[12440] in North American Network Operators' Group
Re: I found the missing 30 milliseconds!
daemon@ATHENA.MIT.EDU (Jay R. Ashworth)
Tue Sep 16 18:07:35 1997
Date: Tue, 16 Sep 1997 17:46:26 -0400
From: "Jay R. Ashworth" <jra@scfn.thpl.lib.fl.us>
To: "Kent W. England" <kwe@geo.net>
Cc: nanog@merit.edu
In-Reply-To: <3.0.2.32.19970916130153.0071d3a0@zeus.geo.net>; from "Kent W. England" <kwe@geo.net> on Tue, Sep 16, 1997 at 01:01:53PM -0700
On Tue, Sep 16, 1997 at 01:01:53PM -0700, Kent W. England wrote a
treatise which identified the Rose Mary Woods of the Internet, or so he
thought...:
> You can't send a packet out an interface until the entire packet has been
> received on the incoming interface. Now if we assume 1500 byte packets (the
> new de facto MTU on all modern Internet backbones) and DS-3 pipes, then it
> takes about 250 microseconds to buffer the pkt on each hop. Since the US
> internet backbone from coast to coast is about 120 hops, there's your 30
> milliseconds and Bob's your uncle.
>
> Did I do the arithmetic right?
I think you did the math right...
but isn't that what "cut-through" switching is all about? Sending the
packet out before you're done getting it in?
Cheers,
-- jra
--
Jay R. Ashworth jra@baylink.com
Member of the Technical Staff Unsolicited Commercial Emailers Sued
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