Patent ID: 6272147
Filing Date: 2001-08-07
Classification: H04L

Abstract:
A method of operating a data network having a bus and a plurality of stations operable to transmit data on the bus, comprising the steps of:assigning respective rankings to those stations which wish to transmit on the bus;performing by those stations which wish to transmit on the bus, a contention resolution process whereby those stations transmit in cycles;transmitting, by those stations which wish to transmit on the bus, within each cycle in an order determined from their ranking,wherein the step of performing the contention resolution process comprises the steps of:transmitting a jam on the bus for up to a period of time dependent on the current ranking of that station; anddetecting whether there is a collision on the bus while transmitting the jam; andif not, enabling transmission of data,the method further comprising the step of making each station operable to perform a fairness process, which comprises the steps of:detecting whether one of the stations has transmitted data succeeding a jamwithout a collision; andif not, disabling its contention resolution process until such a detection has been made,the method further comprising the step of:refraining by each station which wishes to transmit further data immediately after it has transmitted data in a current cycle, from the contention resolution process until it has determined that the current cycle has been completed.