[OSPF] Question about exiting graceful restart (Local Mode) for OSPFv3
Adi Pasca <adi_pasca79@yahoo.com> Mon, 29 October 2007 13:17 UTC
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Date: Mon, 29 Oct 2007 06:17:08 -0700
From: Adi Pasca <adi_pasca79@yahoo.com>
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Subject: [OSPF] Question about exiting graceful restart (Local Mode) for OSPFv3
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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