Internet DRAFT - draft-ietf-bier-te-isis
draft-ietf-bier-te-isis
Network Working Group H. Chen
Internet-Draft M. McBride
Intended status: Standards Track Futurewei
Expires: 10 July 2024 A. Wang
China Telecom
G. Mishra
Verizon Inc.
Y. Fan
Casa Systems
L. Liu
Fujitsu
X. Liu
Alef Edge
7 January 2024
IS-IS Extensions for BIER-TE
draft-ietf-bier-te-isis-09
Abstract
This document describes IS-IS extensions for distributing the
BitPositions configured on a Bit-Forwarding Router (BFR) in a "Bit
Index Explicit Replication Traffic Engineering" (BIER-TE) domain.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119] [RFC8174]
when, and only when, they appear in all capitals, as shown here.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 10 July 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
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Extensions to IS-IS . . . . . . . . . . . . . . . . . . . . . 3
2.1. Link BitPosition . . . . . . . . . . . . . . . . . . . . 3
2.2. Routed and Localdecap BitPositions . . . . . . . . . . . 4
3. Security Considerations . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.1. Normative References . . . . . . . . . . . . . . . . . . 6
5.2. Informative References . . . . . . . . . . . . . . . . . 7
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
[RFC9262] introduces Bit Index Explicit Replication (BIER) Traffic/
Tree Engineering (BIER-TE). It is an architecture for per-packet
stateless explicit point to multipoint (P2MP) multicast path/tree.
There are three types of BitPositions (BPs) in a BIER-TE domain: link
BitPosition (BP), routed BP and localdecap BP. A link BP is a BP
configured on a link from Bit-Forwarding Router (BFR) X to BFR Y for
a forward connected adjacency from X to Y. A routed BP is a BP
configured on BFR X for a forward routed adjacency from X to a remote
BFR Z not directly connected to X. A localdecap BP is a BP
configured on a BFR.
[RFC8401] describes IS-IS Extensions for distributing the BFR
identifier (BFR-id) configured on a BFR. This document specifies IS-
IS extensions for distributing the BitPositions configured a BFR in a
BIER-TE domain. The BitPositions distributed may be used by a BFR as
a Point of Local Repair (PLR) for Fast-ReRoute (FRR).
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2. Extensions to IS-IS
This section describes protocol extensions to IS-IS for distributing
the BitPositions configured on a BFR in a BIER-TE domain.
2.1. Link BitPosition
An Extended IS Reachability TLV (Type 22) defined in [RFC5305] may
contain Sub-TLVs (such as those for TE) that apply to a link/
interface to a neighbor. To encode multiple links or interfaces to
neighbors, the structure inside TLV is repeated.
MT Intermediate Systems TLV (Type 222) defined in [RFC5120] may
contain Sub-TLVs (such as those for TE) that apply to a link/
interface. It is aligned with Extended IS Reachability TLV (Type 22)
beside an additional two bytes in front at the beginning of the TLV
for MT-ID.
Link-BP Sub-TLV of the following format is defined and used in
Extended IS Reachability TLV (Type 22) and/or MT Intermediate Systems
TLV (Type 222) to advertise a link BP.
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 (TBD1) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BAR | IPA | sub-domain-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BitPosition | DisEndBitPosition |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Sub-Sub-TLVs (variable) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Link-BP Sub-TLV
Type: TBD1 is to be assigned by IANA.
Length: Variable, dependent on Sub-Sub-TLVs.
BAR, IPA and sub-domain-id: They are defined in Section 6.1 of
[RFC8401].
BitPosition: A 2-octet field encoding the BitPosition locally
configured on the link/interface to an Intermediate System
neighbor.
DisEndBitPosition: A 2-octet field encoding the BitPosition of the
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connection on the designated Intermediate Systems (Dis) end.
This field exists when the neighbor is a pseudonode. If the
neighbor is not a pseudonode, this field MUST NOT exist. The
DisEndBitPosition may be configured on the link/interface to a
transit network (i.e., broadcast link or say LAN) as described
in [I-D.chen-bier-te-lan].
No Sub-Sub-TLVs are currently defined.
2.2. Routed and Localdecap BitPositions
A Sub-TLV, called Node BPs Sub-TLV, is defined and carried within the
TLVs 235, 237 [RFC5120], 135 [RFC5305], or 236 [RFC5308]. It
contains Sub-Sub-TLVs. Two types of Sub-Sub-TLVs are defined. One
is for a Routed BitPosition and the other for a Localdecap
BitPosition. The Node BPs Sub-TLV 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 (TBD2) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BAR | IPA | sub-domain-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-Sub-TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Node BPs Sub-TLV
Type: TBD2 is to be assigned by IANA.
Length: Variable.
BAR, IPA and sub-domain-id: They are defined in Section 6.1 of
[RFC8401].
Sub-Sub-TLVs: They are Routed-BP Sub-Sub-TLVs for Routed BPs and/or
Localdecap-BP Sub-Sub-TLV for Localdecap BP.
The Routed-BP Sub-Sub-TLV 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 (1) | Length(4) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BitPosition | BFR-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure 3: Routed-BP Sub-Sub-TLV
Type: 1 is the type for routed BP.
Length: It is 4.
BitPosition: A 2-octet field encoding the BitPosition configured on
a BFR for a forward routed adjacency to a remote BFR.
BFR-id: A 2-octet field encoding the BFR-id of the remote BFR.
The Localdecap-BP Sub-Sub-TLV 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 (2) | Length(2) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BitPosition |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Localdecap-BP Sub-Sub-TLV
Type: 2 is the type for localdecap BP.
Length: It is 2.
BitPosition: A 2-octet field encoding the localdecap BitPosition
configured on a BFR.
3. Security Considerations
Protocol extensions defined in this document do not affect the IS-IS
security.
4. IANA Considerations
Under "IS-IS Sub-TLVs for TLVs Advertising Neighbor Information"
registry, IANA is requested to assign a new Sub-TLV Type for Link BP
as follows:
+=======+=============+==+==+==+===+===+===+=============+
| Type |Description |22|23|25|141|222|223|reference |
+=======+=============+==+==+==+===+===+===+=============+
| TBD1 | Link BP |y |y |n | n | y | y |This document|
+-------+-------------+--+--+--+---+---+---+-------------+
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Under "IS-IS Sub-TLVs for TLVs Advertising Prefix Reachability"
registry, IANA is requested to assign a new Sub-TLV Type for Node BPs
as follows:
+=======+=============+==+===+===+===+===+=============+
| Type |Description |27|135|235|236|237|reference |
+=======+=============+==+===+===+===+===+=============+
| TBD2 | Node BPs |n | y | y | y | y |This document|
+-------+-------------+--+---+---+---+---+-------------+
IANA is requested to create a new sub-registry "Sub-Sub-TLVs for Node
BPs Sub-TLV" as follows:
+==============+===================+=====================+
| Type | Name | reference |
+==============+===================+=====================+
| 0 | Reserved |
+--------------+-------------------+---------------------+
| 1 | Routed BP | This document |
+--------------+-------------------+---------------------+
| 2 | Localdecap BP | This document |
+--------------+-------------------+---------------------+
| 3 - 255 | Unassigned |
+--------------+-------------------+---------------------+
5. References
5.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120,
DOI 10.17487/RFC5120, February 2008,
<https://www.rfc-editor.org/info/rfc5120>.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, DOI 10.17487/RFC5305, October
2008, <https://www.rfc-editor.org/info/rfc5305>.
[RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308,
DOI 10.17487/RFC5308, October 2008,
<https://www.rfc-editor.org/info/rfc5308>.
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[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC9262] Eckert, T., Ed., Menth, M., and G. Cauchie, "Tree
Engineering for Bit Index Explicit Replication (BIER-TE)",
RFC 9262, DOI 10.17487/RFC9262, October 2022,
<https://www.rfc-editor.org/info/rfc9262>.
5.2. Informative References
[I-D.chen-bier-te-lan]
Chen, H., McBride, M., Wang, A., Mishra, G. S., Liu, L.,
and X. Liu, "BIER-TE for Broadcast Link", Work in
Progress, Internet-Draft, draft-chen-bier-te-lan-08, 18
October 2023, <https://datatracker.ietf.org/doc/html/
draft-chen-bier-te-lan-08>.
[RFC8401] Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z.
Zhang, "Bit Index Explicit Replication (BIER) Support via
IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018,
<https://www.rfc-editor.org/info/rfc8401>.
Acknowledgments
The authors would like to thank Acee Lindem, Les Ginsberg, Tony
Przygienda, Jeffrey Zhang and Toerless Eckert for their comments on
this work.
Authors' Addresses
Huaimo Chen
Futurewei
Boston, MA,
United States of America
Email: Huaimo.chen@futurewei.com
Mike McBride
Futurewei
Email: michael.mcbride@futurewei.com
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Aijun Wang
China Telecom
Beiqijia Town, Changping District
Beijing
102209
China
Email: wangaj3@chinatelecom.cn
Gyan S. Mishra
Verizon Inc.
13101 Columbia Pike
Silver Spring, MD 20904
United States of America
Phone: 301 502-1347
Email: gyan.s.mishra@verizon.com
Yanhe Fan
Casa Systems
United States of America
Email: yfan@casa-systems.com
Lei Liu
Fujitsu
United States of America
Email: liulei.kddi@gmail.com
Xufeng Liu
Alef Edge
United States of America
Email: xufeng.liu.ietf@gmail.com
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