Scalable IP-services enabled multicast forwarding with efficient resource utilization

摘要

Methods, apparatus and data structures are provided for managing multicast IP flows. According to one embodiment, active multicast IP sessions are identified by a router. A data structure is maintained by the router and contains therein information regarding the multicast sessions, including a first pointer for each of the multicast sessions, at least one chain of one or more blocks of second pointers and one or more transmit control blocks (TCBs). Each first pointer points to a chain of one or more blocks of second pointers. Each second pointer corresponds to an outbound interface (OIF) participating in the multicast session and identifies a number of times packets associated with the multicast session are to be replicated. The TCBs have stored therein control information to process or route packets. Each second pointer points to a TCB that identifies an OIF of the router through which packets are to be transmitted.

主权项

1. A method of managing multicast Internet Protocol (IP) sessions, the method comprising:
identifying, by a router, active multicast IP sessions; and maintaining, by the router, a data structure within a memory of the router containing therein information regarding the active multicast IP sessions; wherein the data structure includes:
a plurality of pairs of a source field and a group field ({S, G} pairs), in which each pair of the plurality of {S, G} pairs defines a multicast IP session of the active multicast IP sessions, wherein the source field defines a source of a multicast transmission of the multicast IP session and the group field defines a group corresponding to the multicast IP session;a first pointer associated with each of the plurality of {S, G} pairs that points to a dynamically allocated set of outbound interface (OIF) blocks, wherein a number OIF blocks in the dynamically allocated set of OIF blocks is dependent upon a number of OIFs of the router that are participating in the IP multicast session and the number of OIF blocks in the dynamically allocated set of OIF blocks defines a number of times packets of the IP multicast session are to be replicated;a set of slots for each OIF block of the set of dynamically allocated OIF blocks, each slot of the set of slots having stored therein a second pointer to a transmit control block (TCB) data structure which services one or more users participating in the IP multicast session and which has stored therein control information to process or route packets of the IP multicast session, including information regarding an OIF of the router through which the packets are to be transmitted;a third pointer associated with each OIF block of the set of dynamically allocated OIF blocks that links together the set of dynamically allocated OIF blocks and facilitates dynamic addition or removal of OIF blocks to or from the set of dynamically allocated OIF blocks responsive to users joining or leaving the IP multicast session.