Re: [OSPF] Question about exiting graceful restart (Local Mode) for OSPFv3
"sujay gupta" <sujay.ietf@gmail.com> Sun, 11 November 2007 11:45 UTC
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Date: Sun, 11 Nov 2007 13:21:37 +0530
From: sujay gupta <sujay.ietf@gmail.com>
To: Adi Pasca <adi_pasca79@yahoo.com>
Subject: Re: [OSPF] Question about exiting graceful restart (Local Mode) for OSPFv3
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Hi Adi, IMHO Change in link preifx or change in network prefix should cause the Router A regenerate new LS updates.( as per the specs) If it has not changed the newly generated router and network lsa should be sufficient to build the graph post GR. -Sujay On 10/29/07, Adi Pasca <adi_pasca79@yahoo.com> wrote: > > Hi, > > I have one comment/question regarding the exit restart > procedure for Local Mode for OSPFv3 ( > > http://www.ietf.org/internet-drafts/draft-ietf-ospf-ospfv3-graceful-restart-07.txt > ) > > - in RFC3623, "Section 2.3 Actions on Exiting Graceful > Restart" it is said that: > > (...) > > 1) The router should reoriginate its router-LSAs > for all attached > areas in order to make sure they have the > correct contents. > > 2) The router should reoriginate network-LSAs on > all segments > where it is the Designated Router. > > (...) > > > >From what I have seen, the > draft-ietf-ospf-ospfv3-graceful-restart-07.txt doesn't > make any > update to the above section, but I was wondering if > this is enough in the case of OSPFv3 graceful restart > (because for OSPFv3 there are also the Link LSAs and > Intra-Area-Prefix LSAs which contribute > to the intra-area's topology description); > shouldn't the Link LSAs and the Intra-Area-Prefix LSAs > be reoriginated also ? > > > One scenario that could lead to neighbors' databases > being not synchronized after an restart is as follows: > > 1. We have two ospf routers (Router_A and Router_B) > having configured one ospf area, each having a single > interface into that area; > 2. Router_A is given a command to restart gracefully; > almost simultaneously (after Router_A transmits its > Grace LSA) Router_B's ospfv3 is disabled and then > enabled (or non-gracefully restarted), > so that it cannot act as helper. > 3. Hellos are received and the Database Exchange takes > place (with Router_A being in graceful restart, so not > originating any of its LSAs) > 4. After that (when exchange is done), Router_A > determines that it should exit restart due to > inconsistency > (RFC 3623: A special case of LSA inconsistency is > when Router X establishes an adjacency with router Y > and > doesn't receive an instance of its own pre-restart > router LSA.) > 5. When exiting restart, Router_A reoriginate its > Router LSA and, if it is the case, its Network LSA, so > Router_B receives those LSAs; but Router_B never > receives > Router_A's Link LSAs and Intra-Area-Prefix LSAs. > > Regards, > Adrian > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > > > _______________________________________________ > OSPF mailing list > OSPF@ietf.org > https://www1.ietf.org/mailman/listinfo/ospf >
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