What is a late collision?
A late collision occurs when two devices transmit at the same time, but due to cabling errors (most commonly, excessive network segment length or repeaters between devices) neither detects a collision. The reason this happens is because the time to propagate the signal from one end of the network to another is longer than the time to put the entire packet on the network, so the two devices that cause the late collision never see that the other’s sending until after it puts the entire packet on the network. Late collisions are detected by the transmitter after the first “slot time” of 64 byte times. They are only detected during transmissions of packets longer than 64 bytes. It’s detection is exactly the same as for a normal collision; it just happens “too late.
