Network Working Group H. Chen
Internet-Draft M. McBride
Intended status: Standards Track Futurewei
Expires: October 16, 2021 A. Wang
China Telecom
G. Mishra
Verizon Inc.
Y. Fan
Casa Systems
L. Liu
Fujitsu
X. Liu
Volta Networks
April 14, 2021
IS-IS Extensions for BIER-TE
draft-chen-bier-te-isis-00
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 October 16, 2021.
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Copyright Notice
Copyright (c) 2021 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
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Extensions to IS-IS . . . . . . . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
[I-D.ietf-bier-te-arch] 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.
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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.
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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. Note that if each of BitPosition
and DrEndBitPosition uses more than 2 octets, we use 4 or more octets
for each of them.
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3. Security Considerations
TBD.
4. IANA Considerations
Under "Sub-TLVs for TLVs 22, 23, 25, 141, 222, and 223" for IS-IS TLV
Codepoints, IANA is requested to assign a new codepoint for BIER-TE
Info Sub-TLV as follows:
+============+=============+==+==+==+===+===+===+=============+
|Sub-TLV Type|Sub-TLV Name |22|23|25|141|222|223|reference |
+============+=============+==+==+==+===+===+===+=============+
| TBD1 |BIER-TE Info |y |n |n | n | y | n |This document|
+------------+-------------+--+--+--+---+---+---+-------------+
5. Acknowledgements
The authors would like to thank people for their comments to this
work.
6. References
6.1. Normative References
[I-D.ietf-bier-te-arch]
Eckert, T., Cauchie, G., and M. Menth, "Tree Engineering
for Bit Index Explicit Replication (BIER-TE)", draft-ietf-
bier-te-arch-09 (work in progress), October 2020.
[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>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<https://www.rfc-editor.org/info/rfc5226>.
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[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>.
[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>.
[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, November 2017,
<https://www.rfc-editor.org/info/rfc8279>.
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, January
2018, <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, June 2018,
<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, April
2019, <https://www.rfc-editor.org/info/rfc8556>.
Authors' Addresses
Huaimo Chen
Futurewei
Boston, MA
USA
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
USA
Phone: 301 502-1347
Email: gyan.s.mishra@verizon.com
Yanhe Fan
Casa Systems
USA
Email: yfan@casa-systems.com
Lei Liu
Fujitsu
USA
Email: liulei.kddi@gmail.com
Xufeng Liu
Volta Networks
McLean, VA
USA
Email: xufeng.liu.ietf@gmail.com
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