Compound VC mechanism for native multicast in ATM networks

The growth of new kinds of traffic, and particularly multimedia, leads to changes in the conception of the network. Multimedia group communications pose stringent requirements to the distributed system supporting them. Maybe the most important requirement is that they should allow the communication from a user in a group to the rest of the group in an efficient way. These communications are referred to as multicast communications. The most efficient way to offer them in terms of resource consumption is at the level where either routing or switching are carried out. ATM poses further challenges due to its connection-oriented nature. Some mechanisms have been proposed in the past either for integrating IP multicast with ATM or for providing native ATM multicast but they present some drawbacks, especially in terms of overhead, management, and scalability. This paper presents a new native ATM multicast proposal that solves some of the problems found in other mechanisms. The multicast group is associated to a group of adjacent VCs (compound VC). A unique entry in the switching table is needed to switch the traffic of the entire group by means of a mask. The variable part of the VCI is dynamically changed each time the first cell of a new PDU arrives to a switch.