Transmitting multicast data packets
A method of transmitting data packets includes using one or more receive processors to receive a plurality of data packets from a network and processing the plurality of data packets using a management processor. The method also includes using one or more transmit processors to transmit packets to the network.
1. A method comprising:
receiving a plurality of multicast packets;
storing the plurality of multicast packets and packet descriptors corresponding to each of the multicast packets in a memory, wherein the packet descriptors are stored in a multicast group queue portion of the memory and include a multicast group identifier, a source identifier, and a transmit count identifying a number of times the multicast packet must be transmitted so that each of a plurality of destinations associated with the multicast group identifier receives the multicast packet;
polling the multicast group queue portion of the memory to determine whether there are any available packet descriptors;
determining the plurality of destinations associated with an available packet descriptor by comparing the source identifier of the available packet descriptor to a destination index;
transmitting each of the multicast packets to the determined plurality of destinations;
decrementing the transmit count in the available packet descriptor each time a corresponding multicast packet is transmitted; and
allowing a portion of the memory associated with the available packet descriptor and a corresponding multicast packet to be overwritten when the transmit count in the available packet descriptor reaches a predetermined value.
2. A method as in claim 1 , further comprising:
excluding the source as a destination for each of the transmitted multicast packets.
3. A method as in claim 1 , wherein the received multicast packets are stored in a packet buffer portion of the memory.
4. A method as in claim 1 , further comprising:
enqueueing packet descriptors in a transmit queue portion of the memory when the source identifier and the destination index do not match.
5. A method as in claim 1 , further comprising:
prepending headers from a connection header table for each multicast packet to be transmitted.
6. A method as in claim 5 , further comprising:
sending updates to a forwarding table, a multicast group list and the connection header table.
7. A method as in claim 6 , wherein the multicast group list comprises a plurality of entries including multicast groups stored in the memory.
8. A method as in claim 6 , wherein the multicast group list comprises a plurality of entries, each entry identifying a destination connection index and a connection type.
9. An apparatus for transmitting data packets, comprising;
a processor that executes instructions; and
a memory that stores executable instructions for causing the processor to:
receive a plurality of multicast packets;
store the plurality of multicast packets and packet descriptors corresponding to each of the multicast packets in a memory, wherein the packet descriptors are stored in a multicast group queue portion of the memory and include a multicast group identifier, a source identifier, and a transmit count identifying a number of times the multicast packet must be transmitted so that each of a plurality of destinations associated with the multicast group identifier receives the multicast packet;
poll the multicast group queue portion of the memory to determine whether there are any available packet descriptors;
determine the plurality of destinations associated with an available packet descriptor by comparing the source identifier of the available packet descriptor to a destination index;
transmit each of the multicast packets to the determined plurality of destinations;
decrement the transmit count in the available packet descriptor each time a corresponding multicast packet is transmitted; and
allow a portion of the memory associated with the available packet descriptor and a corresponding multicast packet to be overwritten when the transmit count in the available packet descriptor reaches a predetermined value.
10. An apparatus as in claim 9 , wherein the memory further stores instructions to cause the processor to:
exclude the source as a destination for the transmitted multicast packets.
11. An apparatus as in claim 9 , wherein the received multicast packets are stored in a packet buffer portion of the memory.
12. An apparatus as in claim 9 , wherein the memory further stores instructions to cause the processor to:
enqueue packet descriptors in a transmit queue portion of the memory when the source identifier and the destination index do not match.
13. An apparatus as in claim 9 , wherein the memory further stores instructions to cause the processor to:
prepend headers from a connection header table for each multicast packet to be transmitted.
14. An apparatus as in claim 13 , wherein the memory further stores instructions to cause the processor to:
send updates to a forwarding table, a multicast group list and the connection header table.
15. An apparatus as in claim 14 , wherein the multicast group list comprises a plurality of entries including multicast groups stored in the memory.
16. An apparatus as in claim 14 , wherein the multicast group list comprises a plurality of entries, each entry identifying a destination connection index and a connection type.
17. An article comprising a machine-readable medium which stores executable instructions to transmit data packets, the instructions causing a machine to:
receive a plurality of multicast packets;
store the plurality of multicast packets and packet descriptors corresponding to each of the multicast packets in a memory, wherein the packet descriptors are stored in a multicast group queue portion of the memory and include a multicast group identifier, a source identifier, and a transmit count identifying a number of times the multicast packet must be transmitted so that each of a plurality of destinations associated with the multicast group identifier receives the multicast packet;
poll the multicast group queue portion of the memory to determine whether there are any available packet descriptors;
determine the plurality of destinations associated with an available packet descriptor by comparing the source identifier of the available packet descriptor to a destination index;
transmit each of the multicast packets to the determined plurality of destinations;
decrement the transmit count in the available packet descriptor each time a corresponding multicast packet is transmitted; and
allow a portion of the memory associated with the available packet descriptor and a corresponding multicast packet to be overwritten when the transmit count in the available packet descriptor reaches a predetermined value.
18. An article as in claim 17 , further comprising instructions causing a machine to:
exclude the source as a destination for each of the transmitted multicast packets.
19. An article as in claim 17 , wherein the received multicast packets are stored in a packet buffer portion of the memory.
20. An article as in claim 17 , further comprising instructions causing a machine to:
enqueue packet descriptors in a transmit queue portion of the memory when the source identifier and the destination index do not match.
21. An article as in claim 17 , further comprising instructions causing a machine to:
prepend headers from a connection header table for each multicast packet to be transmitted.
22. An article as in claim 21 , further comprising instructions causing a machine to:
send updates to a forwarding table, a multicast group list and the connection header table.
23. An article as in claim 22 , wherein the multicast group list comprises a plurality of entries including multicast groups stored in the memory.
24. An apparatus as in claim 22 , wherein the multicast group list comprises a plurality of entries, each entry identifying a destination connection index and a connection type.