IP multicast services over ATM multicast

摘要

A method and apparatus for reducing bandwidth usage in an ATM switching network by controlling bandwidth used for IP multicasting through the switching network. Bandwidth usage is controlled by modifying ingress and access modules, such as IP service gateways and access modules that terminate branches of a multicast tree. If a join request is received at an IP service gateway from a sink node served by an access module, the IP service gateway instructs the access module to graft a leaf to the branch to join the sink node to the tree and to merge the multicast packets with other IP packets for the sink node. Consequently, only one connection carrying the multicast traffic is required between the IP service gateway and the access module. Bandwidth usage in the ATM switching network is thereby controlled, and bandwidth usage in service access trunks connecting the access modules to the ATM switching network is reduced.