A dynamic programmable shared virtual path assignment algorithm for multipoint communication in ATM networks

Multicast defined as the delivery of a packet simultaneously to more than one destination by a single transmit operation is the means to achieve point-to-multipoint and multipoint-to-multipoint communication arising from the multimedia communication applications. Multipoint-to-multipoint communication requires the creation of a multicast tree. Though ATM networks are capable of providing guaranteed QoS, the support for efficient group communication (multicasting) is necessary. Unfortunately as the ATM networks belong to the class of non-broadcast multiple access (NBMA) achieving such a simultaneous transmission in terms of multicasting is very difficult. This paper addresses the issue of multicast connection establishment and proposes a new, 'dynamic programmable shared virtual path assignment' algorithm for the creation of a multicast tree. The proposed algorithm realizes each branch of a multicast tree by a segmented VP and reserves the required resources for each VP. Further, the nodes in which the multicast tree edges branch out are realized as virtual path junctions (VPJs). At VPJs two streams (VPs) of a group from two input links are merged into one input stream (VP) for an output link by performing copy or split and merge operations. The output of the merge operation at each VPJ is a function of the programmable filter installed at each VPJ. The filter may be programmed to guarantee the desired QoS of each member of a group.