draft-ietf-idr-eag-distribution-09.txt   draft-ietf-idr-eag-distribution-10.txt 
IDR Working Group Z. Wang IDR Working Group Z. Wang
Internet-Draft Q. Wu Internet-Draft Q. Wu
Intended status: Standards Track Huawei Intended status: Standards Track Huawei
Expires: April 20, 2020 J. Tantsura Expires: May 24, 2020 J. Tantsura
Apstra, Inc. Apstra, Inc.
October 18, 2019 K. Talaulikar
Cisco Systems
November 21, 2019
Distribution of MPLS-TE Extended admin Group Using BGP Distribution of MPLS-TE Extended admin Group Using BGP-LS
draft-ietf-idr-eag-distribution-09 draft-ietf-idr-eag-distribution-10
Abstract Abstract
As MPLS-TE network grows, administrative Groups advertised as a Administrative groups (commonly referred to as "colors" or "link
fixed-length 32-bit Bitmask is quite constraining. "Extended colors") are link attributes that are advertised by link state
Administrative Group" IGP TE extensions sub-TLV is introduced to protocols like IS-IS (Intermediate System to Intermediate System) and
provide for additional administrative groups (link colors) beyond the OSPF (Open Shortest Path First) and used for traffic engineering.
current limit of 32. This document describes extensions to BGP These administrative groups have initially been defined as a fixed-
protocol, that can be used to distribute extended administrative length 32-bit bitmask. As networks grew and more use-cases were
groups in MPLS-TE. 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. This document introduces extensions to
BGP-LS (Border Gateway Protocol Link-State) for advertisement of the
extended administrative groups.
Status of This Memo Status of This Memo
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provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. Carrying Extended Administrative Groups in BGP . . . . . . . 3 2. Advertising Extended Administrative Groups in BGP-LS . . . . 3
3.1. AG and EAG coexistence . . . . . . . . . . . . . . . . . 3 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
3.2. Desire for unadvertised EAG bits . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 4 6. Normative References . . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4
8. Normative References . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction 1. Introduction
MPLS-TE advertises 32 administrative groups (commonly referred to as Administrative groups (commonly referred to as "colors" or "link
"colors" or "link colors") using the Administrative Group sub-TLV of colors") are link attributes that are advertised by link state
the Link TLV defined in OSPFv2 (RFC3630), OSPFv3 (RFC5329) and ISIS protocols like IS-IS [RFC5305], OSPFv2 [RFC3630] and OSPFv3 [RFC5329]
(RFC5305). for traffic engineering use-cases. The BGP-LS advertisement is
encoded using the Administrative Group (color) TLV 1088 as defined in
[RFC7752].
As MPLS-TE network grows, administrative Groups advertised as a These administrative groups are defined as a fixed-length 32-bit
fixed-length 32-bit Bitmask is quite constraining. "Extended bitmask. As networks grew and more use-cases were introduced, the
Administrative Group" IGP TE extensions sub-TLV defined in [RFC7308] 32-bit length was found to be constraining and hence extended
is introduced to provide for additional administrative groups (link administrative groups (EAG) were introduced in the IS-IS and OSPFv2
colors) beyond the current limit of 32. link state routing protocols [RFC7308].
TThis document defines a new TLV to be carried within BGP-LS This document specifies extensions to BGP-LS for advertisement of the
attribute (defined in [I.D-ietf- idr-ls-distribution]) to distribute extended administrative groups.
extended administrative groups in MPLS-TE.
2. Requirements Language 1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Carrying Extended Administrative Groups in BGP 2. Advertising Extended Administrative Groups in BGP-LS
This document proposes one new BGP link attribute TLVs that can be This document defines extensions that enable BGP-LS speakers to
announced as attribute in the BGP-LS attribute (defined in [I.D-ietf- signal the EAG of links in a network to a BGP-LS consumer of network
idr-ls-distribution]) to distribute extended administrative groups. topology such as a centralized controller. The centralized
The extensions in this document build on the ones provided in BGP-LS controller can leverage this information in traffic engineering
[RFC7752] and BGP-4 [RFC4271]. 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.
BGP-LS attribute defined in [RFC7752] has nested TLVs which allow the EAG of a link is encoded in a new Link Attribute TLV [RFC7752] using
BGP-LS attribute to be readily extended. Link attribute TLVs defined the following format:
in section 3.2.2 of [I-D.ietf-idr-ls-distribution]are TLVs that may
be encoded in the BGP-LS attribute with a link NLRI. Each 'Link
Attribute' is a Type/Length/ Value (TLV) triplet formatted as defined
in Section 3.1 of [I-D.ietf-idr-ls-distribution].
This document proposes one new TLV as a link attribute: 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) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Value Figure 1: Extended Administrative Groups TLV Format
TBD1 Extended Administrative Group (EAG) Where:
The EAG TLV is used in addition to the Administrative Groups when a o Type: 1173
node wants to advertise more than 32 colors for a link. The EAG TLV
is optional. The format and semantics of the 'value' fields in EAG
TLVs correspond to the format and semantics of value fields in IGP
extension sub-TLVs, defined in [RFC7308].
+------------+---------------------+--------------+-----------------+ o Length: variable (MUST be multiple of 4); represents the total
| TLV Code | Description | IS-IS | Defined in: | length of the value field in octets.
| Point | | TLV/Sub-TLV | |
+------------+---------------------+--------------+-----------------+
| TBD1 | Extended | 22/14 | [RFC7308] |
| |Admininstrative Group| | |
+------------+---------------------+--------------+-----------------+
Table 1: 'EAG' Link Attribute TLV 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.
3.1. AG and EAG coexistence The EAG TLV is an optional TLV. The existing AG TLV 108 and the EAG
TLV introduced in this document MAY be advertised together. The
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].
Similar to section 2.3.1 of [RFC7308],if a BGP speaker advertises 3. IANA Considerations
both AG and EAG then AG and EAG should be dealt with in the same way
as AG and EAG carried in the Extended Administrative Group (EAG) sub-
TLV [RFC7308] for both OSPF [RFC3630] and ISIS [RFC5305].
3.2. Desire for unadvertised EAG bits 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.
Unlike AGs, EAGs are advertised as any non-zero-length-bit Bitmask. +------------+-------------------------------+-------------------+
the EAG length may be longer for some links than for others. Similar | Code Point | Description | IS-IS TLV/Sub-TLV |
to section 2.3.2 of [RFC7308], if a BGP peer wants to only use links +------------+-------------------------------+-------------------+
where the specific bits of an EAG is set to 1 but the specific bits | 1173 | Extended Administrative Group | 22/14 |
of this EAG is not advertised, then the implementation SHOULD process +------------+-------------------------------+-------------------+
these desire and unadvertised EAG bits in accordance with rule
defined in section 2.3.2 of [RFC7308].
4. Security Considerations 4. Security Considerations
This document does not introduce security issues beyond those The extensions in this document advertise same administrative group
discussed in [RFC7752] and [RFC4271]. information specified via [RFC7752] but as a larger/extended value
and hence does not introduce security issues beyond those discussed
5. IANA Considerations in [RFC7752].
This document requests assigning code-points from the registry "BGP-
LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute
TLVs" for the new Link Attribute TLVs defined in the table above:
6. Contributors
Ketan Talaulikar
Cisco Systems Inc.
Email: ketant@cisco.com
7. Acknowledgments 5. Acknowledgments
The authors gratefully acknowledge the review made by Eric Osborne. The authors gratefully acknowledge the review by Eric Osborne and Les
Ginsberg.
8. Normative References 6. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997. Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
[RFC3630] Katz, D., Yeung, D., and K. Kompella, "Traffic Engineering <https://www.rfc-editor.org/info/rfc2119>.
(TE) Extensions to OSPF Version 2", RFC 3630, September
2003.
[RFC4271] Rekhter, Y., "A Border Gateway Protocol 4 (BGP-4)", [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
RFC 4271, January 2006. (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 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, October 2008. Engineering", RFC 5305, DOI 10.17487/RFC5305, October
2008, <https://www.rfc-editor.org/info/rfc5305>.
[RFC7308] Osborne, E., "Extended Administrative Groups in MPLS-TE", [RFC5329] Ishiguro, K., Manral, V., Davey, A., and A. Lindem, Ed.,
ID RFC7308, July 2014. "Traffic Engineering Extensions to OSPF Version 3",
RFC 5329, DOI 10.17487/RFC5329, September 2008,
<https://www.rfc-editor.org/info/rfc5329>.
[RFC7752] Gredler, H., "North-Bound Distribution of Link-State and [RFC7308] Osborne, E., "Extended Administrative Groups in MPLS
TE Information using BGP", RFC 7752, March 2016. 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 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
Authors' Addresses Authors' Addresses
Zitao Wang Zitao Wang
Huawei Huawei
101 Software Avenue, Yuhua District 101 Software Avenue, Yuhua District
skipping to change at line 215 skipping to change at page 6, line 4
101 Software Avenue, Yuhua District 101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012 Nanjing, Jiangsu 210012
China China
Email: bill.wu@huawei.com Email: bill.wu@huawei.com
Jeff Tantsura Jeff Tantsura
Apstra, Inc. Apstra, Inc.
Email: jefftant.ietf@gmail.com Email: jefftant.ietf@gmail.com
Ketan Talaulikar
Cisco Systems
Email: ketant@cisco.com
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