Order persistent timer for controlling events at multiple processing stations

摘要

An order persistent timer is provided in each station on a network to control the timing of transmission of each isochronous data packet from a station, and to also control the timing of transmission of asynchronous data packets that include reservation requests. The OP timer at each station monitors traffic on the network from other stations to detect whether the network is active or idle. In an active state, the OP timer times a set interval of time sufficient to indicate the successful transmission of a packet on the frame. In the idle state (no packet on the network from another station), the OP timer times a number of deferral time intervals that are used with a network interrupt handler at the station to control the transmission of isochronous data packets without collision, and asynchronous data packets thereafter.