Demand priority

Demand priority is a media-access method used in 100BaseVG, a 100 megabit per second (Mbit/s) Ethernet implementation proposed by Hewlett-Packard (HP) and AT&T Microelectronics. Demand priority shifts network access control from the workstation to a hub. This access method works with a star topology. In this method, a node that wishes to transmit indicates this wish to the hub and also requests high- or regular-priority service for its transmission. After it obtains permission, the node begins transmitting to the hub.