Exchanges that matter...

Subject: Re: Exchanges that matter...
Date: Fri, 29 Nov 1996 11:02:24 -0800
From: Paul A Vixie <>
... and they aren't subject to ATM's cell tax ...

I am surprised, (well, maybe not), that you aren't concerned about
the excessive overhead present in FDDI networks...


Date: Tue, 23 Jul 1996 14:28:27 -0400
From: Paul Ferguson <>
Recall Jerry Scharf's numbers; they're indicative of the issue.
HDLC framing bytes = 3080633605 HDLC efficiency = 97.72
ATM framing bytes = 3644304857 ATM efficiency = 82.61
ATM w/snap framing bytes = 3862101043 ATM w/snap efficiency = 77.95

At a certain point, some of these arguments about ATM efficiency sound a bit
like saying FDDI is terrible because 4B/5B encoding is only 80% efficient.

I think a more interesting measure of the value of ATM versus other
wide-area technologies is some sort of measure of throughput per dollar.