Multicast Server Method Using Multiple VCs for IP Multicast over ATM

In the Internet, multimedia services, such as video streaming, TV conference, should be supported by multicast communications, i.e. IP multicast, in order to reduce total bandwidth necessary for distributing streaming programs. Below data-link layer, IP can use any network technology and ATM is the most promising one for a backbone network. IP multicast is based on the connection-less communication and ATM on the connection-oriented communication. In order to integrate these two opposite-side network architectures, IP multicast over ATM is proposed in IETF. For implementing this technology, two VC configuration methods are proposed; the mesh method and the server method. In this paper, we propose a multi-VC server method which is based on the server method. In the server method, Head-Of-the-Line-like blocking of ATM Adaptation Layer Service Data Unit (AAL SDU) at the multicast server degrades throughput performance. It is because the multicast server is admitted to set up only one VC per multicast group for data transmission and ATM cells fragmented from the same AAL SDU should be transmitted in serial without mixing other cells. The multi-VC server method solves this problem by setting up multiple VCs from the server. Multiple VCs enable the server to transmit data cells from different senders in parallel. By simulation results, we discuss the merit of this method.