Patent ID: 6771648
Filing Date: 2004-08-03
Classification: H04L,H04Q

Abstract:
A switch for a network which switches traffic of connections admitted by the switch comprising:an input port mechanism which receives traffic of connections on at least one link from the network, each connection having a priority; an output port mechanism which sends traffic of admitted connections to the network; a controller which serves connections, which computes a dynamic estimate of an effective bandwidth of the link, and which monitors the admitted connections received by the input port mechanism and sent by the output port mechanism and releases admitted connections according to a priority of an admitted connection when an overload condition exists in the switch, said controller connected to the input port mechanism and the output port mechanism, each connection requesting a specific bandwidth from the controller, the overload condition includes receiving more traffic on admitted connections received by the input port mechanism than the controller can process at a given time, the controller determines excess bandwidth associated with the overload condition, and the controller releases the admitted connection, for a given priority, with the closest match to the excess bandwidth, the controller releases admitted connections according to the admitted connections' traffic class, where UBR connections are released first, then ABR connections are released next, then VBR connections are released next and then CBR connections are released from the switch, the input port mechanism comprises I input ports connected to the controller, where I is an integer and greater than or equal to 1; and wherein the output mechanism comprises O output ports connected to the controller, where O is an integer greater than or equal to 1, the controller releases the admitted connection with the lowest priority; and a buffer mechanism connected to the output port mechanism and wherein the overload condition exists if the sum of requested bandwidths of admitted connections on an output port is greater than the output port's bandwidth and buffer resources associated with it are being exceeded, if (Qvcbr>T) and (Bleff>Blink) where Qvcbr is the buffer occupancy for VBR/CBR traffic, T is a threshold, Bleff is the aggregate effective bandwidth of connections on link l, and Blink is the maximum link capacity or line rate.