nanog mailing list archives

Re: 10 gige experience


From: "Richard A. Steenbergen" <ras () e-gerbil net>
Date: Thu, 10 May 2001 14:20:10 -0400 (EDT)


On Thu, May 10, 2001 at 11:12:21AM -0400, Greg Maxwell wrote:

On Thu, 10 May 2001, John Fraizer wrote:

Anyone know any good articles on 10GB ethernet? I am specifically
intrested if they have removed some of the legacy requirements that
hamper gigabit ethernet (such as a default MTU of 1500, half-duplex,
etc.)

Half-duplex?  The last time I checked, my GigE equipment didn't default
to half-duplex.

No I wouldn't expect it to, nor did I state anything about defaulting
to half. There is no purpose for half-duplex in GIGE, even the few
GIGE hubs I've seen are buffered and user congestion control to allow
full duplex operation.  The possibility of half-duplex mode just adds
unneeded cruft and additional failure modes.

If it didn't support half-duplex, it wouldn't technically be 802.3
ethernet. Full duplex is what happens when you remove CSMA/CD.

I'm sure 99% of people out there have absolutily no need or desire for
half duplex gige or 10gige, and I'm also sure 99% of people out there
would be far better served by a larger MTU. Unfortunantly it's the other
1% at IEEE who write the spec.

-- 
Richard A Steenbergen <ras () e-gerbil net>       http://www.e-gerbil.net/ras
PGP Key ID: 0x138EA177  (67 29 D7 BC E8 18 3E DA  B2 46 B3 D8 14 36 FE B6)



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