Conducting a multiparty multimedia session over ATM: using hierarchically encoded data

Heterogeneous multicast (HMC) is a communication paradigm for distributing real-time streams among multiple session participants that have different constraints and reception preferences. In HMC, sources offer streams to the participants, and each participant specifies individualized fidelity level for each stream he/she wants to receive. Participants can change their specification in mid-session. The approach is based on sources encoding streams in layers which can be individually ordered. The network provides transport that allows ordering and selective distribution of individual layers. ATM infrastructure is used for connection-based transport and cell switching. However, ATM signalling is enhanced to enable the establishment and management of multipoint, multi-VC connections for carrying multiple layers. The ATM-based network module also supports admission control, and QOS-based multipoint routes