[OSPF] Question about exiting graceful restart (Local Mode) for OSPFv3

Adi Pasca <adi_pasca79@yahoo.com> Mon, 29 October 2007 13:17 UTC

Return-path: <ospf-bounces@ietf.org>
Received: from [127.0.0.1] (helo=stiedprmman1.va.neustar.com) by megatron.ietf.org with esmtp (Exim 4.43) id 1ImUUk-0003jq-Lv; Mon, 29 Oct 2007 09:17:30 -0400
Received: from [10.91.34.44] (helo=ietf-mx.ietf.org) by megatron.ietf.org with esmtp (Exim 4.43) id 1ImUUk-0003jl-9a for ospf@ietf.org; Mon, 29 Oct 2007 09:17:30 -0400
Received: from n8.bullet.re3.yahoo.com ([68.142.237.93]) by ietf-mx.ietf.org with smtp (Exim 4.43) id 1ImUUe-00061A-4C for ospf@ietf.org; Mon, 29 Oct 2007 09:17:30 -0400
Received: from [68.142.230.29] by n8.bullet.re3.yahoo.com with NNFMP; 29 Oct 2007 13:17:09 -0000
Received: from [66.196.101.133] by t2.bullet.re2.yahoo.com with NNFMP; 29 Oct 2007 13:17:09 -0000
Received: from [127.0.0.1] by rrr4.mail.re1.yahoo.com with NNFMP; 29 Oct 2007 13:17:08 -0000
X-Yahoo-Newman-Property: ymail-3
X-Yahoo-Newman-Id: 987371.48808.bm@rrr4.mail.re1.yahoo.com
Received: (qmail 93318 invoked by uid 60001); 29 Oct 2007 13:17:08 -0000
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:Date:From:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-ID; b=FHhkA9OGrH2ULXTwOR+oJA3g0XJ/iRpZryN0gkGoZLiGnG+CgBvf5vLlOzAut4oz+grGtqmxFyXl0Ez8ZLQsceub8dGDxeL/7EpN+AxXH4ah02aXXu0DVqLNXQYKTMubpSE709hV8VksUE26c0b8wdW9oHSFm+5k2DJM01npLX8=;
X-YMail-OSG: XoTREI0VM1n219jeRJUXT958FnsNCps.25t0sscwYEGSXe5Xi7.gUddS_7MDwzL2vQ--
Received: from [80.96.82.125] by web57402.mail.re1.yahoo.com via HTTP; Mon, 29 Oct 2007 06:17:08 PDT
Date: Mon, 29 Oct 2007 06:17:08 -0700
From: Adi Pasca <adi_pasca79@yahoo.com>
To: ospf@ietf.org
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 8bit
Message-ID: <880208.89146.qm@web57402.mail.re1.yahoo.com>
X-Spam-Score: 0.0 (/)
X-Scan-Signature: fb6060cb60c0cea16e3f7219e40a0a81
Subject: [OSPF] Question about exiting graceful restart (Local Mode) for OSPFv3
X-BeenThere: ospf@ietf.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: The Official IETF OSPG WG Mailing List <ospf.ietf.org>
List-Unsubscribe: <https://www1.ietf.org/mailman/listinfo/ospf>, <mailto:ospf-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www1.ietf.org/pipermail/ospf>
List-Post: <mailto:ospf@ietf.org>
List-Help: <mailto:ospf-request@ietf.org?subject=help>
List-Subscribe: <https://www1.ietf.org/mailman/listinfo/ospf>, <mailto:ospf-request@ietf.org?subject=subscribe>
Errors-To: ospf-bounces@ietf.org

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