Re: Waiting State Question

Mukul Goyal <mukul@UWM.EDU> Thu, 19 May 2005 18:14 UTC

Received: from cherry.ease.lsoft.com (cherry.ease.lsoft.com [209.119.0.109]) by ietf.org (8.9.1a/8.9.1a) with ESMTP id OAA01913 for <ospf-archive@LISTS.IETF.ORG>; Thu, 19 May 2005 14:14:27 -0400 (EDT)
Received: from vms.dc.lsoft.com (209.119.0.2) by cherry.ease.lsoft.com (LSMTP for Digital Unix v1.1b) with SMTP id <18.01050038@cherry.ease.lsoft.com>; Thu, 19 May 2005 14:14:26 -0400
Received: by PEACH.EASE.LSOFT.COM (LISTSERV-TCP/IP release 14.3) with spool id 71662314 for OSPF@PEACH.EASE.LSOFT.COM; Thu, 19 May 2005 14:14:24 -0400
Received: from 129.89.169.226 by WALNUT.EASE.LSOFT.COM (SMTPL release 1.0l) with TCP; Thu, 19 May 2005 14:14:24 -0400
Received: from mail04.imt.uwm.edu (mail04.imt.uwm.edu [129.89.7.46]) by batch3.csd.uwm.edu (8.12.10/8.12.6) with ESMTP id j4JIENDD000161 for <OSPF@PEACH.EASE.LSOFT.COM>; Thu, 19 May 2005 13:14:23 -0500 (CDT)
Received: from localhost (pm02.imt.uwm.edu [129.89.7.62]) by mail04.imt.uwm.edu (8.12.10/8.12.5) with ESMTP id j4JIEMrW009101 for <OSPF@PEACH.EASE.LSOFT.COM>; Thu, 19 May 2005 13:14:23 -0500
Received: from adsl-68-248-231-128.dsl.milwwi.ameritech.net (adsl-68-248-231-128.dsl.milwwi.ameritech.net [68.248.231.128]) by panthermail.uwm.edu (IMP) with HTTP for <mukul@localhost>; Thu, 19 May 2005 13:14:22 -0500
References: <20050519122021.40976.qmail@web25301.mail.ukl.yahoo.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 8bit
User-Agent: PantherMail 3.2.9-cvs
X-Originating-IP: 68.248.231.128
X-Virus-Scanned: by amavisd-new
X-Spam-Status: No, hits=-48.165 required=5 tests=MAILTO_TO_SPAM_ADDR,NO_REAL_NAME,UWM_DOMAIN_MESSAGE_1
X-Scanned-By: MIMEDefang 2.51 on 129.89.7.46
Message-ID: <1116526462.428cd77ee421b@panthermail.uwm.edu>
Date: Thu, 19 May 2005 13:14:22 -0500
Reply-To: Mailing List <OSPF@PEACH.EASE.LSOFT.COM>
Sender: Mailing List <OSPF@PEACH.EASE.LSOFT.COM>
From: Mukul Goyal <mukul@UWM.EDU>
Subject: Re: Waiting State Question
To: OSPF@PEACH.EASE.LSOFT.COM
In-Reply-To: <20050519122021.40976.qmail@web25301.mail.ukl.yahoo.com>
Precedence: list
Content-Transfer-Encoding: 8bit

My guess is that if an interface comes out of the waiting state on receiving a
Hello from DR (without having received a Hello from BDR), it may elect itself
as BDR. This way many routers may elect themselves as BDR. Now all these BDR
claimants (except one) will ultimately take their claims to BDRship back but in
the process each router on the LAN may have to do several DR elections.

Here is a paper we wrote recently that may shed further light on this:
http://cs.uwm.edu/~mukul/ospflan.pdf

Thanks,
Mukul

Quoting John Smith <jsmith4112003@YAHOO.CO.UK>:

> Hi,
>
> When a router comes up it starts the Wait Timer before it elects the DR/BDR.
> It either
> waits for the Wait Timer to expire or it waits for a router declaring itself
> as the BDR
> before it decides that it needs to get out of the 'Waiting' state (it does
> this by
> generating the Backupseen event).
>
> My question is why does it wait only for the BDR? Why not the DR? It can when
> it recieves
> a HELLO from the DR know that their exists a DR and a BDR. Why not then get
> out of the
> 'Waiting' state?
>
> Thanks,
> John
>
> Send instant messages to your online friends http://uk.messenger.yahoo.com
>