RFC 9104

Distribution of Traffic Engineering Extended Administrative Groups Using the Border Gateway Protocol - Link State (BGP-LS)

📅 published August 2021, from ietf

RFC 9104 🎀

okay bestie, RFC 9104 is giving Standards Track energy 💅 It was published in August 2021 and its ISSN is 2070-1721 ✨ The authors are J. Tantsura from Microsoft, Z. Wang, Q. Wu from Huawei, and K. Talaulikar from Cisco Systems 👑 The title block doesn't list anything it obsoletes or updates, so this one is a standalone spec 🦋

Distribution of Traffic Engineering Extended Administrative Groups Using the Border Gateway Protocol - Link State (BGP-LS) 🌈

Abstract ✨

so the big idea is that administrative groups are link attributes used for traffic engineering 🚗💨 This doc adds an extension to the Border Gateway Protocol - Link State (BGP-LS) so extended administrative groups (EAGs) can be advertised 🔥

Status of This Memo 📜

this is an Internet Standards Track document 💖 It's a product of the Internet Engineering Task Force (IETF) and it represents the consensus of the IETF community. It got public review and was approved for publication by the Internet Engineering Steering Group (IESG) 🫶 For more on Internet Standards, check Section 2 of RFC 7841 🌸

for the current status, errata, and how to send feedback, go to https://www.rfc-editor.org/info/rfc9104 ✨

Copyright (c) 2021 IETF Trust and the persons identified as the document authors. All rights reserved 💜 This doc is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) as they were on the publication date. Read those carefully because they spell out your rights and restrictions 📖 Code Components pulled from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions, and they come without warranty as described in the Simplified BSD License 🎀

Table of Contents 🧚

1.  Introduction
  1.1.  Requirements Language
2.  Advertising Extended Administrative Groups in BGP-LS
3.  IANA Considerations
4.  Manageability Considerations
5.  Security Considerations
6.  References
  6.1.  Normative References
  6.2.  Informative References
Acknowledgments
Authors' Addresses

1. Introduction ✨

okay so administrative groups (aka "colors" or "link colors") are link attributes that link-state protocols advertise, like IS-IS [RFC1195], OSPFv2 [RFC2328], and OSPFv3 [RFC5340] 🦋 BGP-LS already advertises the original, non-extended administrative groups using the Administrative Group (color) TLV 1088, as defined in [RFC7752] 💅

these groups are a fixed-length 32-bit bitmask 🍓 As networks got bigger and more use cases showed up, 32 bits started feeling way too tight, so extended administrative groups (EAGs) were introduced in [RFC7308] 🚀

the EAG TLV (Section 2) is not a replacement for the Administrative Group (color) TLV 🙈 As [RFC7308] explains, both values can coexist 🫶 Specifying how the BGP-LS consumer behaves is out of scope for this doc [RFC7752] 💀

so this document is about the extension to BGP-LS that advertises 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" are interpreted as described in BCP 14 [RFC2119] [RFC8174] only when they show up in all capitals, exactly like this 💜 So if you see them in lowercase, they're just regular words, no drama 🌈

2. Advertising Extended Administrative Groups in BGP-LS 💅

this is where the magic happens ✨ The extension lets BGP-LS speakers signal the EAG of links in a network to a BGP-LS consumer of network topology, like a centralized controller 👑 That controller can use the info in traffic engineering computations and other use cases 🔥 When a BGP-LS speaker originates topology learned through link-state routing protocols like OSPF or IS-IS, the EAG info of the links comes from the underlying extensions defined in [RFC7308] 🦋

the EAG of a link gets encoded in a new Link Attribute TLV [RFC7752] using this 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 Group (variable)                  //
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          Figure 1: Extended Administrative Group TLV Format

here's the breakdown, bestie 🧚

  • Type: 1173
  • Length: variable length that's the total length of the value field in octets 🍓 The length value MUST be a multiple of 4. If the length is not a multiple of 4, the TLV MUST be considered malformed 🙈
  • Value: one or more sets of 32-bit bitmasks that show which administrative groups (colors) are enabled on the link when those specific bits are set 🌸

that's the whole format, ily 🌈✨

6.2. Informative References ✨

okay so these are the bonus reads 📚 the stuff that's useful background but not required to implement the spec. the whole squad, from the old-school IS-IS and OSPF crew to the BGP security nerds and the KARP design guide people 🦋

Acknowledgments 🫶

the authors wanna give a huge shoutout to Eric Osborne, Les Ginsberg, Tim Chown, Ben Niven-Jenkins, and Alvaro Retana for their reviews and valuable comments. literally the MVPs 👑

Authors' Addresses 💌

the people who wrote this thing, and how to reach them 💜

Jeff Tantsura
Microsoft

Email: jefftant.ietf@gmail.com


Zitao Wang
Huawei
Yuhua District
101 Software Avenue
Nanjing
Jiangsu, 210012
China

Email: wangzitao@huawei.com


Qin Wu
Huawei
Yuhua District
101 Software Avenue
Nanjing
Jiangsu, 210012
China

Email: bill.wu@huawei.com


Ketan Talaulikar
Cisco Systems

Email: ketant@cisco.com
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