Flow control in a cell switched communication system

摘要

In a cell switched communication system in which a source is connected to a network for transmission of cells to a network destination via a network element (1) having a plurality of ports (3,4), said source generating resource cells containing information concerning a bandwidth allocated to the source for transmitting cells, a method of providing flow control at the network element (1) comprises the steps of: (a) detecting a resource cell as it is received at an input port (3) of the network element; (b) routing the resource cell to a resource cell processing means (2) common to all the ports of the network element; (c) modifying information contained in the resource cell concerning the bandwidth allocation for the source on the basis of a determination of current utilisation of ports of the network element; and, (d) passing the modified resource cell to an output port (4) of the network element for subsequent return to the source. Resource management (RM) cells received at an input port (3) of a network element (1) in an ATM communication system are routed to a centralised resource cell processing means (2) where information in the resource cell relating to the bandwidth allocation of the source is modified to take account of the available bandwidth. The RM cell is subsequently passed back to the source to enable the source to modify its transmission rate to correspond to the modified allocated bandwidth for that source and thereby ensure that cells are not discarded by the network element due to traffic congestion.