On 10/06/2025 08:56, Aijun Wang wrote:
The corresponding section is contrary to the guideline in RFC2328:
"Else, if the routing table cost equals or exceeds the value LSInfinity, a
summary-LSA cannot be generated for this route."
we are updating that behavior, that is the purpose of the new RFCs,
isn't it?
Peter
-----Original Message-----
From: Peter Psenak [mailto:ppse...@cisco.com]
Sent: Tuesday, June 10, 2025 2:14 PM
To: Aijun Wang <wangai...@tsinghua.org.cn>; 'James Guichard'
<james.n.guich...@futurewei.com>
Cc: lsr@ietf.org
Subject: Re: [Lsr] One simple example that can prove current UPA don't
work-----RE: I-D Action: draft-ietf-lsr-igp-ureach-prefix-announce-08.txt
On 10/06/2025 02:59, Aijun Wang wrote:
Hi, Jim and All:
Here is another simple example that can prove current UPA don't work.
Let's image one normal topology:
PE1(area 1)----ABR1---P2(area 0)----ABR2---PE2(area 2)
When one prefix P0 on PE2 in area 2 became unreachable, according to the
current procedure, ABR2 will generate the UPA signal.
The UPA signal will be flooding within area 0.
But such UPA signal can't pass ABR1, then PE1 in another area can't get the
unreachable information.
above is not correct, please read the UPA draft:
https://datatracker.ietf.org/doc/html/draft-ietf-lsr-igp-ureach-prefix-announce-08#section-4.2
Peter
PE1 can't do any switchover action based on the expected UPA signal.
Current UPA proposal is broken in cross-area scenario.
Best Regards
Aijun Wang
China Telecom
-----Original Message-----
From: forwardingalgori...@ietf.org [mailto:forwardingalgori...@ietf.org] On
Behalf Of internet-dra...@ietf.org
Sent: Thursday, June 5, 2025 3:46 PM
To: i-d-annou...@ietf.org
Cc: lsr@ietf.org
Subject: [Lsr] I-D Action: draft-ietf-lsr-igp-ureach-prefix-announce-08.txt
Internet-Draft draft-ietf-lsr-igp-ureach-prefix-announce-08.txt is now
available. It is a work item of the Link State Routing (LSR) WG of the IETF.
Title: IGP Unreachable Prefix Announcement
Authors: Peter Psenak
Clarence Filsfils
Daniel Voyer
Shraddha Hegde
Gyan Mishra
Name: draft-ietf-lsr-igp-ureach-prefix-announce-08.txt
Pages: 15
Dates: 2025-06-05
Abstract:
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.
The IETF datatracker status page for this Internet-Draft is:
https://datatracker.ietf.org/doc/draft-ietf-lsr-igp-ureach-prefix-announce/
There is also an HTMLized version available at:
https://datatracker.ietf.org/doc/html/draft-ietf-lsr-igp-ureach-prefix-announce-08
A diff from the previous version is available at:
https://author-tools.ietf.org/iddiff?url2=draft-ietf-lsr-igp-ureach-prefix-announce-08
Internet-Drafts are also available by rsync at:
rsync.ietf.org::internet-drafts
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