IDR Working Group Z. Wang
Internet-Draft Q. Wu
Intended status: Standards Track Huawei
Expires: May 24, 2020 J. Tantsura
Apstra, Inc.
K. Talaulikar
Cisco Systems
November 21, 2019
Distribution of Traffic Engineering Extended Admin Groups using BGP-LS
draft-ietf-idr-eag-distribution-11
Abstract
Administrative groups (commonly referred to as "colors" or "link
colors") are link attributes that are advertised by link state
protocols like IS-IS (Intermediate System to Intermediate System) and
OSPF (Open Shortest Path First) and used for traffic engineering.
These administrative groups have initially been defined as a fixed-
length 32-bit bitmask. As networks grew and more use-cases were
introduced, the 32-bit length was found to be constraining and hence
extended administrative groups were introduced in the link state
protocols. The 32-bit administrative groups are already advertised
as link attributes in BGP-LS (Border Gateway Protocol Link-State).
This document defines extensions to BGP-LS for advertisement of the
extended administrative groups.
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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Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on May 24, 2020.
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Copyright Notice
Copyright (c) 2019 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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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Advertising Extended Administrative Groups in BGP-LS . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4
6. Normative References . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
Administrative groups (commonly referred to as "colors" or "link
colors") are link attributes that are advertised by link state
protocols like IS-IS [RFC5305], OSPFv2 [RFC3630] and OSPFv3 [RFC5329]
for traffic engineering use-cases. The BGP-LS advertisement is
encoded using the Administrative Group (color) TLV 1088 as defined in
[RFC7752].
These administrative groups are defined as a fixed-length 32-bit
bitmask. As networks grew and more use-cases were introduced, the
32-bit length was found to be constraining and hence extended
administrative groups (EAG) were introduced in the IS-IS and OSPFv2
link state routing protocols [RFC7308].
This document specifies extensions to BGP-LS for advertisement of the
extended administrative groups.
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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. Advertising Extended Administrative Groups in BGP-LS
This document defines extensions that enable BGP-LS speakers to
signal the EAG of links in a network to a BGP-LS consumer of network
topology such as a centralized controller. The centralized
controller can leverage this information in traffic engineering
computations and other use-cases. When a BGP-LS speaker is
originating the topology learnt via link-state routing protocols like
OSPF or IS-IS, the EAG information of the links is sourced from the
underlying extensions as defined in [RFC7308]. The BGP-LS speaker
may also advertise the EAG information for the local links of a node
when not running any link-state IGP protocol e.g. when running BGP as
the only routing protocol.
EAG of a link is encoded in a new Link Attribute TLV [RFC7752] using
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended Administrative Groups (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Extended Administrative Groups TLV Format
Where:
o Type: 1173
o Length: variable (MUST be multiple of 4); represents the total
length of the value field in octets.
o Value : one or more sets of 32-bit bitmasks that indicate the
administrative groups (colors) that are enable on the link when
those specific bits are set.
The EAG TLV is an optional TLV. The existing AG TLV 108 and the EAG
TLV defined in this document MAY be advertised together. The
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semantics of the EAG and the backward compatibility aspects of EAG
with respect to the AG are handled as described in the Backward
Compatibility section of [RFC7308].
3. IANA Considerations
This document requests assigning code-point from the registry "BGP-LS
Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute
TLVs" based on table below. Early allocation for these code-points
have been done by IANA.
+------------+-------------------------------+-------------------+
| Code Point | Description | IS-IS TLV/Sub-TLV |
+------------+-------------------------------+-------------------+
| 1173 | Extended Administrative Group | 22/14 |
+------------+-------------------------------+-------------------+
4. Security Considerations
The extensions in this document advertise same administrative group
information specified via [RFC7752] but as a larger/extended value
and hence does not introduce security issues beyond those discussed
in [RFC7752].
5. Acknowledgments
The authors gratefully acknowledge the review by Eric Osborne and Les
Ginsberg.
6. 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>.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630,
DOI 10.17487/RFC3630, September 2003,
<https://www.rfc-editor.org/info/rfc3630>.
[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>.
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[RFC5329] Ishiguro, K., Manral, V., Davey, A., and A. Lindem, Ed.,
"Traffic Engineering Extensions to OSPF Version 3",
RFC 5329, DOI 10.17487/RFC5329, September 2008,
<https://www.rfc-editor.org/info/rfc5329>.
[RFC7308] Osborne, E., "Extended Administrative Groups in MPLS
Traffic Engineering (MPLS-TE)", RFC 7308,
DOI 10.17487/RFC7308, July 2014,
<https://www.rfc-editor.org/info/rfc7308>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>.
[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>.
Authors' Addresses
Zitao Wang
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: wangzitao@huawei.com
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: bill.wu@huawei.com
Jeff Tantsura
Apstra, Inc.
Email: jefftant.ietf@gmail.com
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Ketan Talaulikar
Cisco Systems
Email: ketant@cisco.com
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