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 10:06:46 -0500

> I would second Dave here, keeping these timers on a per next 
> hop basis and then generating these interrupts when these 
> timers expire while doing line rate forwarding is a tad tricky.
> 
> On a SONET link, it is fairly easy to detect that your 
> neighbor has gone down and notify your peers. On an ethernet 
> I do recognize this gets harder, but can we make do with a 
> software based keep-alive mechanism that doesn't involve the 
> forwarding plane?
> 
> Regards
> 
> Bora

Bora -

While I don't want to conflate Radia's proposal with the draft, 
the draft tries to be clear in section 8.1 that anytime Level 2 
information tells us that a link is down, we should delete any
adjacencies on that link.  

Reacting to Physical Link failures is one of those things that 
I think everyone agrees is a Good Thing.   Van, Cengiz and 
company have just pointed out that sometimes we forget to
implement things that we all know are good.

The Hello PDUs act as the software based keep-alive mechanism 
that you mention.  There has been some interest expressed
in playing with lower TTLs in this mechanism: this draft is
trying to suggest a common format for such experiments. 

We return now to our regular bashing of the concept that
we can meet any schedules with deadlines under 30 seconds.

- jeff parker
- Entropy ain't what it used to be

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From: Bora Akyol <[email-masked]>
Date: Wed, 28 Feb 2001 09:25:11 -0800

Following up on this thread, on BGP the recommended behavior is to 
not use a timer for withdrawals when adjacencies fail, can one 
utilize a similar behavior and immediately generate and distribute 
updated LSPs when L2 link is lost?

Bora