Appeal to the IESG's action for UPA draft----RE: [Lsr] Protocol Action: 'IGP Unreachable Prefix Announcement' to Proposed Standard (draft-ietf-lsr-igp-ureach-prefix-announce-11.txt) (Aijun Wang) - 2025-10-13
Appeal - 2025-10-13
From: "Aijun Wang" <wangaijun@tsinghua.org.cn>
Subject: [IAB] Appeal to the IESG's action for UPA draft----RE: [Lsr] Protocol Action: 'IGP Unreachable Prefix Announcement' to Proposed Standard (draft-ietf-lsr-igp-ureach-prefix-announce-11.txt)
Date: October 13, 2025 at 12:07:02 AM PDT
To: <iab@iab.org>
Cc: 'The IESG' <iesg@ietf.org>, rtg-ads@ietf.org, lsr-chairs@ietf.org, draft-ietf-lsr-igp-ureach-prefix-announce@ietf.org
Hi, IAB Chair:
Here I appeal to the decision of IESG's forwarding of the UPA draft.( https://datatracker.ietf.org/doc/draft-ietf-lsr-igp-ureach-prefix-announce/).
I am aware that the principle of IETF is rough consensus, but I don't know why such "rough consensus" principle produces again one contradictory standard.
The administration of routing area should be updated to rectify such trend.
Let's focus on the outstanding technical contradictory in this document:
The document proposes one mechanism that are CONSTRADICTORY to the OSPF base document RFC 2328.
Start of Logical Reasoning
Here is the procedure of the logical reasoning:
1) The document proposes to utilize the "LSInfinity" feature that is defined in RFC 2328 to signal UPA.
2) RFC 2328 states clearly that "LSA with LSInifinity metric" can't pass the ABR(.......“Else, if the routing table cost equals or exceeds the value LSInfinity, a summary-LSA cannot be generated for this route.......”)
3) The UPA signal then can't pass to the remote, non-neighbor area, which is the main scenario that the UPA proposal wants to solve.
The document states that it updates the behavior of ABR:
"OSPF ABRs or ASBRs MAY advertise received UPAs between connected areas or domains. When doing so, the original LSInfinity metric value in UPA MUST be preserved. The cost to reach the originator of the received UPA MUST NOT be considered when readvertising the UPA to connected areas"
But, because the UPA is NO DIFFERENT FROM “the LSA with LSInifinity metric", then, such declaration already update the behavior that are defined in the base OSPF RFC 2328.
But, the document doesn't declare it updates RFC 2328, then, it CONFLICTS with RFC 2328.
Even it adds declaration later it will update RFC 2328, it will lead to another issue-----the reachable prefix in one area will become unreachable in another area, and trigger the wrong action, and disrupt the network.
In conclusion, whether it updates RFC 2328, or keep to conflict with the RFC 2328, the UPA mechanism will not work properly, and will bring the chaos for the operation of network.
End of Logical Reasoning
During the IESG's review, I have raised such question, and Ketan has given some responses, but failed to answer my logical reasoning above.
Here I want the IAB, to let any expert from the authors, or the LSR chairs, or the routing ADs, or the IESG experts who have reviewed this document, and followed along the discussion of this draft, OR any other known routing expert, to analyze the above logic reasoning procedures, and give their analysis in systematic manner to points out which points in the above analysis can't stands.
Or else, please return the document to the LSR WG, and find one more reasonable solution instead.
The key mail exchange about this issues can refer to the following reference links.
Aijun Wang
China Telecom
[1]: Appeal to the IESG for the forwarding of UPA draft: https://mailarchive.ietf.org/arch/msg/lsr/DVgfKZS5hk8tHeO5n7CVK05ukcQ/
[2]: Response from the IESG's chair for [1]: https://mailarchive.ietf.org/arch/msg/lsr/XSGrydrEA0SOy9tSlDaNce4EyPc/
[3]: Response for the reply of IESG's response: https://mailarchive.ietf.org/arch/msg/lsr/drZyz2YIucydqXImG05C75APDZU/
[4]: Discussion with Ketan for the outstanding issue a): https://mailarchive.ietf.org/arch/msg/lsr/FHaXSSEMbSFUxRVdiBAAOEIeIy4/
-----Original Message-----
From: forwardingalgorithm@ietf.org [mailto:forwardingalgorithm@ietf.org] On Behalf Of The IESG
Sent: Friday, September 26, 2025 4:28 AM
To: IETF-Announce <ietf-announce@ietf.org>
Cc: The IESG <iesg@ietf.org>; draft-ietf-lsr-igp-ureach-prefix-announce@ietf.org; james.n.guichard@futurewei.com; lsr-chairs@ietf.org; lsr@ietf.org; rfc-editor@rfc-editor.org; yingzhen.ietf@gmail.com
Subject: [Lsr] Protocol Action: 'IGP Unreachable Prefix Announcement' to Proposed Standard (draft-ietf-lsr-igp-ureach-prefix-announce-11.txt)
The IESG has approved the following document:
- 'IGP Unreachable Prefix Announcement'
(draft-ietf-lsr-igp-ureach-prefix-announce-11.txt) as Proposed Standard
This document is the product of the Link State Routing Working Group.
The IESG contact persons are Gunter Van de Velde, Jim Guichard and Ketan Talaulikar.
A URL of this Internet-Draft is:
https://datatracker.ietf.org/doc/draft-ietf-lsr-igp-ureach-prefix-announce/
Technical Summary
Summarization is often used in multi-area or multi-domain networks to
improve network efficiency and scalability. With summarization in
place, there is a need to signal loss of reachability to an
individual prefix covered by the summary. This enables fast
convergence by steering traffic away from the node which owns the
prefix and is no longer reachable.
This document describes how to use the existing protocol mechanisms
in IS-IS and OSPF, together with the two new flags, to advertise such
prefix reachability loss.
Working Group Summary
Working group consensus to move this document forward. One participant felt strongly against moving the document forward on technical grounds. These were reviewed by the responsible AD, as well as the IESG during appeal, and found to have been adequately addressed by the working group and document authors. Other objections were also addressed and these are fully documented in the shepherd writeup.
Document Quality
Multiple vendor implementations. There are known implementations of the mechanism defined in this document.
Personnel
The Document Shepherd for this document is Yingzhen Qu. The Responsible
Area Director is Jim Guichard.