Patent ID: 6680951
Filing Date: 2004-01-20
Classification: H04L

Abstract:
A system for selecting one port among a plurality of n ports having various transmission rates attached to an output adapter of a switching node in a data transmission network, and enabling a selected port to transmit data over said data transmission network, said system comprising:a data store containing a port list of identification codes for said plurality of n ports, wherein said port list is arranged in a priority order from a port having a highest transmission rate to a port having a lowest transmission rate; port service request logic providing for each one of said ports a service request signal at a frequency corresponding to a transmission rate of each of said ports, said port service request logic having for each port: a counter incremented by a base clock in accordance with a base clock period; and a wrap-value register containing a wrap value that is equal to a number of clock periods that occur during one period corresponding to the data transmission rate associated with said port for providing said service request signal when said counter reaches said wrap value; and port selection logic which selects said port in accordance with said identification code and said service request signal such that a requesting port having said highest priority is selected and enabled to transmit data over said data transmission network.