Advertisement of Remote Interface Identifiers for Layer 2 Bundle Members
draft-glctgp-lsr-l2-bundle-member-remote-id-00
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Liyan Gong , Changwang Lin , Mengxiao Chen , Ketan Talaulikar , Les Ginsberg , Peter Psenak | ||
| Last updated | 2024-03-16 | ||
| Replaces | draft-gong-lsr-lldp-interface-id | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-glctgp-lsr-l2-bundle-member-remote-id-00
LSR Working Group L. Gong
Internet Draft China Mobile
Intended status: Standards Track C. Lin
Expires: September 13, 2024 M. Chen
New H3C Technologies
K. Talaulikar
L. Ginsberg
P. Psenak
Cisco Systems
March 17, 2024
Advertisement of Remote Interface Identifiers for Layer 2 Bundle
Members
draft-glctgp-lsr-l2-bundle-member-remote-id-00
Abstract
This document describes how OSPF and IS-IS would advertise the
remote interface identifiers for Layer 2 bundle members. The
corresponding extension of BGP-LS is also specified.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 13, 2024.
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Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction...................................................2
1.1. Requirements Language.....................................3
2. Use Case.......................................................3
3. Advertising L2 Bundle Member Remote Interface Identifier.......4
4. OSPF Extension.................................................5
5. IS-IS Extension................................................5
6. BGP-LS Extension...............................................6
7. Acquirement of Remote Interface Identifier.....................7
8. Security Considerations........................................7
9. IANA Considerations............................................7
10. References....................................................8
10.1. Normative References.....................................8
10.2. Informational References.................................9
Authors' Addresses................................................9
1. Introduction
BGP-LS [RFC9552] is widely used for collection of topology
information from IGPs. In networks where Layer 2 (L2) interface
bundles (for instance, a Link Aggregation Group (LAG) [IEEE802.1AX])
are deployed, the connectivity relationships between bundle members
may be required to be collected by a controller for traffic
engineering purposes.
When advertising L2 bundles in OSPF [RFC9356] and IS-IS [RFC8668], a
member link is described by its local interface identifier, also
referred to as a link local identifier. If the remote interface
identifier could be advertised for each member link, the pairing
relationships between the local and remote interfaces would be
clear.
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This document describes the mechanism for advertising the remote
interface identifier for Layer 2 bundle members in OSPF and IS-IS.
The BGP-LS extension for advertising L2 bundle member interface
remote identifier is also specified in this document.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Use Case
Figure 1 shows a network, in which an L2 bundle is deployed between
R1 and R2. The controller collects the topology information from R3
via BGP-LS.
+----------+ BGP-LS
|Controller|<********************
+----------+ *
*
*
*
+----+ L2-Bundle +----+ +----+
| | /-------member 1-------\ | | | |
| | / \ | | | |
| R1 +----------member 2----------+ R2 +---+ R3 +
| | \ / | | | |
| | \-------member 3-------/ | | | |
+----+ +----+ +----+
Figure 1
The network operator may want to control bidirectional traffic flows
on the individual member links of the underlying Layer 2 bundle for
TE purposes. The real-time bandwidth, delay, and link loss might be
measured for each bundle member at both ends. Labels or SIDs might
be allocated for each bundle member at both ends. So, there would be
requirements for the controller to figure out the connectivity
relationships between bundle members.
This document defines a mechanism for IGP routers to advertise the
remote interface identifiers for each L2 bundle member, along with
the corresponding mechanism for the controller to collect such
information via BGP-LS.
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3. Advertising L2 Bundle Member Remote Interface Identifier
In OSPF, the remote interface identifiers of L2 bundle members are
advertised as follows.
OSPFv2 Extended Link TLV, or OSPFv3 Router-Link TLV, for L3 Link:
L2 Bundle Member Attributes TLV:
L2 Bundle Member Descriptor of Member #1
L2 Bundle Member Interface Remote Identifier Sub-TLV (Optional -
as defined in Section 4)
L2 Bundle Member Attributes TLV:
L2 Bundle Member Descriptor of Member #2
L2 Bundle Member Interface Remote Identifier Sub-TLV (Optional -
as defined in Section 4)
...
L2 Bundle Member Attributes TLV:
L2 Bundle Member Descriptor of Member #n
L2 Bundle Member Interface Remote Identifier Sub-TLV (Optional -
as defined in Section 4)
In IS-IS, the remote interface identifiers of L2 bundle members are
advertised as follows. Note that IS-IS can advertise a set of
members in a single L2 Bundle Member Attribute Descriptor, so the L2
Bundle Member Interface Remote Identifier Sub-TLV MUST carry
multiple remote interface identifiers, one for each of the bundle
members advertised in the associated L2 Bundle Member Descriptor.
L2 Bundle Member Attributes TLV:
Parent L3 Neighbor Descriptor
Length of L2 Bundle Attribute Descriptor
Number of L2 Bundle Member Descriptors
L2 Bundle Member Link Local Identifiers of Member #1,#2,...,#n
Sub-TLV(s)
L2 Bundle Member Interface Remote Identifier Sub-TLV (Optional -
as defined in Section 5) for Member #1,#2,...,#n
In BGP-LS, the remote interface identifiers of L2 bundle members are
advertised as follows.
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NLRI for L3 Link R1->R2
Attributes:
L2 Bundle Member Attributes TLV:
L2 Bundle Member Descriptor of Member #1
L2 Bundle Member Interface Remote Identifier Sub-TLV (Optional -
as defined in Section 6)
L2 Bundle Member Attributes TLV:
L2 Bundle Member Descriptor of Member #2
L2 Bundle Member Interface Remote Identifier Sub-TLV (Optional -
as defined in Section 6)
...
L2 Bundle Member Attributes TLV:
L2 Bundle Member Descriptor of Member #n
L2 Bundle Member Interface Remote Identifier Sub-TLV (Optional -
as defined in Section 6)
4. OSPF Extension
This document defines a new L2 Bundle Member Interface Remote
Identifier Sub-TLV in both OSPFv2 and OSPFv3. This Sub-TLV is used
to advertise the remote interface identifier for a L2 bundle member.
It can be carried as a sub-TLV of the OSPF L2 Bundle Member
Attributes TLV [RFC9356]. It has the following format:
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 (TBA) | Length (4) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote Interface ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TBA.
o Length: 4.
o Remote Interface ID: Remote identifier of interface, 4 octets.
A remote interface ID with value of zero is not valid and MUST be
ignored and handled as if the sub-TLV was not present.
5. IS-IS Extension
This document defines a new L2 Bundle Member Interface Remote
Identifier Sub-TLV in IS-IS. This Sub-TLV is used to advertise the
remote interface identifiers for L2 bundle members.
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It can be carried as a sub-TLV of the IS-IS L2 Bundle Member
Attributes TLV [RFC8668]. It has the following format:
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 (TBA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote Interface ID 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote Interface ID N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TBA.
o Length: 4 * Number of L2 Bundle Member Descriptors.
o Remote Interface ID: Remote identifier of interface, 4 octets.
There MUST be one Remote Interface ID for each of the L2 Bundle
Members advertised under the associated L2 Bundle Member Attribute
Descriptor. A remote interface ID with value of zero MUST be ignored
and handled as if the value was unknown.
6. BGP-LS Extension
This document defines a new L2 Bundle Member Interface Remote
Identifier Sub-TLV in BGP-LS. This Sub-TLV is derived from the
Remote Interface Identifier Sub-TLV of OSPF (Section 3) and IS-IS
(Section 4).
It can be carried as a sub-TLV of the BGP-LS L2 Bundle Member
Attributes TLV [RFC9085]. It has the following format:
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 (TBA) | Length (4) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote Interface ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TBA.
o Length: 4.
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o Remote Interface ID: Remote identifier of interface, 4 octets.
A remote interface ID with value of zero is not valid and MUST be
ignored and handled as if the sub-TLV was not present.
7. Acquirement of Remote Interface Identifier
IGPs have no direct way to exchange L2 bundle member link
identifiers since the Layer 3 protocol is not operating directly on
the bundle members. Some L2 protocols may be used to get the remote
interface identifiers for bundle members. This may be discovered via
[IEEE802.1AX] when used to form the LAG bundle. A router may also
run LLDP [802.1AB] on the bundle members to exchange local interface
identifiers with its neighbor, by using the LLDP Management Address
TLV.
How the remote interface identifier is obtained is out of the scope
of this document.
8. Security Considerations
TBD.
9. IANA Considerations
This document adds the following new sub-TLV to the "OSPFv2 Extended
Link TLV Sub-TLVs" registry.
+------+----------------------------------------------+----+
| Type | Designation |L2BM|
+======+==============================================+====+
| TBA | L2 Bundle Member Interface Remote Identifier | Y |
+------+----------------------------------------------+----+
This document adds the following new sub-TLV to the "OSPFv3
Extended-LSA Sub-TLVs" registry.
+------+----------------------------------------------+----+
| Type | Description |L2BM|
+======+==============================================+====+
| TBA | L2 Bundle Member Interface Remote Identifier | Y |
+------+----------------------------------------------+----+
This document adds the following new sub-TLV to the "IS-IS Sub-TLVs
for TLVs Advertising Neighbor Information" registry.
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+------+-----------------------------+---+---+---+---+---+---+
| Type | Description | 22| 23| 25|141|222|223|
+======+=============================+===+===+===+===+===+===+
| TBA | L2 Bundle Member | n | n | y | n | n | n |
| | Interface Remote Identifier | | | | | | |
+------+-----------------------------+---+---+---+---+---+---+
This document adds the following new sub-TLV to the "BGP-LS NLRI and
Attribute TLVs" registry.
+------+----------------------------------------------+
| Type | Description |
+======+==============================================+
| TBA | L2 Bundle Member Interface Remote Identifier |
+------+----------------------------------------------+
10. References
10.1. Normative References
[IEEE802.1AX]
IEEE, "IEEE Standard for Local and Metropolitan Area
Networks--Link Aggregation", IEEE Std 802.1AX, DOI
10.1109/IEEESTD.2020.9105034, May 2020,
<https://doi.org/10.1109/IEEESTD.2020.9105034>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, May 2017
[RFC8668] Ginsberg, L., Ed., Bashandy, A., Filsfils, C., Nanduri,
M., and E. Aries, "Advertising Layer 2 Bundle Member Link
Attributes in IS-IS", RFC 8668, DOI 10.17487/RFC8668,
December 2019, <https://www.rfc-editor.org/info/rfc8668>.
[RFC9085] Previdi, S., Talaulikar, K., Ed., Filsfils, C., Gredler,
H., and M. Chen, "Border Gateway Protocol - Link State
(BGP-LS) Extensions for Segment Routing", RFC 9085, DOI
10.17487/RFC9085, August 2021, <https://www.rfc-
editor.org/info/rfc9085>.
[RFC9356] Talaulikar, K. and P. Psenak, "Advertising L2 Bundle
Member Link Attributes in OSPF", RFC 9356, January 2023,
<https://www.rfc-editor.org/info/rfc9356>.
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10.2. Informational References
[802.1AB] "IEEE Standard for Local and metropolitan area networks-
Station and Media Access Control Connectivity Discovery",
IEEE Std 802.1AB-2016, 29 January 2016.
[RFC9552] Talaulikar, K., Ed., "Distribution of Link-State and
Traffic Engineering Information Using BGP", RFC 9552, DOI
10.17487/RFC9552, December 2023, <https://www.rfc-
editor.org/info/rfc9552>.
Authors' Addresses
Liyan Gong
China Mobile
China
Email: gongliyan@chinamobile.com
Changwang Lin
New H3C Technologies
China
Email: linchangwang.04414@h3c.com
Mengxiao Chen
New H3C Technologies
China
Email: chen.mengxiao@h3c.com
Ketan Talaulikar
Cisco Systems
India
Email: ketant.ietf@gmail.com
Les Ginsberg
Cisco Systems
United States of America
Email: ginsberg@cisco.com
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Peter Psenak
Cisco Systems
Apollo Business Center
Mlynske nivy 43
Bratislava 821 09
Slovakia
Email: ppsenak@cisco.com
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