NFE setting manually to 1000baseT and half duplex

Jon Radel jon at
Sun Jun 8 16:01:33 UTC 2008

Wojciech Puchar wrote:
>> Even if you do have hardware that supports half-duplex gigabit ethernet
>> on both ends, the need to do carrier extension for any frame shorter
>> than 512 bytes so that CSMA/CD actually works on a reasonable sized
>> cable, does horrible things to your throughput if you've got lots of
>> small frames. (In other words, at gigabit speeds, frames smaller than
>> 512 bytes zip down the wire so quickly that you can no longer reliably
>> detect collisions, so the frames all get padded.) I'm having trouble 
>> wrapping my head around any circumstances other than horribly, 
>> horribly broken hardware or software where half-duplex would increase 
>> your performance over full-duplex.
> actually there are no gigabit devices incapable of full-duplex.

I would certainly hope so; I can't see much of a market for gigabit 
ethernet devices that can't do full-duplex.  (I'm a touch confused, 
however, by your phrasing that as if you're rebutting something I wrote.)

--Jon Radel
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