Internet-Draft ISIS for BIER-TE December 2022
Chen, et al. Expires 25 June 2023 [Page]
Workgroup:
Network Working Group
Internet-Draft:
draft-ietf-bier-te-isis-03
Published:
Intended Status:
Standards Track
Expires:
Authors:
H. Chen
Futurewei
M. McBride
Futurewei
A. Wang
China Telecom
G. Mishra
Verizon Inc.
Y. Fan
Casa Systems
L. Liu
Fujitsu
X. Liu
IBM Corporation

IS-IS Extensions for BIER-TE

Abstract

This document describes IS-IS extensions for distributing BitPositions configured on the links in "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 working documents as Internet-Drafts. The list of current Internet-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 time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on 25 June 2023.

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. A link in a BIER-TE domain has its BitPositions. For a link between two nodes X and Y, there are two BitPositions for two forward connected adjacencies. These two adjacency BitPositions could be configured on nodes X and Y respectively. The BitPosition configured on X is the forward connected adjacency of Y. The BitPosition configured on Y is the forward connected adjacency of X.

This document proposes IS-IS extensions for distributing BitPositions configured on the links in "Bit Index Explicit Replication Traffic Engineering" (BIER-TE) domain.

1.1. Terminology

BIER:
Bit Index Explicit Replication.
BIER-TE:
BIER Traffic Engineering.
BFR:
Bit-Forwarding Router.
BFIR:
Bit-Forwarding Ingress Router.
BFER:
Bit-Forwarding Egress Router.
BFR-id:
BFR Identifier. It is a number in the range [1,65535].
BFR-NBR:
BFR Neighbor.
IS-IS:
Intermediate System to Intermediate System.

2. Extensions to IS-IS

This section describes protocol extensions to IS-IS for distributing BIER-TE information such as the BitPositions configured on the links in a BIER-TE domain.

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.

BIER-TE Info 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 the BIER-TE information about a link or interface.

    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     | sub-domain-id |      BAR      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      IPA      |         BitPosition           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     DisEndBitPosition         |    Sub-Sub-TLVs (variable)    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
   |                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: BIER-TE Info Sub-TLV
Type:
TBD1 is to be assigned by IANA.
Length:
Variable, dependent on Sub-Sub-TLVs.
sub-domain-id:
Unique value identifying a BIER-TE sub-domain.
BAR:
Single-octet BIER Algorithm used to calculate underlay paths to reach other BFRs. Values are allocated from the "BIER Algorithm" registry defined in [RFC8401].
IPA:
Single-octet IGP Algorithm used to either modify, enhance, or replace the calculation of underlay paths to reach other BFRs as defined by the BAR value. Values are defined in the "IGP Algorithm Types" registry.
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 connection on the designated Intermediate Systems (Dis) end. This field is valid when the neighbor is a pseudonode. If the neighbor is not a pseudonode, this field MUST be ignored. The DisEndBitPosition may be configured on the link/interface to a transit network (i.e., broadcast link or say LAN).

No Sub-Sub-TLV is defined so far.

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 BIER-TE Info as follows:

  +=======+=============+==+==+==+===+===+===+=============+
  | Type  |Description  |22|23|25|141|222|223|reference    |
  +=======+=============+==+==+==+===+===+===+=============+
  | TBD1  |BIER-TE Info |y |y |n | n | y | y |This document|
  +-------+-------------+--+--+--+---+---+---+-------------+

5. Acknowledgements

The authors would like to thank Les Ginsberg, Tony Przygienda and Acee Lindem for their comments on this work.

6. References

6.1. Normative References

[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <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, , <https://www.rfc-editor.org/info/rfc5120>.
[RFC5226]
Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 5226, DOI 10.17487/RFC5226, , <https://www.rfc-editor.org/info/rfc5226>.
[RFC5305]
Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, DOI 10.17487/RFC5305, , <https://www.rfc-editor.org/info/rfc5305>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8279]
Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., Przygienda, T., and S. Aldrin, "Multicast Using Bit Index Explicit Replication (BIER)", RFC 8279, DOI 10.17487/RFC8279, , <https://www.rfc-editor.org/info/rfc8279>.
[RFC9262]
Eckert, T., Ed., Menth, M., and G. Cauchie, "Tree Engineering for Bit Index Explicit Replication (BIER-TE)", RFC 9262, DOI 10.17487/RFC9262, , <https://www.rfc-editor.org/info/rfc9262>.

6.2. Informative References

[RFC8296]
Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation for Bit Index Explicit Replication (BIER) in MPLS and Non-MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, , <https://www.rfc-editor.org/info/rfc8296>.
[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, , <https://www.rfc-editor.org/info/rfc8401>.
[RFC8556]
Rosen, E., Ed., Sivakumar, M., Przygienda, T., Aldrin, S., and A. Dolganow, "Multicast VPN Using Bit Index Explicit Replication (BIER)", RFC 8556, DOI 10.17487/RFC8556, , <https://www.rfc-editor.org/info/rfc8556>.

Authors' Addresses

Huaimo Chen
Futurewei
Boston, MA,
United States of America
Mike McBride
Futurewei
Aijun Wang
China Telecom
Beiqijia Town, Changping District
Beijing
102209
China
Gyan S. Mishra
Verizon Inc.
13101 Columbia Pike
Silver Spring, MD 20904
United States of America
Phone: 301 502-1347
Yanhe Fan
Casa Systems
United States of America
Lei Liu
Fujitsu
United States of America
Xufeng Liu
IBM Corporation
United States of America