Updating RFC2328 is possible, but based on LSInfinity is not appropriate: 1) Allowing the pass of LSA with Infinity metric will make some reachable prefix unreachable(according to the logic of current UPA proposal). 2) Do not allowing the pass of LSA with Infinity metric will make the UPA don't work(according to the procedure defined in RFC 2328).
Then, the solution based on the LSInfinity feature will be in dilemma states. Anyway, the document isn't ready for publication. Best Regards Aijun Wang China Telecom -----Original Message----- From: Peter Psenak [mailto:[email protected]] Sent: Tuesday, June 10, 2025 3:07 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 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:[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-ann >> ounce/ >> >> There is also an HTMLized version available at: >> https://datatracker.ietf.org/doc/html/draft-ietf-lsr-igp-ureach-prefi >> x-announce-08 >> >> A diff from the previous version is available at: >> https://author-tools.ietf.org/iddiff?url2=draft-ietf-lsr-igp-ureach-p >> refix-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]
