Method for multicast service in a crossbar switch

A system for multicasting a data cell received in a crossbar switch structure, comprising:

• a multicast controller for performing a multicast control function for an ingress port of the crossbar switch, the ingress port being one of a plurality of ingress ports of the crossbar switch;
• and
• a multicast grant generator coupled to the multicast controller for granting multicast service to a data cell the ingress port;
• wherein the system performs a process for multicasting a data cell received in the crossbar switch structure, the process comprising:
• registering an address and priority corresponding to the data cell at the ingress port in a memory cell, the memory cell being addressable by the priority of the data cell, the ingress port being one of a plurality of ingress ports for the crossbar switch;
• controlling a flow of the data cell, the flow being based on the priority of the data cell;
• asserting a multicast service request for the data cell using the memory cell;
• in response to the asserting of the multicast service request, comparing a request priority for the data cell with request priorities of one or more other multicast data cells asserted for ingress ports of the crossbar switch;
• responsive to the comparing of request priorities selecting the data cell for transmission and granting the multicast service request for the ingress port by the multicast grant generator;
• arranging a multicast fan-out for the data cell to a plurality of egress ports of the crossbar switch;
• and
• in response to the arranging of the multicast fanout for the data cell, configuring the crossbar switch structure for the transfer of the data cell to the plurality of egress ports of the crossbar switch.

A method for multicasting a multicast cell in a crossbar switch, comprising:

• recording an address ‘i’ and a priority ‘p’ of the multicast cell in a multicast storage register set at a port ‘n’ of the crossbar switch, the storage register being addressable by the priority of the multicast cell;
• re-shuffling a service order in the storage register set based upon the priority ‘p’ of the multicast cell;
• controlling a flow of the multicast cell in the multicast storage register set based on the priority of the multicast cell;
• asserting a multicast service request through the storage register;
• in response to the asserting of the multicast service request, comparing a request priority for the multicast cell with request priorities of one or more other multicast data cells asserted for ingress ports of the crossbar switch;
• responsive to the comparing of request priorities, selecting the data cell for transmission and giving a multicast service grant for the multicast cell;
• in response to giving the multicast service grant, generating a plurality of request signals corresponding to the fan-out of the multicast cell to a plurality of egress ports of the crossbar switch;
• in response to generating the plurality of request signals, making a transfer request to a plurality of egress ports corresponding to the fan-out;
• in response to said making, giving a plurality of grant signals from the plurality of egress ports to the port ‘n’;
• correspondingly configuring the crossbar switch to transfer the multicast cell;
• and
• in response to configuring the crossbar switch, transferring a payload of the multicast cell to the plurality of egress ports.