IDR Working Group Z. Wang Internet-Draft Q. Wu Intended status: Standards Track Huawei Expires: August 21, 2021 J. Tantsura Juniper Networks K. Talaulikar Cisco Systems February 17, 2021 Distribution of Traffic Engineering Extended Admin Groups using BGP-LS draft-ietf-idr-eag-distribution-14 Abstract Administrative groups are link attributes (commonly referred to as "colors" or "link colors") advertised by link state protocols (e.g. ISIS or OSPF) and used for traffic engineering. These administrative groups were initially defined as 32 bit masks. As network usage grew, these 32 bit masks were found to constrain traffic engineering. Therefore, link state protocols (ISIS, OSPF) were expanded to advertise a variable length administrative group.This document defines an extension to BGP-LS for advertisement of extended administrative groups (EAGs) to allow to support a number of administrative groups greater than 32, as defined in [RFC7308]. 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 August 21, 2021. Copyright Notice Copyright (c) 2021 IETF Trust and the persons identified as the document authors. All rights reserved. Wang, et al. Expires August 21, 2021 [Page 1] Internet-Draft Extended admin Group February 2021 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 and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 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 of the originally defined (non-extended) administrative groups 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 an extension to BGP-LS for advertisement of the extended administrative groups. 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. Wang, et al. Expires August 21, 2021 [Page 2] Internet-Draft Extended admin Group February 2021 2. Advertising Extended Administrative Groups in BGP-LS This document defines an extension 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. The 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 length which represents the total length of the value field. The length value must MUST be multiple of 4. If the length is not a multiple of 4, the TLV must be considered malformed. 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 originally defined AG TLV 1108 and the EAG TLV 1173 defined 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], namely - If a node advertises both AG and EAG, then the first 32 bits of the EAG MUST be identical to the advertised AG. Wang, et al. Expires August 21, 2021 [Page 3] Internet-Draft Extended admin Group February 2021 3. IANA Considerations This document requests assigning a 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] and [I-D.ietf-idr-rfc7752bis]. 5. Acknowledgments The authors gratefully acknowledge the review by Eric Osborne and Les Ginsberg. 6. Normative References [I-D.ietf-idr-rfc7752bis] Talaulikar, K., "Distribution of Link-State and Traffic Engineering Information Using BGP", draft-ietf-idr- rfc7752bis-05 (work in progress), November 2020. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630, DOI 10.17487/RFC3630, September 2003, . [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, DOI 10.17487/RFC5305, October 2008, . Wang, et al. Expires August 21, 2021 [Page 4] Internet-Draft Extended admin Group February 2021 [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, . [RFC7308] Osborne, E., "Extended Administrative Groups in MPLS Traffic Engineering (MPLS-TE)", RFC 7308, DOI 10.17487/RFC7308, July 2014, . [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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 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 Juniper Networks Email: jefftant.ietf@gmail.com Wang, et al. Expires August 21, 2021 [Page 5] Internet-Draft Extended admin Group February 2021 Ketan Talaulikar Cisco Systems Email: ketant@cisco.com Wang, et al. Expires August 21, 2021 [Page 6]