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."
-----Original Message----- From: Peter Psenak [mailto:[email protected]] Sent: Tuesday, June 10, 2025 2:14 PM To: Aijun Wang <[email protected]>; 'James Guichard' <[email protected]> Cc: [email protected] 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: [email protected] [mailto:[email protected]] On > Behalf Of [email protected] > Sent: Thursday, June 5, 2025 3:46 PM > To: [email protected] > Cc: [email protected] > 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 > > > _______________________________________________ > Lsr mailing list -- [email protected] > To unsubscribe send an email to [email protected] > > _______________________________________________ > Lsr mailing list -- [email protected] > To unsubscribe send an email to [email protected] > _______________________________________________ Lsr mailing list -- [email protected] To unsubscribe send an email to [email protected]
