Subject: Re: [Isis-wg] operational problem might be solved by somehowextending current IS-IS

From: [email-masked]
Date: Fri, 17 Sep 2010 08:19:30 +0200

> On Sep 16, 2010, at 23:50 , Tony Li wrote:
>> I believe several folks have already stepped up to spec it.  However, I think the bigger issue is one of backward compatibility.   It's not obvious how to introduce this without creating forwarding loops.
>> 
> 
> _If_ current implementations permit (will not balk in the presence of) non-zero metric from pseudo-node to a node, then DIS setting reverse metric based on presence of 'reverse metric' TLV seems like a safe bet - only the router that wants to have non-zero reverse metric and DIS must support the feature, all other routers on the network can keep running old code and still select correct (consistent) best path. It would be perhaps useful to run quick poll among implementors whether or not their particular implementation (in current state) will allow non-zero metric in pseudo-node LSP.
> 
> /iLya

Also think this is better way, with DIS preempting, what if you have multiple nodes need to be taking out of service?

Cheers

Guan