Method and apparatus for exchanging different classes of data during

Abstract

A digital communication network carries high and low priority data. The network stations that produce high priority data are assigned to a first group of stations and stations that produce low priority data are assigned to a second group with the two group not being mutually exclusive. Activity on the network is divided into periodic intervals of the same duration. Network control information, that defines how access to the medium, is determined is broadcast to all stations during a first segment of a periodic interval. The network control information defines the length of the periodic interval and of the periodic interval segments, and defines how many stations are in each group. Then during a second segment of the periodic interval, every station in the first group is afforded an opportunity, in a predefined order, to transmit high priority data over the medium. Stations in the second group are afforded an opportunity to transmit low priority data, when time remains after the first segment in a periodic interval before the network control information will be transmitted again. The specific station in the second group which is afforded an opportuinity to transmit first changes from periodic interval to periodic interval.