Subject: Re: DROther/BDR graceful restart question

From: "Kandula, Ramesh" <[email-masked]>
Date: Mon, 13 Feb 2006 10:48:01 -1000

Hi Acee/Ashok,

That makes more sense. Thanks for clarifying this.

thanks
ramesh

-----Original Message-----
From: Acee Lindem [mailto:[email-masked]]
Sent: Friday, February 10, 2006 6:39 AM
To: [email-masked]
Subject: Re: DROther/BDR graceful restart question

Hi Ramesh,

Ramesh Kandula wrote:

>Hi All,
>
>Suppose a DROther router restarts gracefully on a broadcast network. 
>Before restart it has adjacencies with DR and BDR. According to clause in
> 
>2.2.1 (RFC 3623), it is supposed to wait till it forms adjacencies with 
>
>BDR and DR before exiting restart mode.
>
>However there is no way for it to determine who the BDR was before restar
>t 
>using the pre-restart router lsa (and/or pre-restart network lsa). Or am 
>I 
>missing something? Actually why is it necessary to wait (i.e for exiting 
>
>restart mode) till it forms an adjaceny with BDR? Isn't it enough for it 
>
>wait till it forms an adjacency with DR?
>  
>
You are correct. Only the DR adjacency needs to be reformed. We'll 
clarify if we ever respin
this RFC. The key point is that your pre-restart LSAs must match your 
current state  prior  to
existing graceful restart normally.

Thanks,
Acee

>A similar issue arises with BDR restart as well. According to the same 
>
>clause it is supposed to wait till it forms adjacencies with all the 
>routers on the network. However it has no way of determining that it was 
>
>the BDR using just the pre-restart lsas.
>
>Thanks,
>Ramesh
>
>  
>