draft-ietf-lsvr-l3dl-00.txt   draft-ietf-lsvr-l3dl-01.txt 
Network Working Group R. Bush Network Working Group R. Bush
Internet-Draft Arrcus & IIJ Internet-Draft Arrcus & IIJ
Intended status: Standards Track R. Austein Intended status: Standards Track R. Austein
Expires: October 25, 2019 K. Patel Expires: December 14, 2019 K. Patel
Arrcus Arrcus
April 23, 2019 June 12, 2019
Layer 3 Discovery and Liveness Layer 3 Discovery and Liveness
draft-ietf-lsvr-l3dl-00 draft-ietf-lsvr-l3dl-01
Abstract Abstract
In Massive Data Centers (MDCs), BGP-SPF and similar routing protocols In Massive Data Centers (MDCs), BGP-SPF and similar routing protocols
are used to build topology and reachability databases. These are used to build topology and reachability databases. These
protocols need to discover IP Layer 3 attributes of links, such as protocols need to discover IP Layer 3 attributes of links, such as
logical link IP encapsulation abilities, IP neighbor address logical link IP encapsulation abilities, IP neighbor address
discovery, and link liveness. The Layer 3 Discovery and Liveness discovery, and link liveness. The Layer 3 Discovery and Liveness
protocol specified in this document collects these data, which are protocol specified in this document collects these data, which are
then disseminated using BGP-SPF and similar protocols. then disseminated using BGP-SPF and similar protocols.
skipping to change at page 1, line 46 skipping to change at page 1, line 46
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
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 October 25, 2019. This Internet-Draft will expire on December 14, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 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
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 30 skipping to change at page 2, line 30
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Background . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Top Level Overview . . . . . . . . . . . . . . . . . . . . . 5 4. Top Level Overview . . . . . . . . . . . . . . . . . . . . . 5
5. Inter-Link Protocol Overview . . . . . . . . . . . . . . . . 6 5. Inter-Link Protocol Overview . . . . . . . . . . . . . . . . 6
5.1. L3DL Ladder Diagram . . . . . . . . . . . . . . . . . . . 7 5.1. L3DL Ladder Diagram . . . . . . . . . . . . . . . . . . . 7
6. Transport Layer . . . . . . . . . . . . . . . . . . . . . . . 8 6. Transport Layer . . . . . . . . . . . . . . . . . . . . . . . 8
7. The Checksum . . . . . . . . . . . . . . . . . . . . . . . . 9 7. The Checksum . . . . . . . . . . . . . . . . . . . . . . . . 9
8. TLV PDUs . . . . . . . . . . . . . . . . . . . . . . . . . . 11 8. TLV PDUs . . . . . . . . . . . . . . . . . . . . . . . . . . 12
9. Logical Link Endpoint Identifier . . . . . . . . . . . . . . 12 9. Logical Link Endpoint Identifier . . . . . . . . . . . . . . 13
10. HELLO . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 10. HELLO . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
11. OPEN . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 11. OPEN . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
12. ACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 12. ACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
12.1. Retransmission . . . . . . . . . . . . . . . . . . . . . 17 12.1. Retransmission . . . . . . . . . . . . . . . . . . . . . 18
13. The Encapsulations . . . . . . . . . . . . . . . . . . . . . 17 13. The Encapsulations . . . . . . . . . . . . . . . . . . . . . 18
13.1. The Encapsulation PDU Skeleton . . . . . . . . . . . . . 18 13.1. The Encapsulation PDU Skeleton . . . . . . . . . . . . . 19
13.2. Prim/Loop Flags . . . . . . . . . . . . . . . . . . . . 19 13.2. Encapsulaion Flags . . . . . . . . . . . . . . . . . . . 20
13.3. IPv4 Encapsulation . . . . . . . . . . . . . . . . . . . 19 13.3. IPv4 Encapsulation . . . . . . . . . . . . . . . . . . . 21
13.4. IPv6 Encapsulation . . . . . . . . . . . . . . . . . . . 20 13.4. IPv6 Encapsulation . . . . . . . . . . . . . . . . . . . 21
13.5. MPLS Label List . . . . . . . . . . . . . . . . . . . . 20 13.5. MPLS Label List . . . . . . . . . . . . . . . . . . . . 22
13.6. MPLS IPv4 Encapsulation . . . . . . . . . . . . . . . . 21 13.6. MPLS IPv4 Encapsulation . . . . . . . . . . . . . . . . 22
13.7. MPLS IPv6 Encapsulation . . . . . . . . . . . . . . . . 21 13.7. MPLS IPv6 Encapsulation . . . . . . . . . . . . . . . . 23
14. KEEPALIVE - Layer 2 Liveness . . . . . . . . . . . . . . . . 22 14. VENDOR - Vendor Extensions . . . . . . . . . . . . . . . . . 24
15. VENDOR - Vendor Extensions . . . . . . . . . . . . . . . . . 23 15. KEEPALIVE - Layer 2 Liveness . . . . . . . . . . . . . . . . 25
16. Layers 2.5 and 3 Liveness . . . . . . . . . . . . . . . . . . 23 16. Layers 2.5 and 3 Liveness . . . . . . . . . . . . . . . . . . 25
17. The North/South Protocol . . . . . . . . . . . . . . . . . . 24 17. The North/South Protocol . . . . . . . . . . . . . . . . . . 26
17.1. Use BGP-LS as Much as Possible . . . . . . . . . . . . . 24 17.1. Use BGP-LS as Much as Possible . . . . . . . . . . . . . 26
17.2. Extensions to BGP-LS . . . . . . . . . . . . . . . . . . 24 17.2. Extensions to BGP-LS . . . . . . . . . . . . . . . . . . 26
18. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 25 18. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 27
18.1. HELLO Discussion . . . . . . . . . . . . . . . . . . . . 25 18.1. HELLO Discussion . . . . . . . . . . . . . . . . . . . . 27
18.2. HELLO versus KEEPALIVE . . . . . . . . . . . . . . . . . 25 18.2. HELLO versus KEEPALIVE . . . . . . . . . . . . . . . . . 27
19. VLANs/SVIs/Sub-interfaces . . . . . . . . . . . . . . . . . . 25 19. VLANs/SVIs/Sub-interfaces . . . . . . . . . . . . . . . . . . 27
20. Implementation Considerations . . . . . . . . . . . . . . . . 25 20. Implementation Considerations . . . . . . . . . . . . . . . . 27
21. Security Considerations . . . . . . . . . . . . . . . . . . . 26 21. Security Considerations . . . . . . . . . . . . . . . . . . . 28
22. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26 22. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29
23. IEEE Considerations . . . . . . . . . . . . . . . . . . . . . 28 22.1. PDU Types . . . . . . . . . . . . . . . . . . . . . . . 29
24. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 28 22.2. Signature Type . . . . . . . . . . . . . . . . . . . . . 29
25. References . . . . . . . . . . . . . . . . . . . . . . . . . 28 22.3. Flag Bits . . . . . . . . . . . . . . . . . . . . . . . 29
25.1. Normative References . . . . . . . . . . . . . . . . . . 28 22.4. Error Codes . . . . . . . . . . . . . . . . . . . . . . 30
25.2. Informative References . . . . . . . . . . . . . . . . . 30 23. IEEE Considerations . . . . . . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31 24. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 30
25. References . . . . . . . . . . . . . . . . . . . . . . . . . 30
25.1. Normative References . . . . . . . . . . . . . . . . . . 30
25.2. Informative References . . . . . . . . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 33
1. Introduction 1. Introduction
The Massive Data Center (MDC) environment presents unusual problems The Massive Data Center (MDC) environment presents unusual problems
of scale, e.g. O(10,000) devices, while its homogeneity presents of scale, e.g. O(10,000) devices, while its homogeneity presents
opportunities for simple approaches. Approaches such as Jupiter opportunities for simple approaches. Approaches such as Jupiter
Rising [JUPITER] use a central controller to deal with scaling, while Rising [JUPITER] use a central controller to deal with scaling, while
BGP-SPF [I-D.ietf-lsvr-bgp-spf] provides massive scale-out without BGP-SPF [I-D.ietf-lsvr-bgp-spf] provides massive scale-out without
centralization using a tried and tested scalable distributed control centralization using a tried and tested scalable distributed control
plane, offering a scalable routing solution in Clos [Clos0][Clos1] plane, offering a scalable routing solution in Clos [Clos0][Clos1]
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used by all widely deployed Layer 2 network technologies used by all widely deployed Layer 2 network technologies
of interest, especially Ethernet. See [IEEE.802_2001]. of interest, especially Ethernet. See [IEEE.802_2001].
MDC: Massive Data Center, commonly thousands of TORs. MDC: Massive Data Center, commonly thousands of TORs.
MTU: Maximum Transmission Unit, the size in octets of the MTU: Maximum Transmission Unit, the size in octets of the
largest packet that can be sent on a medium, see [RFC1122] largest packet that can be sent on a medium, see [RFC1122]
1.3.3. 1.3.3.
PDU: Protocol Data Unit, an L3DL application layer message. A PDU: Protocol Data Unit, an L3DL application layer message. A
PDU may need to be broken into multiple Datagrams to make PDU may need to be broken into multiple Datagrams to make
it through MTU or other restrictions. it through MTU or other restrictions.
RouterID: An 32-bit identifier unique in the current routing domain, RouterID: An 32-bit identifier unique in the current routing domain,
see [RFC4271] updated by [RFC6286]. see [RFC6286].
Session: An established, via OPEN PDUs, session between two L3DL Session: An established, via OPEN PDUs, session between two L3DL
capable link end-points, capable link end-points,
SPF: Shortest Path First, an algorithm for finding the shortest SPF: Shortest Path First, an algorithm for finding the shortest
paths between nodes in a graph; AKA Dijkstra's algorithm. paths between nodes in a graph; AKA Dijkstra's algorithm.
System Identifier: An eight octet ISO System Identifier a la System Identifier: An eight octet ISO System Identifier a la
[RFC1629] System ID [RFC1629] System ID
TOR: Top Of Rack switch, aggregates the servers in a rack and TOR: Top Of Rack switch, aggregates the servers in a rack and
connects to aggregation layers of the Clos tree, AKA the connects to aggregation layers of the Clos tree, AKA the
Clos spine. Clos spine.
ZTP: Zero Touch Provisioning gives devices initial addresses, ZTP: Zero Touch Provisioning gives devices initial addresses,
credentials, etc. on boot/restart. credentials, etc. on boot/restart.
3. Background 3. Background
L3DL assumes a Clos type datacenter scale and topology, but can L3DL is primarily designed for a Clos type datacenter scale and
accommodate richer topologies which contain potential cycles. topology, but can accommodate richer topologies which contain
potential cycles.
While L3DL is designed for the MDC, there are no inherent reasons it While L3DL is designed for the MDC, there are no inherent reasons it
could not run on a WAN. The authentication and authorization needed could not run on a WAN. The authentication and authorization needed
to run safely on a WAN need to be considered, and the appropriate to run safely on a WAN need to be considered, and the appropriate
level of security options chosen. level of security options chosen.
L3DL assumes a new IEEE assigned EtherType (TBD). L3DL assumes a new IEEE assigned EtherType (TBD).
The number of addresses of the Encapsulations on a link may be fairly The number of addresses of one Encapsulation type on an interface
large given a TOR with more than 20 servers, each server possibly link may be quite large given a TOR with tens of servers, each server
having on the order of a hundred micro-services resulting in an having a few hundred micro-services, resulting in an inordinate
inordinate number of addresses. And security will further add to the number of addresses. And highly automated micro-service migration
length of PDUs. PDUs with lengths over 10,000 octets are likely or can cause serious address prefix disaggregation, resulting in
quite possible. interfaces with thousands of disaggregated prefixes.
Therefore the L3DL protocol is session oriented and uses incremental
announcement and widrawal with hot restart, a la BGP ([RFC4271]).
4. Top Level Overview 4. Top Level Overview
o Devices discover each other on logical links o Devices discover each other on logical links
o Logical Link Endpoint Identifiers are exchanged o Logical Link Endpoint Identifiers are exchanged
o Layer 2 Liveness Checks may be started o Layer 2 Liveness Checks may be started
o Encapsulation data are exchanged and IP-Level Liveness Checks o Encapsulation data are exchanged and IP-Level Liveness Checks
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The upper layer BGP family routing protocols cross all the devices, The upper layer BGP family routing protocols cross all the devices,
though they are not part of these L3DL protocols. though they are not part of these L3DL protocols.
To simplify this document, Layer 2 framing is not shown. L3DL is To simplify this document, Layer 2 framing is not shown. L3DL is
about layer 3. about layer 3.
5. Inter-Link Protocol Overview 5. Inter-Link Protocol Overview
Two devices discover each other and their respective identities by Two devices discover each other and their respective identities by
sending multicast HELLO PDUs (Section 10). To allow discovery of new sending multicast HELLO PDUs (Section 10). To allow discovery of new
devices coming up on a multi-link topology, devices send periodic devices coming up on a multi-link topology, devices on such a
HELLOs forever, see Section 18.1. topology send periodic HELLOs forever, see Section 18.1.
Once a new device is recognized, both devices attempt to negotiate Once a new device is recognized, both devices attempt to negotiate
and establish peering by sending unicast OPEN PDUs (Section 11). In and establish peering by sending unicast OPEN PDUs (Section 11). In
an established peering, Encapsulations (Section 13) may be announced an established peering, the Encapsulations (Section 13) configured on
and modified. When two devices on a link have compatible an end point may be announced and modified. Note that these are only
Encapsulations and addresses, i.e. the same AFI/SAFI and the same the encapsuation and addresses on the announcing interface; though a
subnet, the link is announced via the BGP-LS API. device's loopback interface(s) may also be announced. When two
devices on a link have compatible Encapsulations and addresses, i.e.
the same AFI/SAFI and the same subnet, the link is announced via the
BGP-LS API.
5.1. L3DL Ladder Diagram 5.1. L3DL Ladder Diagram
The HELLO, Section 10, is a priming message. It is a small L3DL PDU The HELLO, Section 10, is a priming message. It is a small L3DL PDU
encapsulated in an Ethernet multicast frame with the simple goal of encapsulated in an Ethernet multicast frame with the simple goal of
discovering the identities of logical link endpoint(s) reachable from discovering the identities of logical link endpoint(s) reachable from
a Logical Link Endpoint, Section 9. a Logical Link Endpoint, Section 9.
The HELLO and OPEN, Section 11, PDUs, which are used to discover and The HELLO and OPEN, Section 11, PDUs, which are used to discover and
exchange detailed Logical Link Endpoint Identifiers, LLEIs, and the exchange detailed Logical Link Endpoint Identifiers, LLEIs, and the
ACK/ERROR PDU, are mandatory; other PDUs are optional; though at ACK/ERROR PDU, are mandatory; other PDUs are optional; though at
least one encapsulation MUST be agreed at some point. least one encapsulation SHOULD be agreed at some point.
The following is a ladder-style sketch of the L3DL protocol The following is a ladder-style sketch of the L3DL protocol
exchanges: exchanges:
| HELLO | Logical Link Peer discovery | HELLO | Logical Link Peer discovery
|---------------------------->| |---------------------------->|
| HELLO | Mandatory | HELLO | Mandatory
|<----------------------------| |<----------------------------|
| | | |
| | | |
| OPEN | MACs, IDs, and Capabilities | OPEN | MACs, IDs, etc.
|---------------------------->| |---------------------------->|
| ACK |
|<----------------------------|
| |
| OPEN | Mandatory | OPEN | Mandatory
|<----------------------------| |<----------------------------|
| ACK |
|---------------------------->|
| | | |
| | | |
| Interface IPv4 Addresses | Interface IPv4 Addresses | Interface IPv4 Addresses | Interface IPv4 Addresses
|---------------------------->| Optional |---------------------------->| Optional
| ACK | | ACK |
|<----------------------------| |<----------------------------|
| | | |
| Interface IPv4 Addresses | | Interface IPv4 Addresses |
|<----------------------------| |<----------------------------|
| ACK | | ACK |
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| | | |
| | | |
| L3DL KEEPALIVE | Layer 2 Liveness | L3DL KEEPALIVE | Layer 2 Liveness
|---------------------------->| Optional |---------------------------->| Optional
| L3DL KEEPALIVE | | L3DL KEEPALIVE |
|<----------------------------| |<----------------------------|
6. Transport Layer 6. Transport Layer
L3DL PDUs are carried by a simple transport layer which allows long L3DL PDUs are carried by a simple transport layer which allows long
PDUs to occupy many Ethernet frames. The L3DL data in each frame is PDUs to occupy many Ethernet frames. An L3DL frame is referred to as
referred to as a Datagram. a Datagram.
The L3DL Transport Layer encapsulates each Datagram using a common The L3DL Transport Layer encapsulates each Datagram using a common
transport header. transport header.
If a PDU does not fit in a single datagram, it is broken into If a PDU does not fit in a single datagram, it is broken into
multiple datagrams and reassembled by the receiver a la [RFC0791]. multiple datagrams and reassembled by the receiver a la [RFC0791]
Section 2.3 Fragmentation.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version |L|Datagram Num.| Datagram Length | | Version |L| Datagram Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Checksum | | Datagram Length | Checksum ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ | Payload... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The fields of the L3DL Transport Header are as follows: The fields of the L3DL Transport Header are as follows:
Version: Version number of the protocol, currently 0. Values other Version: Seven-bit Version number of the protocol, currently 0.
than 0 are treated as errors. Values other than 0 are treated as errors. The protocol version
nees to be in one and only one place, so it is in the datagram as
opposed to, for example, the PDU header.
L: A bit that set to one if this Datagram is the last Datagram of the L: A bit that set to one if this Datagram is the last Datagram of the
PDU. For a PDU which fits in only one Datagram, it is set to one. PDU. For a PDU which fits in only one Datagram, it is set to one.
Note that this is the inverse of the marking technique used by Note that this is the inverse of the marking technique used by
[RFC0791]. [RFC0791].
Datagram Number: 0..127, a monotonically increasing value, modulo Datagram Number: A monotonically increasing 24-bit value which
128, see [RFC1982] which starts at 0 for each PDU. Note that this starts at zero for each PDU. This is used to reassemble frames
does not limit an L3DL PDU to 128 frames. into PDUs a la [RFC0791] Section 2.3. Note that this limits an
L3DL PDU to 2^24 frames.
Datagram Length: Total number of octets in the Datagram including Datagram Length: Total number of octets in the Datagram including
all payloads and fields. all payloads and fields. Note that this limits a datagram to 2^16
octets.
Checksum: A 32 bit hash over the Datagram to detect bit flips, see Checksum: A 32 bit hash over the Datagram to detect bit flips, see
Section 7. Section 7.
Payload: The PDU being transported or a fragment thereof.
7. The Checksum 7. The Checksum
There is a reason conservative folk use a checksum in UDP. And as There is a reason conservative folk use a checksum in UDP. And as
many operators stretch to jumbo frames (over 1,500 octets) longer many operators stretch to jumbo frames (over 1,500 octets) longer
checksums are the prudent approach. checksums are the prudent approach.
For the purpose of computing a checksum, the checksum field itself is For the purpose of computing a checksum, the checksum field itself is
assumed to be zero. assumed to be zero.
The following code describes the suggested algorithm. The following code describes the suggested algorithm.
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8. TLV PDUs 8. TLV PDUs
The basic L3DL application layer PDU is a typical TLV (Type Length The basic L3DL application layer PDU is a typical TLV (Type Length
Value) PDU. It includes a signature to provide optional integrity Value) PDU. It includes a signature to provide optional integrity
and authentication. It may be broken into multiple Datagrams, see and authentication. It may be broken into multiple Datagrams, see
Section 6. Section 6.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Payload Length | ~ | PDU Type | Payload Length ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Payload ... ~ ~ | Payload ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sig Type | Signature Length | ~ | Sig Type | Signature Length | ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
~ Signature ~ ~ Signature |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The fields of the basic L3DL header are as follows: The fields of the basic L3DL header are as follows:
Type: An integer differentiating PDU payload types PDU Type: An integer differentiating PDU payload types. See
Section 22.1.
0 - HELLO
1 - OPEN
2 - KEEPALIVE
3 - ACK
4 - IPv4 Announcement
5 - IPv6 Announcement
6 - MPLS IPv4 Announcement
7 - MPLS IPv6 Announcement
8-254 Reserved
255 - VENDOR
Payload Length: Total number of octets in the Payload field. Payload Length: Total number of octets in the Payload field.
Payload: The application layer content of the L3DL PDU. Payload: The application layer content of the L3DL PDU.
Sig Type: The type of the Signature. Type 0, a null signature, is Sig Type: The type of the Signature, see Section 22.2. Type 0, a
defined in this document. null signature, is defined in this document.
Sig Type 0 indicates a null Signature. For very short PDUs, the Sig Type 0 indicates a null Signature. For a trivial PDU such as
underlying Datagram checksums may be sufficient for integrity, if KEEPALIVE, the underlying Datagram checksum may be sufficient for
not for authentication. integrity, though it lacks authentication.
Other Sig Types may be defined in other documents. Other Sig Types may be defined in other documents.
Signature Length: The length of the Signature, possibly including Signature Length: The length of the Signature, possibly including
padding, in octets. If Sig Type is 0, Signature Length must be 0. padding, in octets. If Sig Type is 0, Signature Length must be 0.
Signature: The result of running the signature algorithm specified Signature: The result of running the signature algorithm specified
in Sig Type over all octets of the PDU except for the Signature in Sig Type over all octets of the PDU except for the Signature
itself. itself.
skipping to change at page 12, line 24 skipping to change at page 13, line 17
L3DL discovers neighbors on logical links and establishes sessions L3DL discovers neighbors on logical links and establishes sessions
between the two ends of all consenting discovered logical links. A between the two ends of all consenting discovered logical links. A
logical link is described by a pair of Logical Link Endpoint logical link is described by a pair of Logical Link Endpoint
Identifiers, LLEIs. Identifiers, LLEIs.
An LLEI is a variable length descriptor which could be an ASN, a An LLEI is a variable length descriptor which could be an ASN, a
classic RouterID, a catenation of the two, an eight octet ISO System classic RouterID, a catenation of the two, an eight octet ISO System
Identifier [RFC1629], or any other identifier unique to a single Identifier [RFC1629], or any other identifier unique to a single
logical link endpoint in the topology. logical link endpoint in the topology.
An L3DL deployment will choose and define an LLEI which suits their An L3DL deployment will choose and define an LLEI which suits its
needs, simple or complex. Two extremes are as follows: needs, simple or complex. Two extremes are as follows:
A simplistic view of a link between two devices is two ports, A simplistic view of a link between two devices is two ports,
identified by unique MAC addresses, carrying a layer 3 protocol identified by unique MAC addresses, carrying a layer 3 protocol
conversation. In this case, the MAC addresses might suffice for the conversation. In this case, the MAC addresses might suffice for the
LLEIs. LLEIs.
Unfortunately, things can get more complex. Multiple VLANs can run Unfortunately, things can get more complex. Multiple VLANs can run
between those two MAC addresses. In practice, many real devices use between those two MAC addresses. In practice, many real devices use
the same MAC address on multiple ports and/or sub-interfaces. the same MAC address on multiple ports and/or sub-interfaces.
skipping to change at page 13, line 18 skipping to change at page 14, line 13
This uniquely identifies the port. This uniquely identifies the port.
For a layer 3 tagged sub-interface or a VLAN/SVI interface, Ifindex For a layer 3 tagged sub-interface or a VLAN/SVI interface, Ifindex
is that of the logical sub-interface, so no further disambiguation is is that of the logical sub-interface, so no further disambiguation is
needed. needed.
L3DL PDUs learned over VLAN-ports may be interpreted by upper layer-3 L3DL PDUs learned over VLAN-ports may be interpreted by upper layer-3
routing protocols as being learned on the corresponding layer-3 SVI routing protocols as being learned on the corresponding layer-3 SVI
interface for the VLAN. interface for the VLAN.
LLEIs are big-endian.
10. HELLO 10. HELLO
WARNING: The second multicast address below is incorrect. We need to
get a new assignment. , which is what we really wanted with the
second address below.
The HELLO PDU is unique in that it is encapsulated in a multicast The HELLO PDU is unique in that it is encapsulated in a multicast
Ethernet frame. It solicits response(s) from other LLEI(s) on the Ethernet frame. It solicits response(s) from other LLEI(s) on the
link. See Section 18.1 for why multicast is used. The destination link. See Section 18.1 for why multicast is used. The destination
multicast MAC Addressees to be used MUST be one of the following, See multicast MAC Addressees to be used MUST be one of the following, See
Clause 9.2.2 of [IEEE802-2014]: Clause 9.2.2 of [IEEE802-2014]:
01-80-C2-00-00-0E: Nearest Bridge = Propagation constrained to a 01-80-C2-00-00-0E: Nearest Bridge = Propagation constrained to a
single physical link; stopped by all types of bridges (including single physical link; stopped by all types of bridges (including
MPRs (media converters)). MPRs (media converters)).
01-80-C2-00-00-03: Nearest non-TPMR Bridge = Propagation constrained To Be Assigned: When a switch receives a frame with a multicast
by all bridges other than TPMRs; intended for use within provider destination MAC it does not recognize, it forwards to all ports.
bridged networks. This destination MAC is to be sent when the interface is known to
be connected to a switch. See Section 23.
All other L3DL PDUs are encapsulated in unicast frames, as the peer's All other L3DL PDUs are encapsulated in unicast frames, as the peer's
destination MAC address is known after the HELLO exchange. destination MAC address is known after the HELLO exchange.
When an interface is turned up on a device, it SHOULD issue a HELLO When an interface is turned up on a device, it SHOULD issue a HELLO.
periodically. The interval is set by configuration with a default of
60 seconds. If a constrained destination address configured, see above, then the
HELLO need not be repeated once a session has been created by an
exchange of OPENs.
If the configured destination address is one that is propagated by
switches, the HELLO SHOULD be repeated at a configured interval, with
a default of 60 seconds. This allows discovery by new devices which
come up on the layer-2 mesh.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0 | Payload Length = 0 | Sig Type = 0 | | PDU Type = 0 | Payload Length = 0 ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ | Sig Type = 0 | Signature Length = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signature Length = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
If more than one device responds, one adjacency is formed for each If more than one device responds, one adjacency is formed for each
unique source LLEI response. L3DL treats each adjacency as a unique source LLEI response. L3DL treats each adjacency as a
separate logical link. separate logical link.
When a HELLO is received from a source LLEI with which there is no When a HELLO is received from a source MAC address with which there
established L3DL adjacency, the receiver SHOULD respond with an OPEN is no established L3DL adjacency, the receiver SHOULD respond with an
PDU. The two devices establish an L3DL adjacency by exchanging OPEN OPEN PDU. The two devices establish an L3DL adjacency by exchanging
PDUs. OPEN PDUs.
The Payload Length is zero as there is no payload. The Payload Length is zero as there is no payload.
HELLO PDUs can not be signed as keying material has yet to be HELLO PDUs can not be signed as keying material has yet to be
exchanged. Hence the signature MUST always be the null type. exchanged. Hence the signature MUST always be the null type.
11. OPEN 11. OPEN
Each device has learned the other's MAC Address from the HELLO Each device has learned the other's MAC Address from the HELLO
exchange, see Section 10. Therefore the OPEN and subsequent PDUs are exchange, see Section 10. Therefore the OPEN and subsequent PDUs are
unicast, as opposed to the HELLO's multicast frame. unicast, as opposed to the HELLO's multicast frame.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 1 | Payload Length | ~ | PDU Type = 1 | Payload Length ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Nonce | LLEI Length | ~ | Nonce ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ~ ~ | LLEI Length | My LLEI |
~ My LLEI ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-~
~ ~ ~ | AttrCount | ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AttrCount | Attribute List ... | ~ Attribute List ... | Auth Type | Key Length ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Auth Type | Key Length | ~ ~ | Key ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~
~ Key ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sig Type | Signature Length | ~ | Serial Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Signature ... ~ | Sig Type | Signature Length | Signature ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Payload Length is the number of octets in all fields of the PDU The Payload Length is the number of octets in all fields of the PDU
from the Nonce through the Key, not including the signature fields. from the Nonce through the Serial Number, not including the three
final signature fields.
The Nonce enables detection of a duplicate OPEN PDU. It SHOULD be The Nonce enables detection of a duplicate OPEN PDU. It SHOULD be
either a random number or the time of day. It is needed to prevent either a random number or a high resolution timestamp. It is needed
session closure due to a repeated OPEN caused by a race or a dropped to prevent session closure due to a repeated OPEN caused by a race or
or delayed ACK. a dropped or delayed ACK.
My LLEI is the sender's LLEI, see Section 9. LLEIs are big-endian. My LLEI is the sender's LLEI, see Section 9.
AttrCount is the number of attributes in the Attribute List. AttrCount is the number of attributes in the Attribute List.
Attributes are single octets whose semantics are user-defined. Attributes are single octets whose semantics are user-defined.
A node may have zero or more user-defined attributes, e.g. spine, A node may have zero or more user-defined attributes, e.g. spine,
leaf, backbone, route reflector, arabica, ... leaf, backbone, route reflector, arabica, ...
Attribute syntax and semantics are local to an operator or Attribute syntax and semantics are local to an operator or
datacenter; hence there is no global registry. Nodes exchange their datacenter; hence there is no global registry. Nodes exchange their
attributes only in the OPEN PDU. attributes only in the OPEN PDU.
Auth Type is the Signature algorithm suite, see Section 8. Auth Type is the Signature algorithm suite, see Section 8.
Key Length is a 16-bit field denoting the length in octets of the Key Length is a 16-bit field denoting the length in octets of the Key
Key, not including the Auth Type or the Key Lengths. If there is no itself, not including the Auth Type or the Key Lengths. If there is
Key, the Auth Type and key Length MUST both be zero. no Key, the Auth Type and key Length MUST both be zero.
The Key is specific to the operational environment. A failure to The Key is specific to the operational environment. A failure to
authenticate is a failure to start the L3DL session, an ERROR PDU is authenticate is a failure to start the L3DL session, an ERROR PDU is
sent (Error Code 2), and HELLOs MUST be restarted. sent (Error Code 2), and HELLOs MUST be restarted.
The Serial Number is that of the last received and processed
Encapsulation PDU. This allows a receiver sending an OPEN to tell
the sender that the receiver wants to resume a session and the sender
only needs to send data more recent than the Serial Number. If this
OPEN is not trying to restart a lost session, the Serial Number MUST
be set to zero.
The Signature fields are described in Section 8 and in an asymmetric The Signature fields are described in Section 8 and in an asymmetric
key environment serve as a proof of possession of the signing auth key environment serve as a proof of possession of the signing auth
data by the sender. data by the sender.
Once two logical link endpoints know each other, and have ACKed each Once two logical link endpoints know each other, and have ACKed each
other's OPEN PDUs, Layer 2 KEEPALIVEs (see Section 14) MAY be started other's OPEN PDUs, Layer 2 KEEPALIVEs (see Section 15) MAY be started
to ensure Layer 2 liveness and keep the session semantics alive. The to ensure Layer 2 liveness and keep the session semantics alive. The
timing and acceptable drop of KEEPALIVE PDUs are discussed in timing and acceptable drop of KEEPALIVE PDUs are discussed in
Section 14. Section 15.
If a sender of OPEN does not receive an ACK of the OPEN PDU Type, If a sender of OPEN does not receive an ACK of the OPEN PDU Type,
then they MUST resend the same OPEN PDU, with the same Nonce. then they MUST resend the same OPEN PDU, with the same Nonce.
Resending an unacknowledged OPEN PDU, like other ACKed PDUs, SHOULD Resending an unacknowledged OPEN PDU, like other ACKed PDUs, SHOULD
use exponential back-off, see [RFC1122]. use exponential back-off, see [RFC1122].
If a properly authenticated OPEN arrives with a new Nonce from an If a properly authenticated OPEN arrives with a new Nonce from an
LLEI with which the receiving logical link endpoint believes it LLEI with which the receiving logical link endpoint believes it
already has an L3DL session (OPENs have already been exchanged), the already has an L3DL session (OPENs have already been exchanged), the
receiver MUST assume that the sending LLEI or entire device has been receiver MAY assume that the sending LLEI or entire device has been
reset. All discovered encapsulation data SHOULD be withdrawn via the reset. If the Serial Number in the OPEN is zero, then all discovered
BGP-LS API and the recipient MUST respond with a new OPEN. In this encapsulation data SHOULD be withdrawn via the BGP-LS API and the
circumstance encapsulations SHOULD NOT be kept because, while the new recipient MUST respond with a new OPEN. In this circumstance
OPEN is likely to be followed by new encapsulation PDUs of the same encapsulations SHOULD NOT be kept.
data, the old session might have an encapsulation type not in the new
session.
12. ACK 12. ACK
The ACK PDU acknowledges receipt of a PDU and reports any error The ACK PDU acknowledges receipt of a PDU and reports any error
condition which might have been raised. condition which might have been raised.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 3 | Payload Length = 5 | PDU Type | | PDU Type = 3 | Payload Length = 5 ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EType | Error Code | Error Hint | ~ | ACKed PDU | EType | Error Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sig Type | Signature Length | ~ | Error Hint | Sig Type |Signature Leng.~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Signature ... ~ ~ | Signature ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The ACK acknowledges receipt of an OPEN, Encapsulation, VENDOR PDU, The ACK acknowledges receipt of an OPEN, Encapsulation, VENDOR PDU,
etc. etc.
The PDU Type is the Type of the PDU being acknowledged, e.g., OPEN or The ACKed PDU is the PDU Type of the PDU being acknowledged, e.g.,
one of the Encapsulations. OPEN or one of the Encapsulations.
If there was an error processing the received PDU, then the EType is If there was an error processing the received PDU, then the EType is
non-zero. If the EType is zero, Error Code and Error Hint MUST also non-zero. If the EType is zero, Error Code and Error Hint MUST also
be zero. be zero.
A non-zero EType is the receiver's way of telling the PDU's sender A non-zero EType is the receiver's way of telling the PDU's sender
that the receiver had problems processing the PDU. The Error Code that the receiver had problems processing the PDU. The Error Code
and Error Hint will tell the sender more detail about the error. and Error Hint will tell the sender more detail about the error.
The decimal value of EType gives a strong hint how the receiver The decimal value of EType gives a strong hint how the receiver
sending the ACK believes things should proceed: sending the ACK believes things should proceed. The ETypes are
listed in Section 22.4. Someone stuck in the 1990s might think of
0 - No Error, Error Code and Error Hint MUST be zero the error codes as 0x1zzz, 0x2zzz, etc. They might be right. Or
1 - Warning, something not too serious happened, continue not.
2 - Session should not be continued, try to restart
3 - Restart is hopeless, call the operator
4-15 - Reserved
Someone stuck in the 1990s might think of the error codes as 0x1zzz,
0x2zzz, etc. They might be right. Or not.
The Error Code indicates the type of error. The Error Code indicates the type of error.
The Error Hint is any additional data the sender of the error PDU The Error Hint is any additional data the sender of the error PDU
thinks will help the recipient or the debugger with the particular thinks will help the recipient or the debugger with the particular
error. error.
The Signature fields are described in Section 8. The Signature fields are described in Section 8.
12.1. Retransmission 12.1. Retransmission
skipping to change at page 17, line 40 skipping to change at page 18, line 48
and/or possibly others not defined here. and/or possibly others not defined here.
The sender of an Encapsulation PDU MUST NOT assume that the peer is The sender of an Encapsulation PDU MUST NOT assume that the peer is
capable of the same Encapsulation Type. An ACK (Section 12) merely capable of the same Encapsulation Type. An ACK (Section 12) merely
acknowledges receipt. Only if both peers have sent the same acknowledges receipt. Only if both peers have sent the same
Encapsulation Type is it safe to assume that they are compatible for Encapsulation Type is it safe to assume that they are compatible for
that type. that type.
A receiver of an encapsulation might recognize an addressing A receiver of an encapsulation might recognize an addressing
conflict, such as both ends of the link trying to use the same conflict, such as both ends of the link trying to use the same
address. In this case, the receiver SHOULD respond with an ERROR address. In this case, the receiver SHOULD respond with an error
(Error Code 1) instead of an ACK. As there may be other usable (Error Code 1) ACK. As there may be other usable addresses or
addresses or encapsulations, this error might log and continue, encapsulations, this error might log and continue, letting an upper
letting an upper layer topology builder deal with what works. layer topology builder deal with what works.
Further, to consider a logical link of a type to formally be Further, to consider a logical link of a type to formally be
established so that it may be pushed up to upper layer protocols, the established so that it may be pushed up to upper layer protocols, the
addressing for the type must be compatible, e.g. on the same IP addressing for the type must be compatible, e.g. on the same IP
subnet. subnet.
13.1. The Encapsulation PDU Skeleton 13.1. The Encapsulation PDU Skeleton
The header for all encapsulation PDUs is as follows: The header for all encapsulation PDUs is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Payload Length | Count | | PDU Type | Payload Length ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Encapsulation List... | ~ | Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sig Type | Signature Length | ~ | Serial Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Signature ... ~ | Encapsulation List... | Sig Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signature Length | Signature ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The 16-bit Count is the number of Encapsulations in the Encapsulation The 24-bit Count is the number of Encapsulations in the Encapsulation
list. list.
An Encapsulation PDU describes zero or more addresses of the An Encapsulation PDU describes zero or more addresses of the
encapsulation type. encapsulation type.
An Encapsulation PDU of Type T replaces all previous encapsulations The Serial Number is a monotonically increasing 32-bit value
of Type T. representing the sender's state in time. It may be an integer, a
timestamp, etc. On session restart (new OPEN), a receiver MAY send
To remove all encapsulations of Type T, the sender uses a Count of the last received Session Number to tell the sender to only send
zero. newer data.
If an LLEI has multiple addresses for an encapsulation type, one and
only one address SHOULD be configured to be marked as primary, see
Section 13.2.
Loopback addresses are generally not seen directly on an external
interface. One or more loopback addresses MAY be exposed by
configuration on one or more L3DL speaking external interfaces, e.g.
for iBGP peering. They SHOULD be marked as such, see Section 13.2.
If there is exactly one non-loopback address for an encapsulation
type on an interface, it SHOULD be marked as primary.
If a sender has multiple links on the same interface, separate data, If a sender has multiple links on the same interface, separate state:
ACKs, etc. must be kept for each peer. data, ACKs, etc. must be kept for each peer.
Over time, multiple Encapsulation PDUs may be sent for an interface Over time, multiple Encapsulation PDUs may be sent for an interface
as configuration changes. as configuration changes.
If the length of an Encapsulation PDU exceeds the Datagram size limit If the length of an Encapsulation PDU exceeds the Datagram size limit
on media, the PDU is broken into multiple Datagrams. See Section 8. on media, the PDU is broken into multiple Datagrams. See Section 8.
The Signature fields are described in Section 8. The Signature fields are described in Section 8.
The Receiver MUST acknowledge the Encapsulation PDU with a Type=3, The Receiver MUST acknowledge the Encapsulation PDU with a Type=3,
skipping to change at page 19, line 20 skipping to change at page 20, line 18
If the Sender does not receive an ACK in a configurable interval If the Sender does not receive an ACK in a configurable interval
(default one second), and the interface is live at layer 2, they (default one second), and the interface is live at layer 2, they
SHOULD retransmit. After a user configurable number of failures, the SHOULD retransmit. After a user configurable number of failures, the
L3DL session should be considered dead and the OPEN process SHOULD be L3DL session should be considered dead and the OPEN process SHOULD be
restarted. restarted.
If the link is broken at layer 2, retransmission MAY BE retried if If the link is broken at layer 2, retransmission MAY BE retried if
data have not changed in the interim. data have not changed in the interim.
13.2. Prim/Loop Flags 13.2. Encapsulaion Flags
0 1 2 3 ... 7 0 1 2 3 4 ... 7
+---------------+---------------+---------------+---------------+ +------------+------------+------------+------------+------------+
| Primary | Loopback | Reserved ... | | | Ann/With | Primary | Under/Over | Loopback | Reserved ..|
+---------------+---------------+---------------+---------------+ +------------+------------+------------+------------+------------+
Each Encapsulation interface address MAY be marked as a primary An Encapsulation PDU of Type T may announce new and/or withdraw old
address, and/or a loopback, in which case the respective bit is set encapsulations of Type T. It indicates this with the Ann/With
to one. Encapsulation Flag, Announce == 1, Withdraw == 0.
Only one address MAY be marked as primary for an encapsulation type. Each Encapsulation interface address in an Encapsulation PDU is
either a new encapsulation be announced (Ann/With == 1) (yes, a la
BGP) or requests one be withdrawn (Ann/With == 0). Adding an
encapsulation which already exists SHOULD raise an Announce/Withdraw
Error (see Section 22.4); the EType SHOULD be 2, suggesting a session
restart (see Section 12 so all encapsulations will be resent.
If an LLEI has multiple addresses for an encapsulation type, one and
only one address SHOULD be configured to be marked as primary
(Primary Flag == 1). Only one address on an interface MAY be marked
as primary for a particular encapsulation type.
An Encapsulation interface address in an Encapsulation PDU MAY be
marked as a loopback, in which case the Loopback bit is set.
Loopback addresses are generally not seen directly on an external
interface. One or more loopback addresses MAY be exposed by
configuration on one or more L3DL speaking external interfaces, e.g.
for iBGP peering. They SHOULD be marked as such, Loopback Flag == 1.
Each Encapsulation interface address in an Encapsulation PDU is that
of the direct 'underlay interface (Under/Over == 1), or an 'overlay'
address (Under/Over == 0), likely that of a VM or container guest
bridged on to the interface with an underlay address.
13.3. IPv4 Encapsulation 13.3. IPv4 Encapsulation
The IPv4 Encapsulation describes a device's ability to exchange IPv4 The IPv4 Encapsulation describes a device's ability to exchange IPv4
packets on one or more subnets. It does so by stating the packets on one or more subnets. It does so by stating the
interface's addresses and the corresponding prefix lengths. interface's addresses and the corresponding prefix lengths.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 4 | Payload Length | Count | | PDU Type = 4 | Payload Length ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | PrimLoop Flags| IPv4 Address | ~ | Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | PrefixLen | more ... | | Serial Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sig Type | Signature Length | ~ | Encaps Flags | IPv4 Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~
~ Signature ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The 16-bit Count is the number of IPv4 Encapsulations. ~ | PrefixLen | more ... | Sig Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signature Length | Signature ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The 24-bit Count is the number of IPv4 Encapsulations.
13.4. IPv6 Encapsulation 13.4. IPv6 Encapsulation
The IPv6 Encapsulation describes a logical link's ability to exchange The IPv6 Encapsulation describes a logical link's ability to exchange
IPv6 packets on one or more subnets. It does so by stating the IPv6 packets on one or more subnets. It does so by stating the
interface's addresses and the corresponding prefix lengths. interface's addresses and the corresponding prefix lengths.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 5 | Payload Length | Count | | PDU Type = 5 | Payload Length ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | PrimLoop Flags| | ~ | Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Serial Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Encaps Flags | |
+-+-+-+-+-+-+-+-+ +
| | | |
+ + + +
| | | |
+ + + +
| IPv6 Address | | IPv6 Address |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | PrefixLen | more ... | | | PrefixLen | more ... | Sig Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sig Type | Signature Length | ~ | Signature Length | Signature ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~
~ Signature ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The 16-bit Count is the number of IPv6 Encapsulations. The 24-bit Count is the number of IPv6 Encapsulations.
13.5. MPLS Label List 13.5. MPLS Label List
As an MPLS enabled interface may have a label stack, see [RFC3032], a As an MPLS enabled interface may have a label stack, see [RFC3032], a
variable length list of labels is needed. variable length list of labels is needed.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label Count | Label | Exp |S| | Label Count | Label | Exp |S|
skipping to change at page 21, line 15 skipping to change at page 23, line 8
13.6. MPLS IPv4 Encapsulation 13.6. MPLS IPv4 Encapsulation
The MPLS IPv4 Encapsulation describes a logical link's ability to The MPLS IPv4 Encapsulation describes a logical link's ability to
exchange labeled IPv4 packets on one or more subnets. It does so by exchange labeled IPv4 packets on one or more subnets. It does so by
stating the interface's addresses the corresponding prefix lengths, stating the interface's addresses the corresponding prefix lengths,
and the corresponding labels. and the corresponding labels.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 6 | Payload Length | Count | | PDU Type = 6 | Payload Length ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | PrimLoop Flags| MPLS Label List ... | ~ | Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | IPv4 Address | | Serial Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | PrefixLen | more ... | | Encaps Flags | MPLS Label List ... | ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sig Type | Signature Length | ~ ~ IPv4 Address | PrefixLen |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Signature ... ~ | more ... | Sig Type | Signature Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signature |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The 16-bit Count is the number of MPLSv6 Encapsulations. The 24-bit Count is the number of MPLSv4 Encapsulations.
13.7. MPLS IPv6 Encapsulation 13.7. MPLS IPv6 Encapsulation
The MPLS IPv6 Encapsulation describes a logical link's ability to The MPLS IPv4 Encapsulation describes a logical link's ability to
exchange labeled IPv6 packets on one or more subnets. It does so by exchange labeled IPv4 packets on one or more subnets. It does so by
stating the interface's addresses, the corresponding prefix lengths, stating the interface's addresses, the corresponding prefix lengths,
and the corresponding labels. and the corresponding labels.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 7 | Payload Length | Count | | PDU Type = 7 | Payload Length ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | PrimLoop Flags| MPLS Label List ... | ~ | Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | | | Serial Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Encaps Flags | MPLS Label List ... | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| | | |
+ + + +
| | | |
+ + + +
| IPv6 Address | | IPv6 Address |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+
| | Prefix Len | more ... | | | Prefix Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sig Type | Signature Length | ~ | more ... | Sig Type | Signature Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Signature ... ~ | Signature ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The 16-bit Count is the number of MPLSv6 Encapsulations. The 24-bit Count is the number of MPLSv6 Encapsulations.
14. KEEPALIVE - Layer 2 Liveness
L3DL devices SHOULD beacon frequent Layer 2 KEEPALIVE PDUs to ensure
session continuity. A receiver may choose to ignore KEEPALIVE PDUs.
An operational deployment MUST BE configured to use KEEPALIVEs or
not, either globally, or down to per-link granularity. Disagreement
MAY result in repeated session break and reestablishment.
KEEPALIVEs SHOULD be beaconed at a configured frequency. One per The MPLS IPv6 Encapsulation describes a logical link's ability to
second is the default. Layer 3 liveness, such as BFD, may be more exchange labeled IPv6 packets on one or more subnets. It does so by
(or less) aggressive. stating the interface's addresses, the corresponding prefix lengths,
and the corresponding labels.
If a KEEPALIVE is not received from a peer with which a receiver has 14. VENDOR - Vendor Extensions
an open session for a configurable time (default 30 seconds), the
link SHOULD BE presumed down. The devices MAY keep configuration
state and restore it without retransmission if no data have changed.
Otherwise, a new session SHOULD BE established and new Encapsulation
PDUs exchanged.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 2 | Payload Length = 0 | Sig Type = 0 | | PDU Type = 255| Payload Length ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signature Length = 0 | ~ | Serial Number ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
15. VENDOR - Vendor Extensions
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 255 | Payload Length | ... | ~ | Enterprise Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Enterprise Number | Ent Type | | Ent Type | Enterprise Data ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Enterprise Data ... | ~ | Sig Type | Signature Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signature ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sig Type | Signature Length | ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~
~ Signature ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Vendors or enterprises may define TLVs beyond the scope of L3DL Vendors or enterprises may define TLVs beyond the scope of L3DL
standards. This is done using a Private Enterprise Number [IANA-PEN] standards. This is done using a Private Enterprise Number [IANA-PEN]
followed by Enterprise Data in a format defined for that Enterprise followed by Enterprise Data in a format defined for that Enterprise
Number and Ent Type. Number and Ent Type.
Ent Type allows a VENDOR PDU to be sub-typed in the event that the Ent Type allows a VENDOR PDU to be sub-typed in the event that the
vendor/enterprise needs multiple PDU types. vendor/enterprise needs multiple PDU types.
As with Encapsulation PDUs, a receiver of a VENDOR PDU MUST respond As with Encapsulation PDUs, a receiver of a VENDOR PDU MUST respond
with an ACK or an ERROR PDU. Similarly, a VENDOR PDU MUST only be with an ACK or an ERROR PDU. Similarly, a VENDOR PDU MUST only be
sent over an open session. sent over an open session.
15. KEEPALIVE - Layer 2 Liveness
L3DL devices SHOULD beacon frequent Layer 2 KEEPALIVE PDUs to ensure
session continuity. A receiver may choose to ignore KEEPALIVE PDUs.
An operational deployment MUST BE configured whether to use
KEEPALIVEs or not, either globally, or down to per-link granularity.
Disagreement MAY result in repeated session break and
reestablishment.
KEEPALIVEs SHOULD be beaconed at a configured frequency. One per
second is the default. Layer 3 liveness, such as BFD, may be more
(or less) aggressive.
If a KEEPALIVE is not received from a peer with which a receiver has
an open session for a configurable time (default 30 seconds), the
link SHOULD BE presumed down. The devices MAY keep configuration
state and restore it without retransmission if no data have changed.
Otherwise, a new session SHOULD BE established and new Encapsulation
PDUs exchanged.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PDU Type = 2 | Payload Length = 0 ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ | Sig Type = 0 | Signature Length = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
16. Layers 2.5 and 3 Liveness 16. Layers 2.5 and 3 Liveness
Layer 2 liveness may be continuously tested by KEEPALIVE PDUs, see Layer 2 liveness may be continuously tested by KEEPALIVE PDUs, see
Section 14. As layer 2.5 or layer 3 connectivity could still break, Section 15. As layer 2.5 or layer 3 connectivity could still break,
liveness above layer 2 MAY be frequently tested using BFD ([RFC5880]) liveness above layer 2 MAY be frequently tested using BFD ([RFC5880])
or a similar technique. or a similar technique.
This protocol assumes that one or more Encapsulation addresses will This protocol assumes that one or more Encapsulation addresses will
be used to ping, BFD, or whatever the operator configures. be used to ping, run BFD, or whatever the operator configures.
17. The North/South Protocol 17. The North/South Protocol
Thus far, a one-hop point-to-point logical link discovery protocol Thus far, a one-hop point-to-point logical link discovery protocol
has been defined. has been defined.
The devices know their unique LLEIs and know the unique peer LLEIs The devices know their unique LLEIs and know the unique peer LLEIs
and Encapsulations on each logical link interface. and Encapsulations on each logical link interface.
Full topology discovery is not appropriate at the L3DL layer, so Full topology discovery is not appropriate at the L3DL layer, so
skipping to change at page 25, line 48 skipping to change at page 28, line 6
As Sub-Interfaces each have their own LLIEs, they act as separate As Sub-Interfaces each have their own LLIEs, they act as separate
interfaces, forming their own links. interfaces, forming their own links.
20. Implementation Considerations 20. Implementation Considerations
An implementation SHOULD provide the ability to configure a logical An implementation SHOULD provide the ability to configure a logical
interface as L3DL speaking or not. interface as L3DL speaking or not.
An implementation SHOULD provide the ability to configure whether An implementation SHOULD provide the ability to configure whether
HELLOs on an L3DL enabled interface send Nearest Bridge or Nearest HELLOs on an L3DL enabled interface send Nearest Bridge or the MAC
non-TPMR Bridge multicast frames from that interface; see Section 10. which is propagated by switches from that interface; see Section 10.
An implementation SHOULD provide the ability to distribute one or An implementation SHOULD provide the ability to distribute one or
more loopback addresses or interfaces into L3DL on an external L3DL more loopback addresses or interfaces into L3DL on an external L3DL
speaking interface. speaking interface.
An implementation SHOULD provide the ability to distribute one or
more overlay and/or underlay addresses or interfaces into L3DL on an
external L3DL speaking interface.
An implementation SHOULD provide the ability to configure one of the An implementation SHOULD provide the ability to configure one of the
addresses of an encapsulation as primary on an L3DL speaking addresses of an encapsulation as primary on an L3DL speaking
interface. If there is only one address for a particular interface. If there is only one address for a particular
encapsulation, the implementation MAY mark it as primary by default. encapsulation, the implementation MAY mark it as primary by default.
An implementation SHOULD allow optional configuration which updates
the local forwarding table with overlay and underlay data both
learned from L3DL peers and configured locally.
21. Security Considerations 21. Security Considerations
The protocol as it is MUST NOT be used outside a datacenter or The protocol as it is MUST NOT be used outside a datacenter or
similarly closed environment due to lack of formal definition of the similarly closed environment due to lack of formal definition of the
authentication and authorization mechanism. Sufficient mechanisms authentication and authorization mechanism. Sufficient mechanisms
may be described in separate documents. may be described in separate documents.
Many MDC operators have a strange belief that physical walls and Many MDC operators have a strange belief that physical walls and
firewalls provide sufficient security. This is not credible. All firewalls provide sufficient security. This is not credible. All
MDC protocols need to be examined for exposure and attack surface. MDC protocols need to be examined for exposure and attack surface.
skipping to change at page 26, line 41 skipping to change at page 29, line 5
divert, intercept, or drop traffic. divert, intercept, or drop traffic.
Similarly, malicious nodes/devices could mis-announce addressing. Similarly, malicious nodes/devices could mis-announce addressing.
If OPENs are not being authenticated, an attacker could forge an OPEN If OPENs are not being authenticated, an attacker could forge an OPEN
for an existing session and cause the session to be reset. for an existing session and cause the session to be reset.
For these reasons, the OPEN PDU's authentication data exchange SHOULD For these reasons, the OPEN PDU's authentication data exchange SHOULD
be used. be used.
If the KEEPALIVE PDU is not signed (as suggested in Section 8) to
save computation, then a MITM could fake a session being alive.
22. IANA Considerations 22. IANA Considerations
22.1. PDU Types
This document requests the IANA create a registry for L3DL PDU Type, This document requests the IANA create a registry for L3DL PDU Type,
which may range from 0 to 255. The name of the registry should be which may range from 0 to 255. The name of the registry should be
L3DL-PDU-Type. The policy for adding to the registry is RFC Required L3DL-PDU-Type. The policy for adding to the registry is RFC Required
per [RFC5226], either standards track or experimental. The initial per [RFC5226], either standards track or experimental. The initial
entries should be the following: entries should be the following:
PDU PDU
Code PDU Name Code PDU Name
---- ------------------- ---- -------------------
0 HELLO 0 HELLO
1 OPEN 1 OPEN
2 KEEPALIVE 2 KEEPALIVE
3 ACK 3 ACK
4 IPv4 Announcement 4 IPv4 Announcement
5 IPv6 Announcement 5 IPv6 Announcement
6 MPLS IPv4 Announcement 6 MPLS IPv4 Announcement
7 MPLS IPv6 Announcement 7 MPLS IPv6 Announcement
8-254 Reserved 8-254 Reserved
255 VENDOR 255 VENDOR
22.2. Signature Type
This document requests the IANA create a registry for L3DL Signature This document requests the IANA create a registry for L3DL Signature
Type, AKA Sig Type, which may range from 0 to 255. The name of the Type, AKA Sig Type, which may range from 0 to 255. The name of the
registry should be L3DL-Signature-Type. The policy for adding to the registry should be L3DL-Signature-Type. The policy for adding to the
registry is RFC Required per [RFC5226], either standards track or registry is RFC Required per [RFC5226], either standards track or
experimental. The initial entries should be the following: experimental. The initial entries should be the following:
Number Name Number Name
------ ------------------- ------ -------------------
0 Null 0 Null
1-255 Reserved 1-255 Reserved
22.3. Flag Bits
This document requests the IANA create a registry for L3DL PL Flag This document requests the IANA create a registry for L3DL PL Flag
Bits, which may range from 0 to 7. The name of the registry should Bits, which may range from 0 to 7. The name of the registry should
be L3DL-PL-Flag-Bits. The policy for adding to the registry is RFC be L3DL-PL-Flag-Bits. The policy for adding to the registry is RFC
Required per [RFC5226], either standards track or experimental. The Required per [RFC5226], either standards track or experimental. The
initial entries should be the following: initial entries should be the following:
Bit Bit Name Bit Bit Name
---- ------------------- ---- -------------------
0 Primary 0 Announce/Withdraw (ann == 0)
1 Loopback 1 Primary
2-7 Reserved 2 Underlay/Overlay (under == 0)
3 Loopback
4-7 Reserved
22.4. Error Codes
This document requests the IANA create a registry for L3DL Error This document requests the IANA create a registry for L3DL Error
Codes, a 16 bit integer. The name of the registry should be L3DL- Codes, a 16 bit integer. The name of the registry should be L3DL-
Error-Codes. The policy for adding to the registry is RFC Required Error-Codes. The policy for adding to the registry is RFC Required
per [RFC5226], either standards track or experimental. The initial per [RFC5226], either standards track or experimental. The initial
entries should be the following: entries should be the following:
Error Error
Code Error Name Code Error Name
---- ------------------- ---- -------------------
0 Reserved 0 No Error
1 Logical Link Addressing Conflict 1 Logical Link Addressing Conflict
2 Authorization Failure in OPEN 2 Authorization Failure in OPEN
3 Signature Failure in PDU 3 Signature Failure in PDU
4 Announce/Withdraw Error
23. IEEE Considerations 23. IEEE Considerations
This document requires a new EtherType. This document requires a new EtherType.
This document requires a new multicast MAC address that will be
broadcast through a switch.
24. Acknowledgments 24. Acknowledgments
The authors thank Cristel Pelsser for multiple reviews, Jeff Haas for The authors thank Cristel Pelsser for multiple reviews, Jeff Haas for
review and comments, Joe Clarke for a useful review, John Scudder for review and comments, Joe Clarke for a useful review, John Scudder for
deeply serious review and comments, Larry Kreeger for a lot of layer deeply serious review and comments, Larry Kreeger for a lot of layer
2 clue, Martijn Schmidt for his contribution, Neeraj Malhotra for 2 clue, Martijn Schmidt for his contribution, Neeraj Malhotra for
review, Russ Housley for checksum discussion and sBox, and Steve review, Russ Housley for checksum discussion and sBox, and Steve
Bellovin for checksum advice. Bellovin for checksum advice.
25. References 25. References
25.1. Normative References 25.1. Normative References
[I-D.ietf-idr-bgp-ls-segment-routing-ext] [I-D.ietf-idr-bgp-ls-segment-routing-ext]
Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H., Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H.,
and M. Chen, "BGP Link-State extensions for Segment and M. Chen, "BGP Link-State extensions for Segment
Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-12 Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-15
(work in progress), March 2019. (work in progress), May 2019.
[I-D.ietf-idr-bgpls-segment-routing-epe] [I-D.ietf-idr-bgpls-segment-routing-epe]
Previdi, S., Talaulikar, K., Filsfils, C., Patel, K., Ray, Previdi, S., Talaulikar, K., Filsfils, C., Patel, K., Ray,
S., and J. Dong, "BGP-LS extensions for Segment Routing S., and J. Dong, "BGP-LS extensions for Segment Routing
BGP Egress Peer Engineering", draft-ietf-idr-bgpls- BGP Egress Peer Engineering", draft-ietf-idr-bgpls-
segment-routing-epe-18 (work in progress), March 2019. segment-routing-epe-19 (work in progress), May 2019.
[I-D.ietf-lsvr-bgp-spf] [I-D.ietf-lsvr-bgp-spf]
Patel, K., Lindem, A., Zandi, S., and W. Henderickx, Patel, K., Lindem, A., Zandi, S., and W. Henderickx,
"Shortest Path Routing Extensions for BGP Protocol", "Shortest Path Routing Extensions for BGP Protocol",
draft-ietf-lsvr-bgp-spf-04 (work in progress), December draft-ietf-lsvr-bgp-spf-04 (work in progress), December
2018. 2018.
[IANA-PEN] [IANA-PEN]
"IANA Private Enterprise Numbers", "IANA Private Enterprise Numbers",
<https://www.iana.org/assignments/enterprise-numbers/ <https://www.iana.org/assignments/enterprise-numbers/
skipping to change at page 29, line 26 skipping to change at page 31, line 49
[RFC1213] McCloghrie, K. and M. Rose, "Management Information Base [RFC1213] McCloghrie, K. and M. Rose, "Management Information Base
for Network Management of TCP/IP-based internets: MIB-II", for Network Management of TCP/IP-based internets: MIB-II",
STD 17, RFC 1213, DOI 10.17487/RFC1213, March 1991, STD 17, RFC 1213, DOI 10.17487/RFC1213, March 1991,
<http://www.rfc-editor.org/info/rfc1213>. <http://www.rfc-editor.org/info/rfc1213>.
[RFC1629] Colella, R., Callon, R., Gardner, E., and Y. Rekhter, [RFC1629] Colella, R., Callon, R., Gardner, E., and Y. Rekhter,
"Guidelines for OSI NSAP Allocation in the Internet", "Guidelines for OSI NSAP Allocation in the Internet",
RFC 1629, DOI 10.17487/RFC1629, May 1994, RFC 1629, DOI 10.17487/RFC1629, May 1994,
<http://www.rfc-editor.org/info/rfc1629>. <http://www.rfc-editor.org/info/rfc1629>.
[RFC1982] Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982,
DOI 10.17487/RFC1982, August 1996,
<http://www.rfc-editor.org/info/rfc1982>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., [RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001, Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
<http://www.rfc-editor.org/info/rfc3032>. <http://www.rfc-editor.org/info/rfc3032>.
skipping to change at page 31, line 11 skipping to change at page 33, line 27
Communication Layers", STD 3, RFC 1122, Communication Layers", STD 3, RFC 1122,
DOI 10.17487/RFC1122, October 1989, DOI 10.17487/RFC1122, October 1989,
<http://www.rfc-editor.org/info/rfc1122>. <http://www.rfc-editor.org/info/rfc1122>.
Authors' Addresses Authors' Addresses
Randy Bush Randy Bush
Arrcus & IIJ Arrcus & IIJ
5147 Crystal Springs 5147 Crystal Springs
Bainbridge Island, WA 98110 Bainbridge Island, WA 98110
United States of America US
Email: randy@psg.com Email: randy@psg.com
Rob Austein Rob Austein
Arrcus, Inc Arrcus, Inc
Email: sra@hactrn.net Email: sra@hactrn.net
Keyur Patel Keyur Patel
Arrcus Arrcus
2077 Gateway Place, Suite #400 2077 Gateway Place, Suite #400
San Jose, CA 95119 San Jose, CA 95119
United States of America US
Email: keyur@arrcus.com Email: keyur@arrcus.com
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