[rescue] RE: Time division and collision domains!

Paul Sladen rescue at sunhelp.org
Wed Jun 27 09:38:28 CDT 2001

On Tue, 26 Jun 2001, James Fogg wrote:

> On Tue, 26 Jun 2001, THOU SPAKE:
> >> You can not get 10 Mb/s through a 10 Mb/s ethernet port - period. 
> Yeah, you almost can. TCP's send/ack is a limiting factor, and the required
> wait-times between packets is another factor. Up the MTU to a higher number,
> switch to a UDP protocol and stream packets and you can very close to 10Mbs.

Ethernet MTU is 1500 (1506) which is the standard anyway, everywhere.

> >> When an Ethernet device has a packet to send, it does,
> Ummm... no it doesn't. Find a website that describes CSMA.

First Listen;  Send;  Listen while sending;  If you read crap, then carry on
sending crap so that everyone notices you're sending crap,  wait a *random*
time and send it again;  If you read what you sent then everything is OK.
Same story -- go over 75% ultilization, and preformance starts going down.

> >> I suspect USB uses some sort of sync signal, and
> devices consume time slices. >  

I once went to a talk by Mitsushitty who were trying to sell me USB chips;
wished I'd listened more and spent less time corning them about when they
were going to wake up and ship their Development Environment ported to Linux.


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