Re: Single subnet

Dave Katz <> Mon, 21 May 1990 13:42 UTC

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Received: Mon, 21 May 90 08:41:20 EST by (5.59/1.6)
Date: Mon, 21 May 90 08:41:20 EST
From: Dave Katz <>
Message-Id: <>
Subject: Re: Single subnet
Status: O

>> I think that the suggested ES hello timer sent by ISs should be cranked
>> way down (from 600 seconds to 20 or something..).  
>It might be prudent to be conservative with such timers.  

It's not as bad as it sounds;  ES Hellos are only received by ISs (assuming,
of course, that our vendors have implemented selective multicast reception).
With 1000 MACs and a 20 second timeout value, it translates to 50 fps for
the IS (which hopefully is capable of forwarding three orders of magnitude
more than that...).  Of course, these things may tend to synchronize; ES-IS
doesn't explicitly require jitter to be added (tho IS-IS does).
It's tough to avoid route flaps when *any* medium is saturated;  things
are surely broken in that case, and routing will be only part of it.