David L. Martin on Tue, 27 Apr 1999 18:38:07 -0400 (EDT)

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RE: major collision, nobody hurt

This is all by memory so take this with a grain of salt:

E1 is a ethernet card installed on a network,
EX is any other ethernet card installed on the network.

E1 needs to TX a packet,
E1 waits until is doesn't see any tranfic on the line,
E1 starts a timer with a random timeout,
When E1's timer runs out it checks to see if anyone is
transmitting, if not E1 transmits this packet,
While transmitting it "listens" to its own packet being transmitted.

If it receives its own packet back then there was no collision.
If it does not see its own packet, then EX was transmitting at the same
time, thus a collision occured.

On networks with a few dozen EX's, collisions should be a very rare thing.


David L. Martin        <dlmarti@njcc.com>
R&D Software Engineer  http://pluto.njcc.com/~dlmarti
PGP: 16 C0 C0 AB 4E A2 2C 89  FF 8B 07 CF C0 72 3D 89

English is a difficult second language for most programmers. 

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