[ntp:questions] very slow convergence of ntp to correct time.

Eric nospam-01 at jensenresearch.com
Mon Jan 28 20:53:40 UTC 2008


Hi Rick - 

You are probably right about the MAC cache miss not affecting timing.  You
are the resident switch guru here. 

Of course, different manufacturers may have different methods of detecting
the cache miss and recovering from that, so it would be hard to eliminate
that effect from consideration entirely.  It's the smallest effect of all
the ones I've dealt with.

- Eric

On Mon, 28 Jan 2008 20:44:39 +0000 (UTC), Rick Jones <rick.jones2 at hp.com>
wrote for the entire planet to see:

>Eric <nospam-01 at jensenresearch.com> wrote:
>> Then there is the MAC cache in your switches, which generally purge
>> after 1-5 minutes.  This can often be adjusted higher, but that can
>> sometimes cause issues for others when they are reconfiguring part
>> of the network.
>
>I suppose if STP gets involved, but just on its own, the forwarding
>table in a switch being aged should only mean that the next frame to
>that MAC will go out all (enabled) ports on the switch until that MAC
>is seen again as a source.  That shouldn't affect timing really.
>
>rick jones




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