OSPFv2 Extensions for BIER-TE
draft-ietf-bier-te-ospf-05
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| Authors | Huaimo Chen , Mike McBride , Aijun Wang , Gyan Mishra , Yanhe Fan , Lei Liu , Xufeng Liu | ||
| Last updated | 2023-04-27 (Latest revision 2023-03-09) | ||
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draft-ietf-bier-te-ospf-05
Network Working Group H. Chen
Internet-Draft M. McBride
Intended status: Standards Track Futurewei
Expires: 29 October 2023 A. Wang
China Telecom
G. Mishra
Verizon Inc.
Y. Fan
Casa Systems
L. Liu
Fujitsu
X. Liu
IBM Corporation
27 April 2023
OSPFv2 Extensions for BIER-TE
draft-ietf-bier-te-ospf-05
Abstract
This document describes OSPFv2 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
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 29 October 2023.
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Copyright Notice
Copyright (c) 2023 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Extensions to OSPFv2 . . . . . . . . . . . . . . . . . . . . 3
2.1. Link BitPosition . . . . . . . . . . . . . . . . . . . . 3
2.2. Routed and Localdecap BitPositions . . . . . . . . . . . 5
3. Security Considerations . . . . . . . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.1. Normative References . . . . . . . . . . . . . . . . . . 7
5.2. Informative References . . . . . . . . . . . . . . . . . 8
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
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.
[RFC8444] describes OSPFv2 Extensions for distributing the BFR
identifier (BFR-id) configured on a BFR. This document specifies
OSPFv2 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 OSPFv2
This section describes protocol extensions to OSPFv2 for distributing
the BitPositions configured on a BFR in a BIER-TE domain.
2.1. Link BitPosition
This section defines a Sub-TLV for distributing a link BitPosition
(BP).
[RFC7684] defines the OSPFv2 Extended Link TLV to advertise the
information about a link. Multiple Link TLVs for the links of a
router are included in the OSPFv2 Extended Link Opaque LSA of the
router. The OSPFv2 Extended Link 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 (Variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs (variable) |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: OSPFv2 Extended Link TLV
Type: 1.
Length: Variable, dependent on Sub-TLVs.
Link Type, Link ID and Link Data: They are defined in Section A.4.2
of [RFC2328].
Reserved: MUST be set to 0 on transmission and MUST be ignored on
reception.
Under the OSPFv2 Extended Link TLV for a link, a Sub-TLV, called
Link-BP Sub-TLV, is defined for distributing a link BitPosition. A
Link-BP Sub-TLV is included in the Link TLV for a link of Link Type
P2P (Point-to-Point) or Broadcast (or say LAN or Transit Network).
The Link-BP Sub-TLV has the following format:
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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(6/8) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-domain-id | MT-ID | BAR | IPA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BitPosition | DrEndBitPosition |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Link-BP Sub-TLV
Type: TBD1 is to be assigned by IANA.
Length: Variable. For a P2P link, it is 6 since there is no
DrEndBitPosition. For a broadcast link, it is 8 since there is
a DrEndBitPosition.
sub-domain-id: Unique value identifying a BIER-TE sub-domain.
MT-ID: Multi-Topology ID identifying the topology that is associated
with the 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 when the Link Type of the link
in the OSPFv2 Extended Link TLV containing this Sub-TLV is 1
(i.e., Point-to-Point connection to another router) or 2 (i.e.,
connection to Transit Network or say LAN).
DrEndBitPosition: A 2-octet field encoding the BitPosition of the
connection on the designated router (DR) end. This field
exists when the Link Type in the OSPFv2 Extended Link TLV
containing this Sub-TLV is 2 (i.e., Transit Network or LAN).
For the other value of the Link Type, this field MUST NOT
exist. The DrEndBitPosition 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].
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2.2. Routed and Localdecap BitPositions
A TLV, called Node BPs TLV, is defined within the body of the OSPF
Router Information (RI) Opaque Link State Advertisement (LSA)
[RFC7770]. The TLV contains Sub-TLVs. Two types of Sub-TLVs are
defined. One is for a Routed BitPosition and the other for a
Localdecap BitPosition.
The Node BPs 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Node BPs TLV
Type: TBD2 is to be assigned by IANA.
Length: Variable.
Sub-TLVs: Sub-TLVs containing the Routed BitPositions and Localdecap
BitPosition configured on a BFR.
The Routed-BP 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(8) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-domain-id | MT-ID | BAR | IPA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BitPosition | BFR-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Routed-BP Sub-TLV
Type: 1 is the type for routed BP.
Length: It is 8.
BitPosition: A 2-octet field encoding the BitPosition configured on
a BFR for a forward routed adjacency to a remote BFR.
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BFR-id: A 2-octet field encoding the BFR-id of the remote BFR.
sub-domain-id, MT-ID, BAR and IPA: They are the same as those
described in Section 2.1.
The Localdecap-BP 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 (T2) | Length(6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-domain-id | MT-ID | BAR | IPA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BitPosition |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Localdecap-BP Sub-TLV
Type: 2 is the type for localdecap BP.
Length: It is 6.
BitPosition: A 2-octet field encoding the localdecap BitPosition
configured on a BFR.
sub-domain-id, MT-ID, BAR and IPA: They are the same as those
described Section 2.1.
3. Security Considerations
Protocol extensions defined in this document do not affect the OSPF
security other than those as discussed in the Security Considerations
section of [RFC7684].
4. IANA Considerations
Under "OSPFv2 Extended Link TLV Sub-TLVs" registry as defined in
[RFC7684], IANA is requested to assign a new registry value for Link-
BP Sub-TLV as follows:
+==============+===================+=====================+
| Value | Description | reference |
+==============+===================+=====================+
| TBD1 (25) | Link-BP | This document |
+--------------+-------------------+---------------------+
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Under "OSPF Router Information (RI) TLVs" registry as defined in
[RFC7770], IANA is requested to assign a new registry value for Node
BPs TLV as follows:
+==============+===================+=====================+
| Value | Description | reference |
+==============+===================+=====================+
| TBD2 (21) | Node BPs | This document |
+--------------+-------------------+---------------------+
IANA is requested to create a new subregistry called the "OSPF Node
BPs Sub-TLVs" under the "Open Shortest Path First (OSPF) Parameters"
registry. The initial values are as follows:
+===========+===================+========================+
| Value | Description | reference |
+===========+===================+========================+
| 0 | Reserved | This document |
+-----------+-------------------+------------------------+
| 1 | Routed BP | This document |
+-----------+-------------------+------------------------+
| 2 | Localdecap BP | This document |
+-----------+-------------------+------------------------+
| 3 - 65535 | To be allocated in First Come First Served|
+-----------+-------------------+------------------------+
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>.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>.
[RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
Advertisement", RFC 7684, DOI 10.17487/RFC7684, November
2015, <https://www.rfc-editor.org/info/rfc7684>.
[RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
S. Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 7770, DOI 10.17487/RFC7770,
February 2016, <https://www.rfc-editor.org/info/rfc7770>.
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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-06, 9
March 2023, <https://datatracker.ietf.org/doc/html/draft-
chen-bier-te-lan-06>.
[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>.
[RFC8444] Psenak, P., Ed., Kumar, N., Wijnands, IJ., Dolganow, A.,
Przygienda, T., Zhang, J., and S. Aldrin, "OSPFv2
Extensions for Bit Index Explicit Replication (BIER)",
RFC 8444, DOI 10.17487/RFC8444, November 2018,
<https://www.rfc-editor.org/info/rfc8444>.
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
IBM Corporation
United States of America
Email: xufeng.liu.ietf@gmail.com
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