(Or contention period). Minimum time a host must transmit

for before it can be sure that no other host's packet has

collided with its transmission. If the maximum propagation

delay from one host to any other is T, then a host that starts

to transmit at time t0 may collide with a host that starts

just before t0 + T. The first host will not detect the

collision until time t0 + 2T.