Subject: RE: [Isis-wg] comment on draft-parker-short-isis-hold-times-00.t xt

From: Jeff Parker <[email-masked]>
Date: Wed, 28 Feb 2001 15:40:07 -0500

> As long as you generate LSP updates when the adjacency is dropped 
> quickly and you apply some sort of backoff interval when the 
> adjacency comes back, is there any reason that you can not generate 
> an LSP update immediately when adjacencies are lost (via L2 
> notification)?
> 
> Bora

and

> So long as you have a large minLSPgen timer, [when] ..
> two events occur over a short time span [you]...
> would have to wait 30 seconds to propagate the 
> second change....
> 
> Note that I am not in opposition to the faster convergence 
> concept - just want to be sure all aspects are addressed.
> 
> Les

Good points both.  I see the goals as

	o Fast Response to change
	o Stable Networks

which starts with a basic tension.  

The adjacency damping is really there to reduce the 
number of LSP re-generations.   Perhaps it would be 
better to focus on controling that directly.  

I think we still want to preserve the notion of "quick loss,
slow win", so that losing an adjacency would result in a quick
LSP regen, while addition of an adjacency could wait.  

We also want to preserve some overall rate limiting mechanism
on the frequence of LSP regeneration: perhaps an exponential
backoff that affects even the fast-twitch Adjacency-loss regen.

Perhaps we could take this off-list and come up with a proposal?

- jeff parker
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From: Alex Zinin <[email-masked]>
Date: Wed, 28 Feb 2001 16:58:57 -0800

A small comment here.
While we do want to exponentially (with a considerably
wide range of delay values) dampen interfaces and adjacencies,
LSP origination should still be paced with a constant max
rate even if the starting part of the delay curve goes
exponentially.

Alex.