Review: t=0 A transmit t=576 A finish transmitting In worst case, B start transmitting at t=224 t=224+225=449, B's first bit arrives at A Because 449<576, aborts before completing the transmission of the packet, as it is supposed to do. Thus cannot finish transmitting before it detects that transmitted. This implies that if does not detect the presence of a host, then no other host begins transmitting while is transmitting.