Subject: Re: [rbridge] [Pppext] proposed TRILL IS-IS System ID text

From: Anoop Ghanwani <[email-masked]>
Date: Fri, 4 Feb 2011 17:01:35 -0800

On Thu, Jan 27, 2011 at 12:34 PM, James Carlson
<[email-masked]> wrote:

> At a minimum, I want to hear from IS-IS and TRILL experts before I go
> ahead with proposing any new random-number-based System ID mechanism.
> If they sign on, then I'll go ahead with it.
>
> But my off-the-cuff guess is that they'll have objections, and more
> objections probably aren't helpful in getting to consensus.

Coming from the TRILL part of the world, I don't think this is a problem
that needs to be addressed in this draft.  Generating a unique System ID
for IS-IS is an IS-IS problem, and as such should be addressed in the IS-IS
working group.

Anoop
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From: mike shand <[email-masked]>
Date: Mon, 07 Feb 2011 15:57:17 +0000

As far as IS-IS is concerned, the requirement is that the system ID 
must be unique within the routing domain (level 1 or level 2). IS-IS 
does not mandate HOW this unique system ID is obtained. Certainly, using 
a MAC address can be a good source of such unique IDs if you have 
confidence that they truly are unique. In a certain implementation from 
the early days, the system board contained a "MAC address" chip which 
was guaranteed to be unique (wrt to other such chips from the same 
manufacturer) and was used to generate the system ID even when there 
were no Ethernet cards installed.

But as has been pointed out, this is really left to the 
implementation/operator to ensure.

The consequence of having duplicate addresses is that LSP sequence 
numbers begin counting up, and generating network management events each 
time they do so. Most implementations have a means of flashing in big 
red letters that something is misconfigured.

     Mike