MULTICAST SWITCHING IN A CREDIT BASED UNICAST AND MULTICAST SWITCHING ARCHITECTURE

摘要

A system and method of switching packets and/or cells, which includes a switching apparatus having a plurality of input units that receive at least one packet to be transferred by the switching apparatus. A plurality of output units transfer the packet out of the switching apparatus. A switch unit transfers the packet from one of the input units to one of the output units. Each input unit includes at least one input queue that temporarily holds the packet to be transferred by the switching apparatus. Each input unit also includes a respective unicast credit count unit that allows the packet to be transferred out from the queue when a current unicast credit value determined by the unicast credit count unit is at least predetermined value. Each output unit includes at least one output queue that receives the packet as switched by the switch unit, and which is to be transferred out of the switching apparatus. Each output unit also includes a output port scheduler unit that generates credit tokens and that outputs credit messages based on the credit tokens generated. Multicast credit count units are provided for each QoS priority that a multicast packet can be set to, in which they maintain a current multicast credit value for the QoS priorities.