Demand priority is an access method designed for the 100 Mbps Ethernet standard called 100 VG-AnyLAN. The 100VG-Anyl_AN network comprises repeaters and end nodes. An end node could be a computer, bridge, router or switch. The function of the repeater is to search for requests from all nodes on the network. In a demand priority network, computers can receive and transmit at the same time. This is because four pairs of wires are used in the cabling scheme defined for this method. In demand priority, communication is only between the sending computer, the hub or the repeater, and the destination computer. This method is more efficient than CSMA/CD, which sends transmission to the entire network.
