Fernando Ariel Gont wrote in a message to Mike Bilow:
 MB> Once the collision has occurred, the frame sent by both will be
 MB> garbled, and each will have to be resent separately
 FAG> Ok.... another question :) : "Who" decides which card will
 FAG> re-transmit its data first? (I think it will be the card
 FAG> that was first using the line, but....)
No, each card computes a random delay.
 FAG> (I think that because if it were not like that, the card
 FAG> that was receiving the data would have to "be informed" that
 FAG> now the card that is sending information is not the same
 FAG> that the one that has been doing it...) 
The random delay also increases after repeated attempts result in collision.
 FAG> And just to finish this message :) :
 FAG> How does a card know where does the information come from
 FAG> (from which card)?
Each Ethernet card has a 48-bit number burned into it as a hardware address.  
Every such address is guaranteed to be unique in the world.
 FAG> And how can a card send information to one card and not to
 FAG> the others? 
Again, by using the 48-bit hardware address.  Broadcasts can be sent for such 
purposes as address discovery by sending to the special reserved address, 
which is 48 bits all set to 1.
 
-- Mike
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