A key parameter for half-duplex Ethernet network operation. Defined as 512 bit times for Ethernet networks operating below 1 Gbit/s, and 4096 bit times for Gigabit Ethernet. In order for each transmitter to reliably detect collisions, the minimum transmission time for a complete frame must be at least one slot time, whereas the round-trip propagation delay (including both logic delays in all electronic components and the propagation delay in all segments) must be less than a slot time.