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Date:      Thu, 24 Feb 2000 14:07:40 -0500 (EST)
From:      Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
To:        Chris Wasser <cwasser@v-wave.com>
Cc:        freebsd-current@FreeBSD.ORG
Subject:   Re: dc0 wierdness with Compex Freedomline
Message-ID:  <200002241907.OAA27437@khavrinen.lcs.mit.edu>
In-Reply-To: <20000224102131.A1796@area51.v-wave.com>
References:  <20000224120438.A24299@shadowmere.student.utwente.nl> <20000224102131.A1796@area51.v-wave.com>

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<<On Thu, 24 Feb 2000 10:21:31 -0700, Chris Wasser <cwasser@v-wave.com> said:


> The theoretical maximum for 100BaseT-FDX (which is 200Mbps) is 25MB/s
> (megabytes per second), 100BaseT-TX is 12MB/s [FYI: Mbps->MB/s you divide
> by 8] I realize my punctuation may be off, but there you are.

Assuming you mean ``100BASE-T (half duplex)'' here... This is not
quite right.  In a CSMA/CD medium access protocol, like that used by
Ethernet, the actual capacity of the link is always(*) somewhat less than
100%; the exact value depends on the precise parameters of the
transmissions at both ends.(**)

-GAWollman

(*)In non-trivial conditions; i.e., when actual work is being done.

(**)I've heard numbers between 70% and 95%.

--
Garrett A. Wollman   | O Siem / We are all family / O Siem / We're all the same
wollman@lcs.mit.edu  | O Siem / The fires of freedom 
Opinions not those of| Dance in the burning flame
MIT, LCS, CRS, or NSA|                     - Susan Aglukark and Chad Irschick


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