Patent ID: 7881244

Claim:
A memory of a router, the memory comprising: a data structure stored in the memory, the data structure including information relating to a set of multicast sessions being handled by the router and including: a plurality of pairs of a source field and a group field ({S, G} pairs) stored in the memory, in which each pair of the plurality of {S, G} pairs defines a multicast session of the set of multicast sessions and wherein the source field defines a source of a multicast transmission and the group field defines a group corresponding to the multicast session; a first pointer associated with each of the plurality of {S, G} pairs that points to a dynamically allocated set of OIF blocks, wherein a number of outbound interface (OIF) blocks in the set of OIF blocks is dependent upon how many of a plurality of OIFs of the router are currently participating in the multicast session and the number of OIF blocks in the set of OIF blocks defines how many times packets associated with the multicast session are to be replicated; a set of slots associated with each OIF block of the set of OIF blocks, each slot of the set of slots configured to store a second pointer to a transmit control block (TCB) which services one or more users participating in the multicast session and which represents a data structure configured to store control information relevant to processing or routing packets, including information regarding an OIF of the plurality of OIFs out which the packets are to be transmitted; a third pointer associated with each OIF block of the set of OIF blocks to chain together the set of OIF blocks and thereby allow dynamic addition or removal of OIF blocks to or from the set of OIF blocks responsive to users joining or leaving the multicast session.