Method and apparatus for allocating a transmission rate to source end

Abstract

An apparatus controls the transmission rates of a plurality of end stations in a computer network, and the network has at least one intermediate node. The intermediate node has a plurality of virtual circuits passing therethrough, where the virtual circuits are established between the end stations. The end stations transmit data packets at a plurality of discrete transmission rates. The end stations transmit data packets containing a field having transmission rate information. The intermediate node reads the transmission rate information for the virtual circuits, by the intermediate node detecting the transmission rate information in the field of a data packet which it receives. The intermediate node counts the number of virtual circuits using each of the discrete transmission rates. The intermediate node maintains an indication that a selected virtual circuit has been counted, and for not counting the virtual circuit more than once during a switch time interval. The intermediate node calculates a rate allocation value for the plurality of virtual circuits, and writes the rate allocation value into the field of the data packet in order to signal to the end station, and any intervening intermediate node, the calculated rate allocation value. A bit is stored in the intermediate node for each virtual circuit, each bit is initialized to a first value at the beginning of a switch time interval, and the bit is assigned a second value when a data packet having transmission rate information is detected in the selected virtual circuit by the intermediate node.