Termination Response Message from its peer, or times out, it MUST Termination Response Message from its peer, or times out, it MUST
transition to the Session Reset state. transition to the Session Reset state.
When an implementation enters the Session Termination state having When an implementation receives a Session Termination Message from
received a Session Termination Message from its peer, it MUST its peer, it enters the Session Termination state and then it MUST
immediately send a Session Termination Response and transition to the immediately send a Session Termination Response and transition to the
Session Reset state. Session Reset state.
4.5. Session Reset state 4.5. Session Reset state
In the Session Reset state the implementation MUST perform the In the Session Reset state the implementation MUST perform the
following actions: following actions:
o Release all resources allocated for the session. o Release all resources allocated for the session.
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o Terminate the TCP connection. o Terminate the TCP connection.
Having completed these actions the implementation SHOULD return to Having completed these actions the implementation SHOULD return to
the relevant initial state: Peer Discovery for modems; either Peer the relevant initial state: Peer Discovery for modems; either Peer
Discovery or Session Initialization for routers, depending on Discovery or Session Initialization for routers, depending on
configuration. configuration.
4.5.1. Unexpected TCP connection termination 4.5.1. Unexpected TCP connection termination
If the TCP connection between DLEP peers is terminated when an If the TCP connection between DLEP participants is terminated when an
implementation is not in the Session Reset state, the implementation implementation is not in the Session Reset state, the implementation
MUST immediately transition to the Session Reset state. MUST immediately transition to the Session Reset state.
5. Transaction Model 5. Transaction Model
DLEP defines a simple Message transaction model: Only one request per DLEP defines a simple Message transaction model: Only one request per
destination may be in progress at a time per session. A Message destination may be in progress at a time per session. A Message
transaction is considered complete when a response matching a transaction is considered complete when a response matching a
previously issued request is received. If a DLEP participant previously issued request is received. If a DLEP participant
receives a request for a destination for which there is already an receives a request for a destination for which there is already an
outstanding request, the implementation MUST terminate the session by outstanding request, the implementation MUST terminate the session by
issuing a Session Termination Message (Section 9.9) containing a issuing a Session Termination Message (Section 9.9) containing a
Status Data Item (Section 10.1) with status code set to 2 'Unexpected Status Data Item (Section 10.1) with status code set to 129
Message', see Table 4, and transition to the Session Termination 'Unexpected Message', see Table 4, and transition to the Session
state. There is no restriction to the total number of Message Termination state. There is no restriction to the total number of
transactions in progress at a time, as long as each transaction Message transactions in progress at a time, as long as each
refers to a different destination. transaction refers to a different destination.
It should be noted that some requests may take a considerable amount It should be noted that some requests may take a considerable amount
of time for some DLEP participants to complete, for example a modem of time for some DLEP participants to complete, for example a modem
handling a multicast destination up request may have to perform a handling a multicast destination up request may have to perform a
complex network reconfiguration. A sending implementation MUST be complex network reconfiguration. A sending implementation MUST be
able to handle such long running transactions gracefully. able to handle such long running transactions gracefully.
Additionally, only one session request, e.g. a Session Initialization Additionally, only one session request, e.g. a Session Initialization
Message (Section 9.5), may be in progress at a time per session. As Message (Section 9.5), may be in progress at a time per session. As
above, a session transaction is considered complete when a response above, a session transaction is considered complete when a response
matching a previously issued request is received. If a DLEP matching a previously issued request is received. If a DLEP
participant receives a session request while there is already a participant receives a session request while there is already a
session request in progress, it MUST terminate the session by issuing session request in progress, it MUST terminate the session by issuing
a Session Termination Message containing a Status Data Item with a Session Termination Message containing a Status Data Item with
status code set to 2 'Unexpected Message', and transition to the status code set to 129 'Unexpected Message', and transition to the
Session Termination state. Only the Session Termination Message may Session Termination state. Only the Session Termination Message may
be issued when a session transaction is in progress. Heartbeat be issued when a session transaction is in progress. Heartbeat
Messages (Section 9.20) MUST NOT be considered part of a session Messages (Section 9.20) MUST NOT be considered part of a session
transaction. transaction.
DLEP transactions do not time out and are not cancellable. An DLEP transactions do not time out and are not cancellable. An
implementation can detect if its peer has failed in some way by use implementation can detect if its peer has failed in some way by use
of the session heartbeat mechanism during the In-Session state, see of the session heartbeat mechanism during the In-Session state, see
Section 4.3. Section 4.3.
6. Extensions 6. Extensions
Extensions MUST be negotiated on a per-session basis during session Extensions MUST be negotiated on a per-session basis during session
initialization via the Extensions Supported mechanism. initialization via the Extensions Supported mechanism.
Implementations are not required to support any extension in order to Implementations are not required to support any extension in order to
be considered DLEP compliant. An extension document, describing the be considered DLEP compliant. An extension document, describing the
operation of a credit windowing scheme for flow control, is described operation of a credit windowing scheme for flow control, is described
in [CREDIT]. in [CREDIT].
If interoperable protocol extensions are required, they MUST be If interoperable protocol extensions are required, they will need to
standardized either as an update to this document, or as an be 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 need to 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 6.1. Experiments
This document requests Private Use numbering space in the DLEP This document requests Private Use numbering space in the DLEP
Signal, Message, Data Item and status code registries for Signal, Message, Data Item and status code registries for
experimental extensions. The intent is to allow for experimentation experimental extensions. The intent is to allow for experimentation
with new Signals, Messages, Data Items, and/or status codes, while with new Signals, Messages, Data Items, and/or status codes, while
still retaining the documented DLEP behavior. still retaining the documented DLEP behavior.
Use of the Private Use Signals, Messages, Data Items, status codes, Use of the Private Use Signals, Messages, Data Items, status codes,
or behaviors MUST be announced as DLEP Extensions, during session or behaviors MUST be announced as DLEP Extensions, during session
initialization, using extension identifiers from the Private Use initialization, using extension identifiers from the Private Use
space in the Extensions Supported registry (Table 5), with a value space in the Extensions Supported registry (Table 5), with a value
agreed upon (a priori) between the participating peers. DLEP agreed upon (a priori) between the participants. DLEP extensions
extensions using the Private Use numbering space are commonly using the Private Use numbering space are commonly referred to as
referred to as Experiments. Experiments.
Multiple experiments MAY be announced in the Session Initialization Multiple experiments MAY be announced in the Session Initialization
Messages. However, use of multiple experiments in a single session Messages. However, use of multiple experiments in a single session
could lead to interoperability issues or unexpected results (e.g., could lead to interoperability issues or unexpected results (e.g.,
clashes of experimental Signals, Messages, Data Items and/or status clashes of experimental Signals, Messages, Data Items and/or status
code types), and is therefore discouraged. It is left to code types), and is therefore discouraged. It is left to
implementations to determine the correct processing path (e.g., a implementations to determine the correct processing path (e.g., a
decision on whether to terminate the session, or to establish a decision on whether to terminate the session, or to establish a
precedence of the conflicting definitions) if such conflicts arise. precedence of the conflicting definitions) if such conflicts arise.
7. Scalability 7. Scalability
The protocol is intended to support thousands of destinations on a The protocol is intended to support thousands of destinations on a
given modem/router pair. At large scale, implementations SHOULD given modem/router pair. At large scale, implementations SHOULD
consider employing techniques to prevent flooding a peer with a large consider employing techniques to prevent flooding its peer with a
number of Messages in a short time. It is recommended that large 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.
techniques such as a hysteresis to lessen the impact of rapid, minor
fluctuations in link quality. The specific algorithms to be used for Implementations SHOULD also consider techniques such as a hysteresis
handling flapping destinations and minor changes in link quality are to lessen the impact of rapid, minor fluctuations in link quality.
outside the scope of this specification. The specific algorithms to be used for handling flapping destinations
and minor changes in link quality are outside the scope of this
specification.
8. DLEP Signal and Message Structure 8. DLEP Signal and Message Structure
DLEP defines two protocol units used in two different ways: Signals DLEP defines two protocol units used in two different ways: Signals
and Messages. Signals are only used in the Discovery mechanism and and Messages. Signals are only used in the Discovery mechanism and
are carried in UDP datagrams. Messages are used bi-directionally are carried in UDP datagrams. Messages are used bi-directionally
over a TCP connection between two peers, in the Session over a TCP connection between the participants, in the Session
Initialization, In-Session and Session Termination states. Initialization, In-Session and Session Termination states.
Both Signals and Messages consist of a Header followed by an Both Signals and Messages consist of a Header followed by an
unordered list of Data Items. Headers consist of Type and Length unordered list of Data Items. Headers consist of Type and Length
information, while Data Items are encoded as TLV (Type-Length-Value) information, while Data Items are encoded as TLV (Type-Length-Value)
structures. In this document, the Data Items following a Signal or structures. In this document, the Data Items following a Signal or
Message Header are described as being 'contained in' the Signal or Message Header are described as being 'contained in' the Signal or
Message. Message.
There is no restriction on the order of Data Items following a There is no restriction on the order of Data Items following a
Header, and the multiplicity of duplicate Data Items is defined by Header, and the acceptability 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 8.1. DLEP Signal Header
The DLEP Signal Header contains the following fields: The DLEP Signal Header contains the following fields:
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Figure 3: DLEP Signal Header Figure 3: DLEP Signal Header
"DLEP": Every Signal MUST start with the characters: U+0044, U+004C, "DLEP": Every Signal MUST start with the characters: U+0044, U+004C,
U+0045, U+0050. U+0045, U+0050.
Signal Type: A 16-bit unsigned integer containing one of the DLEP Signal Type: A 16-bit unsigned integer containing one of the DLEP
Signal Type values defined in this document. Signal Type values defined in this document.
Length: The length in octets, expressed as a 16-bit unsigned Length: The length in octets, expressed as a 16-bit unsigned
integer, of all of the DLEP Data Items associated with this integer, of all of the DLEP Data Items contained in this Signal.
Signal. This length MUST NOT include the length of the Signal This length MUST NOT include the length of the Signal Header
Header itself. itself.
The DLEP Signal Header is immediately followed by zero or more DLEP The DLEP Signal Header is immediately followed by zero or more DLEP
Data Items, encoded in TLVs, as defined in this document. Data Items, encoded in TLVs, as defined in this document.
8.2. DLEP Message Header 8.2. DLEP Message Header
The DLEP Message Header contains the following fields: The DLEP Message Header contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Length | | Message Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: DLEP Message Header Figure 4: DLEP Message Header
Message Type: A 16-bit unsigned integer containing one of the DLEP Message Type: A 16-bit unsigned integer containing one of the DLEP
Message Type values defined in this document. Message Type values defined in this document.
Length: The length in octets, expressed as a 16-bit unsigned Length: The length in octets, expressed as a 16-bit unsigned
integer, of all of the DLEP Data Items associated with this integer, of all of the DLEP Data Items contained in this Message.
Message. This length MUST NOT include the length of the Message This length MUST NOT include the length of the Message Header
Header itself. itself.
The DLEP Message Header is immediately followed by zero or more DLEP The DLEP Message Header is immediately followed by zero or more DLEP
Data Items, encoded in TLVs, as defined in this document. Data Items, encoded in TLVs, as defined in this document.
8.3. DLEP Generic Data Item 8.3. DLEP Generic Data Item
All DLEP Data Items contain the following fields: All DLEP Data Items contain the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
skipping to change at page 18, line 34 skipping to change at page 18, line 27
Length: The length in octets, expressed as a 16-bit unsigned Length: The length in octets, expressed as a 16-bit unsigned
integer, of the Value field of the Data Item. This length MUST integer, of the Value field of the Data Item. This length MUST
NOT include the length of the Data Item Type and Length fields. NOT include the length of the Data Item Type and Length fields.
Value: A field of <Length> octets, which contains data specific to a Value: A field of <Length> octets, which contains data specific to a
particular Data Item. particular Data Item.
9. DLEP Signals and Messages 9. DLEP Signals and Messages
As mentioned above, all DLEP Signals begin with the DLEP Signal
Header, and all DLEP Messages begin with the DLEP Message Header.
Therefore, in the following descriptions of specific Signals and
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 Signals and Messages when received.
The core DLEP Signals are: The core DLEP Signals are:
+--------------+-----------------------------------------+ +--------------+-----------------------------------------+
| Type Code | Description | | Type Code | Description |
+--------------+-----------------------------------------+ +--------------+-----------------------------------------+
| 0 | Reserved | | 0 | Reserved |
| 1 | Peer Discovery Signal (Section 9.3) | | 1 | Peer Discovery Signal (Section 9.3) |
| 2 | Peer Offer Signal (Section 9.4) | | 2 | Peer Offer Signal (Section 9.4) |
| 3-65519 | Reserved for future extensions | | 3-65519 | Reserved for future extensions |
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| 65520-65534 | Private Use. Available for experiments | | 65520-65534 | Private Use. Available for experiments |
| 65535 | Reserved | | 65535 | Reserved |
+-------------------+-----------------------------------------------+ +-------------------+-----------------------------------------------+
Table 2: DLEP Message types Table 2: DLEP Message types
9.1. General Processing Rules 9.1. General Processing Rules
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 DLEP peer MUST ignore the Signal. Items, the receiving implementation MUST ignore the Signal.
If an unrecognized Message is received, the receiving DLEP peer MUST If an unrecognized Message is received, the receiving implementation
issue a Session Termination Message (Section 9.9) containing a Status MUST issue a Session Termination Message (Section 9.9) containing a
Data Item (Section 10.1) with status code set to 1 'Unknown Message', Status Data Item (Section 10.1) with status code set to 128 'Unknown
see Table 4, and transition to the Session Termination state. Message', see Table 4, and transition to the Session Termination
state.
If an unexpected Message is received, the receiving DLEP peer MUST If an unexpected Message is received, the receiving implementation
issue a Session Termination Message containing a Status Data Item MUST issue a Session Termination Message containing a Status Data
with status code set to 2 'Unexpected Message', and transition to the Item with status code set to 129 'Unexpected Message', and transition
Session Termination state. to the Session Termination state.
If a received Message contains unrecognized, invalid, or disallowed If a received Message contains unrecognized, invalid, or disallowed
duplicate Data Items, the receiving DLEP peer MUST issue a Session duplicate Data Items, the receiving implementation MUST issue a
Termination Message containing a Status Data Item with status code Session Termination Message containing a Status Data Item with status
set to 3 'Invalid Data', and transition to the Session Termination code set to 130 'Invalid Data', and transition to the Session
state. Termination state.
Prior to the exchange of Destination Up (Section 9.11) and Prior to the exchange of Destination Up (Section 9.11) and
Destination Up Response (Section 9.12) Messages, or Destination Destination Up Response (Section 9.12) Messages, or Destination
Announce (Section 9.13) and Destination Announce Response Announce (Section 9.13) and Destination Announce Response
(Section 9.14) Messages, no Messages concerning a destination may be (Section 9.14) Messages, no Messages concerning a destination may be
sent. A peer receiving any Message with such an unannounced sent. An implementation receiving any Message with such an
destination MUST terminate the session by issuing a Session unannounced destination MUST terminate the session by issuing a
Termination Message containing a Status Data Item with status code Session Termination Message containing a Status Data Item with status
set to 4 'Invalid Destination', and transition to the Session code set to 131 'Invalid Destination', and transition to the Session
Termination state. Termination state.
After exchanging Destination Down (Section 9.15) and Destination Down After exchanging Destination Down (Section 9.15) and Destination Down
Response (Section 9.16) Messages, no Messages concerning a Response (Section 9.16) Messages, no Messages concerning a
destination may be a sent until a new Destination Up or Destination destination may be a sent until a new Destination Up or Destination
Announce Message is sent. A peer receiving a Message about a Announce Message is sent. An implementation receiving a Message
destination previously announced as 'down' MUST terminate the session about a destination previously announced as 'down' MUST terminate the
by issuing a Session Termination Message with a Status Data Item with session by issuing a Session Termination Message with a Status Data
status code set to 4 'Invalid Destination', and transition to the Item with status code set to 131 'Invalid Destination', and
Session Termination state. transition to the Session Termination state.
9.2. Status code processing 9.2. Status code processing
The behaviour of a DLEP participant receiving a Message containing a The behaviour of a DLEP participant receiving a Message containing a
Status Data Item (Section 10.1) is defined by the failure mode Status Data Item (Section 10.1) is defined by the failure mode
associated with the value of the status code field, see Table 4. associated with the value of the status code field, see Table 4. All
Except for the reserved value of 255, all status code values greater status code values less than 100 have a failure mode of 'Continue',
than or equal to 100 have a failure mode of 'Continue', all other all other status codes have a failure mode of 'Terminate'.
status codes have a failure mode of 'Terminate'.
A DLEP participant receiving any Message apart from Session A DLEP participant receiving any Message apart from Session
Termination Message (Section 9.9) containing a Status Data Item with Termination Message (Section 9.9) containing a Status Data Item with
a status code value with failure mode 'Terminate' MUST immediately a status code value with failure mode 'Terminate' MUST immediately
issue a Session Termination Message containing an identical Status issue a Session Termination Message containing an identical Status
Data Item, and then transition to the Session Termination state. Data Item, and then transition to the Session Termination state.
A DLEP participant receiving a Message containing a Status Data Item A DLEP participant receiving a Message containing a Status Data Item
with a status code value with failure mode 'Continue' can continue with a status code value with failure mode 'Continue' can continue
normal operation of the session. normal operation of the session.
9.3. Peer Discovery Signal 9.3. Peer Discovery Signal
A Peer Discovery Signal SHOULD be sent by a DLEP router to discover A Peer Discovery Signal SHOULD be sent by a DLEP router to discover
DLEP modems in the network. DLEP modems in the network Section 4.1.
A Peer Discovery Signal MUST be encoded within a UDP packet. The
destination MUST be set to the DLEP well-known address and port
number. For routers supporting both IPv4 and IPv6 DLEP operation, it
is RECOMMENDED that IPv6 be selected as the transport. The source IP
address MUST be set to the router IP address associated with the DLEP
interface. There is no DLEP-specific restriction on source port.
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 a Peer Type Data Item The Peer Discovery Signal MAY contain a Peer Type Data Item
(Section 10.4). (Section 10.4).
Implementations MUST implement their own retransmit heuristics in
cases where it is determined the Peer Discovery Signal has timed out.
9.4. Peer Offer Signal 9.4. Peer Offer Signal
A Peer Offer Signal MUST be sent by a DLEP modem to the unicast A Peer Offer Signal MUST be sent by a DLEP modem in response to a
address of the originator of a valid Peer Discovery Signal properly formatted and addressed Peer Discovery Signal (Section 9.3).
(Section 9.3). The Peer Offer Signal is completes the discovery
process. A Peer Offer Signal MUST be encoded within a UDP packet. The IP
destination MUST be set to the IP address and port number received in
the corresponding Peer Discovery Signal. The source IP address MUST
be set to the modem's IP address associated with the DLEP interface.
The source port number MUST be set to the DLEP well-known port
number. The Peer Offer Signal completes the discovery process
Section 4.1.
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 a Peer Type Data Item The Peer Offer Signal MAY contain a Peer Type Data Item
(Section 10.4). (Section 10.4).
The Peer Offer Signal MAY contain one or more of any of the following The Peer Offer Signal MAY contain one or more of any of the following
Data Items, with different values: Data Items, with different values:
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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 a Peer Type Data Item The Peer Offer Signal MAY contain a Peer Type Data Item
(Section 10.4). (Section 10.4).
The Peer Offer Signal MAY contain one or more of any of the following The Peer Offer Signal MAY contain one or more of any of the following
Data Items, with different values: Data Items, with different values:
o IPv4 Connection Point (Section 10.2) o IPv4 Connection Point (Section 10.2)
o IPv6 Connection Point (Section 10.3) o IPv6 Connection Point (Section 10.3)
The IP Connection Point Data Items indicate the unicast address the The IP Connection Point Data Items indicate the unicast address the
router MUST use when connecting the DLEP TCP session. If multiple IP router MUST use when connecting the DLEP TCP session.
Connection Point Data Items are present in the Peer Offer Signal,
router implementations MAY use their own heuristics to select the
address to connect to. If no IP Connection Point Data Items are
included in the Peer Offer Signal, the router MUST use the source
address of the Signal as the IP address, and the DLEP well-known port
number (Section 12.7) to establish the TCP connection.
9.5. Session Initialization Message 9.5. Session Initialization Message
A Session Initialization Message MUST be sent by a DLEP 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.
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 1, from Table 2. in the Message Header is set to 1, from Table 2.
skipping to change at page 22, line 41 skipping to change at page 22, line 31
o Peer Type (Section 10.4) o Peer Type (Section 10.4)
o Extensions Supported (Section 10.6) o Extensions Supported (Section 10.6)
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 modem MUST conclude that there is no Initialization Message, the modem MUST conclude that there is no
support for extensions in the router. support for extensions in the router.
DLEP Heartbeats are not fully established until receipt of Session DLEP Heartbeats are not fully established until receipt of the
Initialization Response Message (Section 9.6), and therefore Session Initialization Response Message (Section 9.6), and therefore
implementations must use their own timeout and retry heuristics for implementations MUST use their own timeout and retry heuristics for
this Message. this Message.
As an exception to the general rule governing an implementation As an exception to the general rule governing an implementation
receiving an unrecognized Data Item in a Message, see Section 9.1, if receiving an unrecognized Data Item in a Message, see Section 9.1, if
a Session Initialization Message contains one or more Extension a Session Initialization Message contains one or more Extension
Supported Data Items announcing support for extensions that the Supported Data Items announcing support for extensions that the
implementation does not recognize, then the implementation MAY ignore implementation does not recognize, then the implementation MAY ignore
Data Items it does not recognize. Data Items it does not recognize.
9.6. Session Initialization Response Message 9.6. Session Initialization Response Message
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router and modem. router and 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 router MUST conclude that there is no support Response Message, the router MUST conclude that there is no support
for extensions in the modem. 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 DLEP peers. use extensions that are supported by both DLEP participants
Section 4.2.
9.7. Session Update Message 9.7. Session Update Message
A Session Update Message MAY be sent by a DLEP participant to A Session Update Message MAY be sent by a DLEP participant to
indicate local Layer 3 address changes, or metric changes on a indicate local Layer 3 address changes, or metric changes on a
session-wide basis. session-wide basis.
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 3, from Table 2. Message Header is set to 3, from Table 2.
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Data Items, if the Data Item is in use by the session: Data Items, if the Data Item is in use by the session:
o Resources (Section 10.17) o Resources (Section 10.17)
o Relative Link Quality (Receive) (Section 10.18) o Relative Link Quality (Receive) (Section 10.18)
o Relative Link Quality (Transmit) (Section 10.19) o Relative Link Quality (Transmit) (Section 10.19)
o Maximum Transmission Unit (MTU) (Section 10.20) o Maximum Transmission Unit (MTU) (Section 10.20)
The Session Update Message MAY contain one or more of the following The Session Update Message MAY contain one or more of each of the
Data Items, with different values: following Data Items, with different values:
o IPv4 Address (Section 10.8) o IPv4 Address (Section 10.8)
o IPv6 Address (Section 10.9) o IPv6 Address (Section 10.9)
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 session-wide, Maximum Data Rate), these metrics are considered to be session-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 DLEP session. base associated with the DLEP session. This includes destinations
for which metrics may have been stored based on received Destination
Update messages.
It should be noted that Session Update Messages can be sent by both It should be noted that Session Update Messages can be sent by both
routers and modems. For example, addition of an IPv4 address to the routers and modems. For example, addition of an IPv4 address to the
router MAY prompt a Session Update Message to its attached modems. router MAY prompt a Session Update Message to its attached modems.
Also, for example, a modem that changes its Maximum Data Rate Also, for example, a modem that changes its Maximum Data Rate
(Receive) for all destinations MAY reflect that change via a Session (Receive) for all destinations MAY reflect that change via a Session
Update Message to its attached router(s). 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 9.17) to their local routers with the new (or Message (Section 9.17) 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 ignore Address Data Items. SHOULD silently ignore Address Data Items.
9.8. Session Update Response Message 9.8. Session Update Response Message
A Session Update Response Message MUST be sent by by a DLEP A Session Update Response Message MUST be sent by a DLEP participant
participant when a Session Update Message (Section 9.7) is received. when a Session Update Message (Section 9.7) is 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 4, from Table 2. value in the Message Header is set to 4, from Table 2.
The Session Update Response Message MUST contain a Status Data Item The Session Update Response Message MUST contain a Status Data Item
(Section 10.1). (Section 10.1).
9.9. Session Termination Message 9.9. Session Termination Message
A Session Termination Message MUST be sent by a DLEP participant when A Session Termination Message MUST be sent by a DLEP participant when
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The Session Termination Message MUST contain Status Data Item The Session Termination Message MUST contain Status Data Item
(Section 10.1). (Section 10.1).
It should be noted that Session Termination Messages can be sent by It should be noted that Session Termination Messages can be sent by
both routers and modems. both routers and modems.
9.10. Session Termination Response Message 9.10. Session Termination Response Message
A Session Termination Response Message MUST be sent by a DLEP A Session Termination Response Message MUST be sent by a DLEP
participant when a Session Termination Message (Section 9.9) is participant when a Session Termination Message (Section 9.9) is
recevied. received.
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 6, from Table 2. value in the Message Header is set to 6, from Table 2.
There are no valid Data Items for the Session Termination Response There are no valid Data Items for the Session Termination Response
Message. Message.
Receipt of a Session Termination Response Message completes the tear- Receipt of a Session Termination Response Message completes the tear-
down of the DLEP session. down of the DLEP session Section 4.4.
9.11. Destination Up Message 9.11. Destination Up Message
Destination Up Messages are sent by a modem to inform its attached Destination Up Messages MAY be sent by a modem to inform its attached
router of the presence of a new reachable destination. router of the presence of a new reachable destination.
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 7, from Table 2. Message Header is set to 7, from Table 2.
The Destination Up Message MUST contain a MAC Address Data Item The Destination Up Message MUST contain a MAC Address Data Item
(Section 10.7). (Section 10.7).
The Destination Up Message SHOULD contain one or more of the The Destination Up Message SHOULD contain one or more of each of the
following Data Items, with different values: following Data Items, with different values:
o IPv4 Address (Section 10.8) o IPv4 Address (Section 10.8)
o IPv6 Address (Section 10.9) o IPv6 Address (Section 10.9)
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 10.12)
o Maximum Data Rate (Transmit) (Section 10.13) o Maximum Data Rate (Transmit) (Section 10.13)
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 10.15)
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Data Items, if the Data Item is in use by the session: Data Items, if the Data Item is in use by the session:
o Resources (Section 10.17) o Resources (Section 10.17)
o Relative Link Quality (Receive) (Section 10.18) o Relative Link Quality (Receive) (Section 10.18)
o Relative Link Quality (Transmit) (Section 10.19) o Relative Link Quality (Transmit) (Section 10.19)
o Maximum Transmission Unit (MTU) (Section 10.20) o Maximum Transmission Unit (MTU) (Section 10.20)
The Destination Up Message MAY contain one or more of the following The Destination Up Message MAY contain one or more of each of the
Data Items, with different values: following Data Items, with different values:
o IPv4 Attached Subnet (Section 10.10) o IPv4 Attached Subnet (Section 10.10)
o IPv6 Attached Subnet (Section 10.11) o IPv6 Attached Subnet (Section 10.11)
A router receiving a Destination Up Message allocates the necessary A router receiving a Destination Up Message allocates the necessary
resources, creating an entry in the information base with the resources, creating an entry in the information base with the
specifics (i.e. MAC Address, Latency, Data Rate, etc.) of the specifics (MAC Address, Latency, Data Rate, etc.) of the destination.
destination. The information about this destination will persist in The information about this destination will persist in the router's
the router's information base until a Destination Down Message information base until a Destination Down Message (Section 9.15) is
(Section 9.15) is received, indicating that the modem has lost received, indicating that the modem has lost contact with the remote
contact with the remote node, or the implementation transitions to node, or the implementation transitions to the Session Termination
the Session Termination state. state.
9.12. Destination Up Response Message 9.12. Destination Up Response Message
A router MUST send a Destination Up Response Message when a A router MUST send a Destination Up Response Message when a
Destination Up Message (Section 9.11) is received. Destination Up Message (Section 9.11) is received.
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 8, from Table 2. value in the Message Header is set to 8, from Table 2.
The Destination Up Response Message MUST contain one of each of the The Destination Up Response Message MUST contain one of each of the
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o Status (Section 10.1) o Status (Section 10.1)
A router that wishes to receive further information concerning the A router that wishes to receive further information concerning the
destination identified in the corresponding Destination Up Message destination identified in the corresponding Destination Up Message
MUST set the status code of the included Status Data Item to 0 MUST set the status code of the included Status Data Item to 0
'Success', see Table 4. 'Success', see Table 4.
If the router has no interest in the destination identified in the If the router has no interest in the destination identified in the
corresponding Destination Up Message, then it MAY set the status code corresponding Destination Up Message, then it MAY set the status code
of the included Status Data Item to 100 'Not Interested'. of the included Status Data Item to 1 'Not Interested'.
A modem receiving a Destination Up Response Message containing a A modem receiving a Destination Up Response Message containing a
Status Data Item with status code of any value other than 0 'Success' Status Data Item with status code of any value other than 0 'Success'
MUST NOT send further Destination messages about the destination, MUST NOT send further Destination messages about the destination,
e.g. Destination Down (Section 9.15) or Destination Update e.g. Destination Down (Section 9.15) or Destination Update
(Section 9.17) with the same MAC address. (Section 9.17) with the same MAC address.
9.13. Destination Announce Message 9.13. Destination Announce Message
Usually a modem will discover the presence of one or more remote Usually a modem will discover the presence of one or more remote
router/modem pairs and announce each destination's arrival by sending router/modem pairs and announce each destination's arrival by sending
a corresponding Destination Up Message (Section 9.11) to the router. a corresponding Destination Up Message (Section 9.11) to the router.
However, there may be times when a router wishes to express an However, there may be times when a router wishes to express an
interest in a destination that has yet to be announced, typically a interest in a destination that has yet to be announced, typically a
multicast destination. Destination Announce Messages MAY be sent by multicast destination. Destination Announce Messages MAY be sent by
a router to announce such an interest. a router to announce such an interest.
A Destination Announce Message MAY also be used by a router to A Destination Announce Message MAY also be sent by a router to
request information concerning a destination in which it has request information concerning a destination in which it has
previously declined interest, via the 100 'Not Interested' status previously declined interest, via the 1 'Not Interested' status code
code in a Destination Up Response Message (Section 9.12), see Table in a Destination Up Response Message (Section 9.12), see Table 4, or
4, or declared as 'down', via the Destination Down Message declared as 'down', via the Destination Down Message (Section 9.15).
(Section 9.15).
To construct a Destination Announce Message, the Message Type value To construct a Destination Announce Message, the Message Type value
in the Message Header is set to 9, from Table 2. in the Message Header is set to 9, from Table 2.
The Destination Announce Message MUST contain a MAC Address Data Item The Destination Announce Message MUST contain a MAC Address Data Item
(Section 10.7). (Section 10.7).
The Destination Announce Message MAY contain zero or more of the The Destination Announce Message MAY contain zero or more of the
following Data Items, with different values: following Data Items, with different values:
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o Latency (Section 10.16) o Latency (Section 10.16)
The Destination Announce Response Message MAY contain one of each of The Destination Announce Response Message MAY contain one of each of
the following Data Items, if the Data Item is in use by the session: the following Data Items, if the Data Item is in use by the session:
o Resources (Section 10.17) o Resources (Section 10.17)
o Relative Link Quality (Receive) (Section 10.18) o Relative Link Quality (Receive) (Section 10.18)
o Relative Link Quality (Transmit) (Section 10.19) o Relative Link Quality (Transmit) (Section 10.19)
o Maximum Transmission Unit (MTU) (Section 10.20) o Maximum Transmission Unit (MTU) (Section 10.20)
If a modem is unable to report information immediately about the If a modem is unable to report information immediately about the
requested information, if the destination is not currently reachable, requested information, if the destination is not currently reachable,
for example, the status code in the Status Data Item MUST be set to for example, the status code in the Status Data Item MUST be set to 2
101 'Request Denied', see Table 4. 'Request Denied', see Table 4.
After sending a Destination Announce Response Message containing a After sending a Destination Announce Response Message containing a
Status Data Item with status code of 0 'Success', a modem then Status Data Item with status code of 0 'Success', a modem then
announces changes to the link to the destination via Destination announces changes to the link to the destination via Destination
Update Messages. Update Messages.
When a successful Destination Announce Response Message is received, When a successful Destination Announce Response Message is received,
the router should add knowledge of the available destination to its the router should add knowledge of the available destination to its
information base. information base.
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A router MAY send a Destination Down Message to report when it no A router MAY send a Destination Down Message to report when it no
longer requires information concerning a destination. longer requires information concerning a destination.
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 2. the Message Header is set to 11, from Table 2.
The Destination Down Message MUST contain a MAC Address Data Item The Destination Down Message MUST contain a MAC Address Data Item
(Section 10.7). (Section 10.7).
It should be noted that both modem and router may send a Destination It should be noted that both modem and router may send a Destination
Down Message to their peer, regardless of which peer initially Down Message to their peer, regardless of which participant initially
indicated the destination to be 'up'. indicated the destination to be 'up'.
9.16. Destination Down Response Message 9.16. Destination Down Response Message
A Destination Down Response MUST be sent by the recipient of a A Destination Down Response MUST be sent by the recipient of a
Destination Down Message (Section 9.15) to confirm that the relevant Destination Down Message (Section 9.15) to confirm that the relevant
data concerning the destination has been removed from the information data concerning the destination has been removed from the information
base. base.
To construct a Destination Down Response Message, the Message Type To construct a Destination Down Response Message, the Message Type
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following Data Items, if the Data Item is in use by the session: following Data Items, if the Data Item is in use by the session:
o Resources (Section 10.17) o Resources (Section 10.17)
o Relative Link Quality (Receive) (Section 10.18) o Relative Link Quality (Receive) (Section 10.18)
o Relative Link Quality (Transmit) (Section 10.19) o Relative Link Quality (Transmit) (Section 10.19)
o Maximum Transmission Unit (MTU) (Section 10.20) o Maximum Transmission Unit (MTU) (Section 10.20)
The Destination Update Message MAY contain one or more of the The Destination Update Message MAY contain one or more of each of the
following Data Items, with different values: following Data Items, with different values:
o IPv4 Address (Section 10.8) o IPv4 Address (Section 10.8)
o IPv6 Address (Section 10.9) o IPv6 Address (Section 10.9)
o IPv4 Attached Subnet (Section 10.10) o IPv4 Attached Subnet (Section 10.10)
o IPv6 Attached Subnet (Section 10.11) o IPv6 Attached Subnet (Section 10.11)
If metrics are supplied with the Message (e.g., Resources), these
metrics are MUST be applied to all destinations identified in the
Message. Note that this may overwrite metrics provided in a
previously received Session or Destination Up Messages.
It should be noted that this Message has no corresponding response. It should be noted that this Message has no corresponding response.
9.18. Link Characteristics Request Message 9.18. Link Characteristics Request Message
The Link Characteristics Request Message MAY be sent by a router to The Link Characteristics Request Message MAY be sent by a router to
request that the modem initiate changes for specific characteristics request that the modem initiate changes for specific characteristics
of the link. The request can reference either a real destination of the link. The request can reference either a real destination
(e.g., a remote node), or a logical destination (e.g., a multicast (e.g., a remote node), or a logical destination (e.g., a multicast
group) within the network. group) within the network.
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each of the following Data Items: each of the following Data Items:
o Current Data Rate (Receive) (Section 10.14) o Current Data Rate (Receive) (Section 10.14)
o Current Data Rate (Transmit) (Section 10.15) o Current Data Rate (Transmit) (Section 10.15)
o Latency (Section 10.16) o Latency (Section 10.16)
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 is currently allocated, a Latency Data Item to request that
traffic delay on the link not exceed the specified value, or both. traffic delay on the link not exceed the specified value, or both.
The router sending a Link Characteristics Request Message should be The router sending a Link Characteristics Request Message should be
aware that a request may take an extended period of time to complete. aware that a request may take an extended period of time to complete.
9.19. Link Characteristics Response Message 9.19. Link Characteristics Response Message
A modem MUST send a Link Characteristics Response Message when a Link A modem MUST send a Link Characteristics Response Message when a Link
Characteristics Request Message (Section 9.18) is received. Characteristics Request Message (Section 9.18) is received.
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The Link Characteristics Response Message MUST contain a complete set The Link Characteristics Response Message MUST contain a complete set
of metric Data Items, referencing all metrics declared in the Session of metric Data Items, referencing all metrics declared in the Session
Initialization Response Message (Section 9.6). The values in the Initialization Response Message (Section 9.6). The values in the
metric Data Items in the Link Characteristics Response Message MUST metric Data Items in the Link Characteristics Response Message MUST
reflect the link characteristics after the request has been reflect the link characteristics after the request has been
processed. 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 the status code of the Status Data link in the manner requested, then the status code of the Status Data
Item MUST be set to 101 'Request Denied', see Table 4. Item MUST be set to 2 'Request Denied', see Table 4.
9.20. Heartbeat Message 9.20. Heartbeat Message
A Heartbeat Message MUST be sent by a DLEP participant every N A Heartbeat Message MUST be sent by a DLEP participant every N
milliseconds, where N is defined in the Heartbeat Interval Data Item milliseconds, where N is defined in the Heartbeat Interval Data Item
(Section 10.5) of the Session Initialization Message (Section 9.5) or (Section 10.5) of the Session Initialization Message (Section 9.5) or
Session Initialization Response Message (Section 9.6). Session Initialization Response Message (Section 9.6).
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 16, from Table 2. Message Header is set to 16, from Table 2.
There are no valid Data Items for the Heartbeat Message. There are no valid Data Items for the Heartbeat Message.
The Message is used by DLEP peers to detect when a DLEP session peer The Message is used by DLEP participants to detect when a DLEP
(either the modem or the router) is no longer communicating. DLEP session peer (either the modem or the router) is no longer
participants SHOULD allow two (2) heartbeat intervals to expire with communicating Section 4.3.1.
no Messages from the DLEP peer before initiating DLEP session
termination procedures.
10. DLEP Data Items 10. DLEP Data Items
Following is the list of core Data Items that MUST be recognized by a Following is the list of core Data Items that MUST be recognized by a
DLEP compliant implementation. As mentioned before, not all Data DLEP compliant implementation. As mentioned before, not all Data
Items need be used during a session, but an implementation MUST Items need be used during a session, but an implementation MUST
correctly process these Data Items when correctly associated with a correctly process these Data Items when correctly associated with a
Signal or Message. Signal or Message.
The core DLEP Data Items are: The core DLEP Data Items are:
skipping to change at page 34, line 52 skipping to change at page 34, line 34
| 2 | IPv4 Connection Point (Section 10.2) | | 2 | IPv4 Connection Point (Section 10.2) |
| 3 | IPv6 Connection Point (Section 10.3) | | 3 | IPv6 Connection Point (Section 10.3) |
| 4 | Peer Type (Section 10.4) | | 4 | Peer Type (Section 10.4) |
| 5 | Heartbeat Interval (Section 10.5) | | 5 | Heartbeat Interval (Section 10.5) |
| 6 | Extensions Supported (Section 10.6) | | 6 | Extensions Supported (Section 10.6) |
| 7 | MAC Address (Section 10.7) | | 7 | MAC Address (Section 10.7) |
| 8 | IPv4 Address (Section 10.8) | | 8 | IPv4 Address (Section 10.8) |
| 9 | IPv6 Address (Section 10.9) | | 9 | IPv6 Address (Section 10.9) |
| 10 | IPv4 Attached Subnet (Section 10.10) | | 10 | IPv4 Attached Subnet (Section 10.10) |
| 11 | IPv6 Attached Subnet (Section 10.11) | | 11 | IPv6 Attached Subnet (Section 10.11) |
| 12 | Maximum Data Rate (Receive) MDRR) (Section | | 12 | Maximum Data Rate (Receive) (MDRR) (Section |
| | 10.12) | | | 10.12) |
| 13 | Maximum Data Rate (Transmit) (MDRT) (Section | | 13 | Maximum Data Rate (Transmit) (MDRT) (Section |
| | 10.13) | | | 10.13) |
| 14 | Current Data Rate (Receive) (CDRR) (Section | | 14 | Current Data Rate (Receive) (CDRR) (Section |
| | 10.14) | | | 10.14) |
| 15 | Current Data Rate (Transmit) (CDRT) (Section | | 15 | Current Data Rate (Transmit) (CDRT) (Section |
| | 10.15) | | | 10.15) |
| 16 | Latency (Section 10.16) | | 16 | Latency (Section 10.16) |
| 17 | Resources (RES) (Section 10.17) | | 17 | Resources (RES) (Section 10.17) |
| 18 | Relative Link Quality (Receive) (RLQR) | | 18 | Relative Link Quality (Receive) (RLQR) |
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10.1. Status 10.1. Status
For the Session Termination Message (Section 9.9), the Status Data For the Session Termination Message (Section 9.9), the Status Data
Item indicates a reason for the termination. For all response Item indicates a reason for the termination. For all response
Messages, the Status Data Item is used to indicate the success or Messages, the Status Data Item is used to indicate the success or
failure of the previously received Message. failure of the previously received Message.
The Status Data Item includes an optional Text field that can be used The Status Data Item includes an optional Text field that can be used
to provide a textual description of the status. The use of the Text to provide a textual description of the status. The use of the Text
field is entirely up to the receiving implementation, i.e., it could field is entirely up to the receiving implementation, e.g., it could
be output to a log file or discarded. If no Text field is supplied be output to a log file or discarded. If no Text field is supplied
with the Status Data Item, the Length field MUST be set to 1. with the Status Data Item, the Length field MUST be set to 1.
The Status Data Item contains the following fields: The Status Data Item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Text: UTF-8 encoded string of UNICODE [UNIV8] characters, describing Text: UTF-8 encoded string of UNICODE [UNIV8] characters, describing
the cause, used for implementation defined purposes. Since this the cause, used for implementation defined purposes. Since this
field is used for description, implementations SHOULD limit field is used for description, implementations SHOULD limit
characters in this field to printable characters. Implementations characters in this field to printable characters. Implementations
receiving this Data Item SHOULD check for printable characters in receiving this Data Item SHOULD check for printable characters in
the field. the field.
An implementation MUST NOT assume the Text field is NUL-terminated. An implementation MUST NOT assume the Text field is NUL-terminated.
+---------------+---------+-----------+-----------------------------+ +---------+-----------+---------------+-----------------------------+
| Status Code | Value | Failure | Reason | | Status | Failure | Description | Reason |
| | | Mode | | | Code | Mode | | |
+---------------+---------+-----------+-----------------------------+ +---------+-----------+---------------+-----------------------------+
| Success | 0 | Success | The Message was processed | | 0 | Continue | Success | The Message was processed |
| | | | successfully. | | | | | successfully. |
| Unknown | 1 | Terminate | The Message was not | | 1 | Continue | Not | The receiver is not |
| Message | | | recognized by the | | | | Interested | interested in this Message |
| | | | implementation. | | | | | subject, e.g. in a |
| Unexpected | 2 | Terminate | The Message was not | | | | | Destination Up Response |
| Message | | | expected while the device | | | | | Message (Section 9.12) to |
| | | | was in the current state, | | | | | indicate no further |
| | | | e.g., a Session | | | | | Messages about the |
| | | | Initialization Message | | | | | destination. |
| | | | (Section 9.5) in the In- | | 2 | Continue | Request | The receiver refuses to |
| | | | Session state. | | | | Denied | complete the request. |
| Invalid Data | 3 | Terminate | One or more Data Items in | | 3-111 | Continue | <Reserved> | Reserved for future |
| | | | the Message are invalid, | | | | | extensions. |
| | | | unexpected or incorrectly | | 112-127 | Continue | <Private Use> | Available for experiments. |
| | | | duplicated. | | 128 | Terminate | Unknown | The Message was not |
| Invalid | 4 | Terminate | The destination included in | | | | Message | recognized by the |
| Destination | | | the Message does not match | | | | | implementation. |
| | | | a previously announced | | 129 | Terminate | Unexpected | The Message was not |
| | | | destination. For example, | | | | Message | expected while the device |
| | | | in the Link Characteristic | | | | | was in the current state, |
| | | | Response Message (Section | | | | | e.g., a Session |
| | | | 9.19). | | | | | Initialization Message |
| Timed Out | 5 | Terminate | The session has timed out. | | | | | (Section 9.5) in the In- |
| <Reserved> | 6-90 | Terminate | Reserved for future | | | | | Session state. |
| | | | extensions. | | 130 | Terminate | Invalid Data | One or more Data Items in |
| <Private Use> | 91-99 | Terminate | Available for experiments. | | | | | the Message are invalid, |
| Not | 100 | Continue | The receiver is not | | | | | unexpected or incorrectly |
| Interested | | | interested in this Message | | | | | duplicated. |
| | | | subject, e.g. in a | | 131 | Terminate | Invalid | The destination included in |
| | | | Destination Up Response | | | | Destination | the Message does not match |
| | | | Message (Section 9.12) to | | | | | a previously announced |
| | | | indicate no further | | | | | destination. For example, |
| | | | Messages about the | | | | | in the Link Characteristic |
| | | | destination. | | | | | Response Message (Section |
| Request | 101 | Continue | The receiver refuses to | | | | | 9.19). |
| Denied | | | complete the request. | | 132 | Terminate | Timed Out | The session has timed out. |
| <Reserved> | 102-243 | Continue | Reserved for future | | 133-239 | Terminate | <Reserved> | Reserved for future |
| | | | extensions. | | | | | extensions. |
| <Private Use> | 244-254 | Continue | Available for experiments. | | 240-254 | Terminate | <Private Use> | Available for experiments. |
| <Reserved> | 255 | Terminate | Reserved. | | 255 | Terminate | <Reserved> | Reserved. |
+---------------+---------+-----------+-----------------------------+ +---------+-----------+---------------+-----------------------------+
Table 4: DLEP Status Codes Table 4: DLEP Status Codes
10.2. IPv4 Connection Point 10.2. IPv4 Connection Point
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 modem available for optionally, the TCP port number on the modem available for
connections. If provided, the router MUST use this information to connections. If provided, the router MUST use this information to
initiate the TCP connection to the modem. initiate the TCP connection to the modem.
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0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved | | Reserved |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Reserved: MUST be zero. Reserved for future use. Reserved: MUST be zero. Reserved for future use.
10.4. Peer Type 10.4. Peer Type
The Peer Type Data Item is used by the router and modem to give The Peer Type Data Item is used by the router and modem to give
additional information as to its type. The peer type is a string and additional information as to its type. The Peer Type is a string and
is envisioned to be used for informational purposes (e.g., as output is envisioned to be used for informational purposes (e.g., as output
in a display command). in a display command).
The Peer Type Data Item contains the following fields: The Peer Type Data Item contains the following fields:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peer Type... : | Peer Type... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 4 Data Item Type: 4
Length: Length of peer type string, in octets. Length: Length of Peer Type string, in octets.
Peer Type: UTF-8 encoded string of UNICODE [UNIV8] characters. For Peer Type: UTF-8 encoded string of UNICODE [UNIV8] characters. For
example, a satellite modem might set this variable to "Satellite example, a satellite modem might set this variable to "Satellite
terminal". Since this Data Item is intended to provide additional terminal". Since this Data Item is intended to provide additional
information for display commands, sending implementations SHOULD information for display commands, sending implementations SHOULD
limit the data to printable characters, and receiving limit the data to printable characters, and receiving
implementations SHOULD check the data for printable characters. implementations SHOULD check the data for printable characters.
An implementation MUST NOT assume the Peer Type field is NUL- An implementation MUST NOT assume the Peer Type field is NUL-
terminated. terminated.
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | IPv4 Attached Subnet : | Flags | IPv4 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: ...cont. |Prefix Length | : ...cont. |Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 10 Data Item Type: 10
Length: 6 Length: 6
Flags: Flags field, defined below. Flags: Flags field, defined below.
IPv4 Subnet: The IPv4 subnet reachable at the destination. IPv4 Subnet: The IPv4 subnet reachable at the destination.
Prefix Length: Length of the prefix (1-32) for the IPv4 subnet. A Prefix Length: Length of the prefix (0-32) 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
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
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| Flags | IPv6 Attached Subnet : | Flags | IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Attached Subnet : : IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Attached Subnet : : IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv6 Attached Subnet : : IPv6 Attached Subnet :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: ...cont. | Prefix Len. | : ...cont. | Prefix Len. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 11 Data Item Type: 11
Length: 18 Length: 18
Flags: Flags field, defined below. Flags: Flags field, defined below.
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 (0-128) 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
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Reserved |A| | Reserved |A|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 Data Rate (Receive) and
rates, current data rate receive MUST be set equal to the maximum Maximum Data Rate (Receive) (Section 10.12), Current Data Rate
data rate receive. (Receive) MUST be set equal to the Maximum Data Rate (Receive). The
Current Data Rate (Receive) MUST NOT exceed the Maximum Data Rate
(Receive).
10.15. Current Data Rate (Transmit) 10.15. Current Data Rate (Transmit)
The Current Data Rate (Transmit) (CDRT) Data Item is used to indicate The Current Data Rate (Transmit) (CDRT) Data Item is used to indicate
the rate at which the link is currently operating for transmitting the rate at which the link is currently operating for transmitting
traffic. traffic.
When used in the Link Characteristics Request Message (Section 9.18), When used in the Link Characteristics Request Message (Section 9.18),
Current Data Rate (Transmit) represents the desired transmit rate, in Current Data Rate (Transmit) represents the desired transmit rate, in
bits per second, on the link. bits per second, on the link.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Item Type: 15 Data Item Type: 15
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 Data Rate (Transmit) and
rates, current data rate transmit MUST be set equal to the maximum Maximum Data Rate (Transmit) (Section 10.13), Current Data Rate
data rate transmit. (Transmit) MUST be set equal to the Maximum Data Rate (Transmit).
The Current Data Rate (Transmit) MUST NOT exceed the Maximum Data
Rate (Transmit).
10.16. Latency 10.16. Latency
The Latency Data Item is used to indicate the amount of latency, in The Latency Data Item is used to indicate the amount of latency, in
microseconds, on the link. microseconds, on the link.
The Latency value is reported as transmission delay. The calculation The Latency value is reported as transmission delay. The calculation
of latency is implementation dependent. For example, the latency may of latency is implementation dependent. For example, the latency may
be a running average calculated from the internal queuing. be a running average calculated from the internal queuing.
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+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Data Item Type: 17 Data Item Type: 17
Length: 1 Length: 1
Resources: An 8-bit unsigned integer percentage, 0-100, representing Resources: An 8-bit unsigned integer percentage, 0-100, representing
the amount of resources available. Any value greater than 100 the amount of resources available. Any value greater than 100
MUST be considered as invalid. MUST be considered as invalid.
If a device cannot calculate Resources, this Data Item SHOULD NOT be If a device cannot calculate Resources, this Data Item MUST NOT be
issued. issued.
10.18. Relative Link Quality (Receive) 10.18. Relative Link Quality (Receive)
The Relative Link Quality (Receive) (RLQR) Data Item is used to The Relative Link Quality (Receive) (RLQR) Data Item is used to
indicate the quality of the link to a destination for receiving indicate the quality of the link to a destination for receiving
traffic as a percentage, with 0 meaning 'worst quality', and 100 traffic, with 0 meaning 'worst quality', and 100 meaning 'best
meaning 'best quality'. quality'.
Quality in this context is defined as an indication of the stability Quality in this context is defined as an indication of the stability
of a link for reception; a destination with high Relative Link of a link for reception; a destination with high Relative Link
Quality (Receive) is expected to have generally stable DLEP metrics, Quality (Receive) is expected to have generally stable DLEP metrics,
and the metrics of a destination with low Relative Link Quality and the metrics of a destination with low Relative Link Quality
(Receive) can be expected to rapidly fluctuate over a wide range. (Receive) can be expected to rapidly fluctuate over a wide range.
The Relative Link Quality (Receive) Data Item contains the following The Relative Link Quality (Receive) Data Item contains the following
fields: fields:
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Data Item Type: 18 Data Item Type: 18
Length: 1 Length: 1
Relative Link Quality (Receive): A non-dimensional unsigned 8-bit Relative Link Quality (Receive): A non-dimensional unsigned 8-bit
integer, 0-100, representing relative quality of the link for integer, 0-100, representing relative quality of the link for
receiving traffic. Any value greater than 100 MUST be considered receiving traffic. Any value greater than 100 MUST be considered
as invalid. as invalid.
If a device cannot calculate the Relative Link Quality (Receive), If a device cannot calculate the Relative Link Quality (Receive),
this Data Item SHOULD NOT be issued. this Data Item MUST NOT be issued.
10.19. Relative Link Quality (Transmit) 10.19. Relative Link Quality (Transmit)
The Relative Link Quality (Transmit) (RLQT) Data Item is used to The Relative Link Quality (Transmit) (RLQT) Data Item is used to
indicate the quality of the link to a destination for transmitting indicate the quality of the link to a destination for transmitting
traffic as a percentage, with 0 meaning 'worst quality', and 100 traffic, with 0 meaning 'worst quality', and 100 meaning 'best
meaning 'best quality'. quality'.
Quality in this context is defined as an indication of the stability Quality in this context is defined as an indication of the stability
of a link for transmission; a destination with high Relative Link of a link for transmission; a destination with high Relative Link
Quality (Transmit) is expected to have generally stable DLEP metrics, Quality (Transmit) is expected to have generally stable DLEP metrics,
and the metrics of a destination with low Relative Link Quality and the metrics of a destination with low Relative Link Quality
(Transmit) can be expected to rapidly fluctuate over a wide range. (Transmit) can be expected to rapidly fluctuate over a wide range.
The Relative Link Quality (Transmit) Data Item contains the following The Relative Link Quality (Transmit) Data Item contains the following
fields: fields:
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Data Item Type: 19 Data Item Type: 19
Length: 1 Length: 1
Relative Link Quality (Transmit): A non-dimensional unsigned 8-bit Relative Link Quality (Transmit): A non-dimensional unsigned 8-bit
integer, 0-100, representing relative quality of the link for integer, 0-100, representing relative quality of the link for
transmitting traffic. Any value greater than 100 MUST be transmitting traffic. Any value greater than 100 MUST be
considered as invalid. considered as invalid.
If a device cannot calculate the Relative Link Quality (Transmit), If a device cannot calculate the Relative Link Quality (Transmit),
this Data Item SHOULD NOT be issued. this Data Item MUST NOT be issued.
10.20. Maximum Transmission Unit (MTU) 10.20. Maximum Transmission Unit (MTU)
The Maximum Transmission Unit (MTU) Data Item is used to indicate the The Maximum Transmission Unit (MTU) Data Item is used to indicate the
maximum size, in octets, of an IP packet that can be transmitted maximum size, in octets, of an IP packet that can be transmitted
without fragmentation, including headers, but excluding any lower without fragmentation, including headers, but excluding any lower
layer headers. layer headers.
The Maximum Transmission Unit Data Item contains the following The Maximum Transmission Unit Data Item contains the following
fields: fields:
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Data Item Type: 20 Data Item Type: 20
Length: 2 Length: 2
Maximum Transmission Unit: The maximum size, in octets, of an IP Maximum Transmission Unit: The maximum size, in octets, of an IP
packet that can be transmitted without fragmentation, including packet that can be transmitted without fragmentation, including
headers, but excluding any lower layer headers. headers, but excluding any lower layer headers.
If a device cannot calculate the Maximum Transmission Unit, this Data If a device cannot calculate the Maximum Transmission Unit, this Data
Item SHOULD NOT be issued. Item MUST NOT be issued.
11. Security Considerations 11. Security Considerations
The potential security concerns when using DLEP are: The potential security concerns when using DLEP are:
1. An attacker might pretend to be a DLEP peer, either at DLEP 1. An attacker might pretend to be a DLEP participant, either at
session initialization, or by injection of DLEP Messages once a DLEP session initialization, or by injection of DLEP Messages
session has been established, and/or once a session has been established, and/or
2. DLEP Data Items could be altered by an attacker, causing the 2. DLEP Data Items could be altered by an attacker, causing the
receiving implementation to inappropriately alter its information receiving implementation to inappropriately alter its information
base concerning network status. base concerning network status.
Since DLEP is restricted to operation over a single (possibly Since DLEP is restricted to operation over a single (possibly
logical) hop at layer 2, implementations requiring authentication and logical) hop at layer 2, implementations requiring authentication and
/or encryption of traffic MUST take steps to secure the Layer 2 link. /or encryption of traffic MUST take steps to secure the Layer 2 link.
Examples of technologies that can be deployed to secure the Layer 2 Examples of technologies that can be deployed to secure the Layer 2
link include [IEEE-802.1AE] and [IEEE-802.1X]. link include [IEEE-802.1AE] and [IEEE-802.1X].
skipping to change at page 52, line 15 skipping to change at page 52, line 15
This specification does not address security of the data plane, as it This specification does not address security of the data plane, as it
(the data plane) is not affected, and standard security procedures (the data plane) is not affected, and standard security procedures
can be employed. can be employed.
12. IANA Considerations 12. IANA Considerations
This section specifies requests to IANA. This section specifies requests to IANA.
12.1. Registrations 12.1. Registrations
This specification defines: Upon approval of this document, IANA is requested to create a new
protocol registry for Dynamic Link Event Protocol (DLEP). The
o A new repository for DLEP Signals, with three (3) values currently remainder of this section requests the creation of new DLEP specific
assigned. registries.
o Reservation of a Private Use numbering space within the above
repository for experimental DLEP Signals.
o A new repository for DLEP Messages, with seventeen (17) values
currently assigned.
o Reservation of a Private Use numbering space within the above
repository for experimental DLEP Messages.
o A new repository for DLEP Data Items, with twenty one (21) values
currently assigned.
o Reservation of a Private Use numbering space within the Data Items
repository for experimental Data Items.
o A new repository for DLEP status codes, with eight (8) currently
assigned.
o Reservation of a Private Use numbering space within the status
codes repository for experimental status codes.
o A new repository for DLEP extensions, with one (1) value currently
assigned.
o Reservation of a Private Use numbering space within the extension
repository for experimental extensions.
o A request for allocation of a well-known port for DLEP TCP and UDP
communication.
o A request for allocation of a link-local multicast IPv4 address
for DLEP discovery.
o A request for allocation of a link-local multicast IPv6 address
for DLEP discovery.
12.2. Signal Type Registration 12.2. Signal Type Registration
A new repository must be created with the values of the DLEP Signals, Upon approval of this document, IANA is requested to create a new
entitled "Signal Type Values for the Dynamic Link Event Protocol DLEP registry, named "Signal Type Values".
(DLEP)". The repository is to be managed using the "Specification
Required" policy documented in [RFC5226].
All Signal values are in the range [0..65535], defined in Table 1. The following table provides initial registry values and the
[RFC5226] defined policies that should apply to the registry:
+--------------+-------------------------+
| Type Code | Description/Policy |
+--------------+-------------------------+
| 0 | Reserved |
| 1 | Peer Discovery Signal |
| 2 | Peer Offer Signal |
| 3-65519 | Specification Required |
| 65520-65534 | Private Use |
| 65535 | Reserved |
+--------------+-------------------------+
12.3. Message Type Registration 12.3. Message Type Registration
A new repository must be created with the values of the DLEP Upon approval of this document, IANA is requested to create a new
Messages, entitled "Message Type Values for the Dynamic Link Event DLEP registry, named "Message Type Values".
Protocol (DLEP)". The repository is to be managed using the
"Specification Required" policy documented in [RFC5226].
All Message values are in the range [0..65535], defined in Table 2. The following table provides initial registry values and the
[RFC5226] defined policies that should apply to the registry:
+--------------+------------------------------------------+
| Type Code | Description/Policy |
+--------------+------------------------------------------+
| 0 | Reserved |
| 1 | Session Initialization Message |
| 2 | Session Initialization Response Message |
| 3 | Session Update Message |
| 4 | Session Update Response Message |
| 5 | Session Termination Message |
| 6 | Session Termination Response Message |
| 7 | Destination Up Message |
| 8 | Destination Up Response Message |
| 9 | Destination Announce Message |
| 10 | Destination Announce Response Message |
| 11 | Destination Down Message |
| 12 | Destination Down Response Message |
| 13 | Destination Update Message |
| 14 | Link Characteristics Request Message |
| 15 | Link Characteristics Response Message |
| 16 | Heartbeat Message |
| 17-65519 | Specification Required |
| 65520-65534 | Private Use |
| 65535 | Reserved |
+--------------+------------------------------------------+
12.4. DLEP Data Item Registrations 12.4. DLEP Data Item Registrations
A new repository for DLEP Data Items must be created, entitled "Data Upon approval of this document, IANA is requested to create a new
Item Type Values for the Dynamic Link Event Protocol (DLEP)". The DLEP registry, named "Data Item Values".
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 3. The following table provides initial registry values and the
[RFC5226] defined policies that should apply to the registry:
+--------------+------------------------------------------+
| Type Code | Description/Policy |
+--------------+------------------------------------------+
| 0 | Reserved |
| 1 | Status |
| 2 | IPv4 Connection Point |
| 3 | IPv6 Connection Point |
| 4 | Peer Type |
| 5 | Heartbeat Interval |
| 6 | Extensions Supported |
| 7 | MAC Address |
| 8 | IPv4 Address |
| 9 | IPv6 Address |
| 10 | IPv4 Attached Subnet |
| 11 | IPv6 Attached Subnet |
| 12 | Maximum Data Rate (Receive) (MDRR) |
| 13 | Maximum Data Rate (Transmit) (MDRT) |
| 14 | Current Data Rate (Receive) (CDRR) |
| 15 | Current Data Rate (Transmit) (CDRT) |
| 16 | Latency |
| 17 | Resources (RES) |
| 18 | Relative Link Quality (Receive) (RLQR) |
| 19 | Relative Link Quality (Transmit) (RLQT) |
| 20 | Maximum Transmission Unit (MTU) |
| 21-65407 | Specification Required |
| 65408-65534 | Private Use |
| 65535 | Reserved |
+--------------+------------------------------------------+
12.5. DLEP Status Code Registrations 12.5. DLEP Status Code Registrations
A new repository for DLEP status codes must be created, entitled Upon approval of this document, IANA is requested to create a new
"Status Code Values for the Dynamic Link Event Protocol (DLEP)". The DLEP registry, named "Status Code Values".
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 4. The following table provides initial registry values and the
[RFC5226] defined policies that should apply to the registry:
With the exception of the reserved value 255, all status codes with +--------------+---------------+-------------------------+
values >= 100 are marked as 'Continue' codes, others 'Terminate'. | Status Code | Failure Mode | Description/Policy |
+--------------+---------------+-------------------------+
| 0 | Continue | Success |
| 1 | Continue | Not Interested |
| 2 | Continue | Request Denied |
| 3-111 | Continue | Specification Required |
| 112-127 | Continue | Private Use |
| 128 | Terminate | Unknown Message |
| 129 | Terminate | Unexpected Message |
| 130 | Terminate | Invalid Data |
| 131 | Terminate | Invalid Destination |
| 132 | Terminate | Timed Out |
| 132-239 | Terminate | Specification Required |
| 240-254 | Terminate | Private Use |
| 255 | Terminate | Reserved |
+--------------+---------------+-------------------------+
12.6. DLEP Extensions Registrations 12.6. DLEP Extensions Registrations
A new repository for DLEP extensions must be created, entitled Upon approval of this document, IANA is requested to create a new
"Extension Type Values for the Dynamic Link Event Protocol (DLEP)". DLEP registry, named "Extension Type Values".
The repository is to be managed using the "Specification Required"
policy documented in [RFC5226].
All extension values are in the range [0..65535]. Current The following table provides initial registry values and the
allocations are: [RFC5226] defined policies that should apply to the registry:
+--------------+----------------------------------------------+ +--------------+----------------------------+
| Code | Description | | Code | Description/Policy |
+--------------+----------------------------------------------+ +--------------+----------------------------+
| 0 | Reserved | | 0 | Reserved |
| 1 | Credit Windowing | | 1 | Credit Windowing [CREDIT] |
| 2-65519 | Unassigned. Available for future extensions | | 2-65519 | Specification Required |
| 65520-65534 | Private Use. Available for experiments | | 65520-65534 | Private Use |
| 65535 | Reserved | | 65535 | Reserved |
+--------------+----------------------------------------------+ +--------------+----------------------------+
Table 5: DLEP Extension types Table 5: DLEP Extension types
12.7. DLEP Well-known Port 12.7. DLEP Well-known Port
It is requested that IANA allocate a single well-known port number Upon approval of this document, IANA is requested to assign a single
for both TCP and UDP, for DLEP communication. SCTP port allocation value in the "Service Name and Transport Protocol Port Number
is not required. Registry" found at https://www.iana.org/assignments/service-names-
port-numbers/service-names-port-numbers.xhtml for use by "DLEP", as
defined in this document. This assignment should be valid for TCP
and UDP. SCTP port allocation is not required.
12.8. DLEP IPv4 Link-local Multicast Address 12.8. DLEP IPv4 Link-local Multicast Address
It is requested that IANA allocate an IPv4 link-local multicast Upon approval of this document, IANA is requested to assign a IPv4
address for DLEP discovery Signals. multicast address registry found at http://www.iana.org/assignments/
multicast-addresses for use as the "IPv4 DLEP Discovery Address".
12.9. DLEP IPv6 Link-local Multicast Address 12.9. DLEP IPv6 Link-local Multicast Address
It is requested that IANA allocate an IPv6 link-local multicast Upon approval of this document, IANA is requested to assign a IPv6
address for DLEP discovery Signals. multicast address registry found at http://www.iana.org/assignments/
multicast-addresses for use as the "IPv6 DLEP Discovery Address".
13. Acknowledgements 13. Acknowledgements
We would like to acknowledge and thank the members of the DLEP design We would like to acknowledge and thank the members of the DLEP design
team, who have provided invaluable insight. The members of the team, who have provided invaluable insight. The members of the
design team are: Teco Boot, Bow-Nan Cheng, John Dowdell, and Henning design team are: Teco Boot, Bow-Nan Cheng, John Dowdell, and Henning
Rogge. Rogge.
We would also like to acknowledge the influence and contributions of We would also like to acknowledge the influence and contributions of
Greg Harrison, Chris Olsen, Martin Duke, Subir Das, Jaewon Kang, Greg Harrison, Chris Olsen, Martin Duke, Subir Das, Jaewon Kang,
skipping to change at page 55, line 44 skipping to change at page 56, line 44
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---->X Signal.
~ ~ ~ ~ ~ ~ ~ Router discovery timer expires ~ ~ ~ ~ ~ ~ ~ Router discovery timer expires
without receiving Peer Offer. without receiving Peer Offer.
| Router sends another Peer | Router sends another Peer
|-------Peer Discovery---------->| Discovery Signal. |-------Peer Discovery---------->| Discovery Signal.
| |
| Modem receives Peer Discovery | Modem receives Peer Discovery
| Signal. | Signal.
| |
skipping to change at page 56, line 22 skipping to change at page 57, line 22
Appendix B. Peer Level Message Flows Appendix B. Peer Level Message Flows
B.1. Session Initialization B.1. Session Initialization
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
| Router connects to discovered or | Router connects to discovered or
| pre-configured Modem Connection | pre-configured Modem Connection
|---------TCP connect----------> Point. |--TCP connection established---> Point.
| |
| Router sends Session | Router sends Session
|----Session Initialization----->| Initialization Message. |----Session Initialization----->| Initialization Message.
| |
| Modem receives Session | Modem receives Session
| Initialization Message. | Initialization Message.
| |
| Modem sends Session Initialization | Modem sends Session Initialization
|<--Session Initialization Resp.-| Response, with Success Status Data |<--Session Initialization Resp.-| Response, with Success Status Data
| | Item. | | Item.
skipping to change at page 56, line 44 skipping to change at page 57, line 44
|<<============================>>| Session established. Heartbeats |<<============================>>| Session established. Heartbeats
: : begin. : : begin.
B.2. Session Initialization - Refused B.2. Session Initialization - Refused
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
| Router connects to discovered or | Router connects to discovered or
| pre-configured Modem Connection | pre-configured Modem Connection
|---------TCP connect----------> Point. |--TCP connection established---> Point.
| |
| Router sends Session | Router sends Session
|-----Session Initialization---->| Initialization Message. |-----Session Initialization---->| Initialization Message.
| |
| Modem receives Session | Modem receives Session
| Initialization Message, and will | Initialization Message, and will
| not support the advertised | not support the advertised
| extensions. | extensions.
| |
| Modem sends Session Initialization | Modem sends Session Initialization
skipping to change at page 59, line 37 skipping to change at page 60, line 37
| Message from the Modem. | Message from the Modem.
| |
| Modem resets heartbeats missed | Modem resets heartbeats missed
| counter. | counter.
B.8. Router Detects a Heartbeat timeout B.8. Router Detects a Heartbeat timeout
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
||<----------------------| Router misses a heartbeat X<----------------------| Router misses a heartbeat
| ||<----------------------| Router misses too many heartbeats | X<----------------------| 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...
B.9. Modem Detects a Heartbeat timeout B.9. Modem Detects a Heartbeat timeout
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
|---------------------->|| Modem misses a heartbeat |---------------------->X Modem misses a heartbeat
|---------------------->|| | Modem misses too many heartbeats |---------------------->X | 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...
Appendix C. Destination Specific Message Flows Appendix C. Destination Specific Message Flows
C.1. Common Destination Notification C.1. Common Destination Notification
Router Modem Message Description Router Modem Message Description
======================================================================== ========================================================================
| Modem detects a new logical | Modem detects a new logical
| destination is reachable, and | destination is reachable, and
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