Advertising Layer 2 Bundle Member Link Attributes in IS-IS
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From: The IESG <email@example.com> To: IETF-Announce <firstname.lastname@example.org> Cc: The IESG <email@example.com>, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com Subject: Protocol Action: 'Advertising L2 Bundle Member Link Attributes in IS-IS' to Proposed Standard (draft-ietf-isis-l2bundles-07.txt) The IESG has approved the following document: - 'Advertising L2 Bundle Member Link Attributes in IS-IS' (draft-ietf-isis-l2bundles-07.txt) as Proposed Standard This document is the product of the IS-IS for IP Internets Working Group. The IESG contact persons are Alvaro Retana, Alia Atlas and Deborah Brungard. A URL of this Internet Draft is: https://datatracker.ietf.org/doc/draft-ietf-isis-l2bundles/
Technical Summary There are deployments where the Layer 3 interface on which IS-IS operates is a Layer 2 interface bundle. Existing IS-IS advertisements only support advertising link attributes of the Layer 3 interface. If entities external to IS-IS wish to control traffic flows on the individual physical links which comprise the Layer 2 interface bundle link attribute information about the bundle members is required. The extension in this document are mostly used for: 1) telemetry applications which build segment-routing stacks such that child-links of a bundle can get probed. 2) TE to manage the load on child links if there is an imbalance. Working Group Summary There was some controversy mostly triggered by network operators that the use-cases are not clear and wether IS-IS is the correct place for these extensions. BGP-LS was suggested as an alternative, mostly because BGP-LS is a strict northbound protocol and this would be the precedent-case for a pure-northbound protocol (= no receive side logic) in IS-IS. Alia raised awareness in OSPF, IDR, and RTGWG during the IETF Last Call to see if there were any concerns about this technical path forward and had a response that this direction can work for OSPF as well. Given the implications for an l2bundle being an IEEE Link Aggregate Group (LAG), Alia also raised awareness on the ieee-ietf- coord about the IETF LC, but without any response. While the draft shepherd clearly would prefer a different technical solution, there was clear WG consensus to publish and no discussion or disagreement at IETF 98. Document Quality There is one implementation for Cisco IOS-XR. At IETF 98 ISIS WG, when this draft was discussed, Les mentioned that Cisco is awaiting the IANA code-point to ship this feature. Personnel Hannes Gredler (isis-wg co-chair) is the Document Shepherd. Alia Atlas is the AD.