Multi-pass Transmission Policy: An Effective Method of Transmitting Large Multimedia Objects in the Wide-Area Network

Multimedia objects such as audio, video and images are usually very large in si>lc and used in time-critical applications. The traditional method of transmitting these large objects over a WAN is to use TCP because of the high loss rate of IP datagrams over a WAN. In this paper, we propose a new method called Multi-pass Transmission Policy (MpTP). The basic idea of MpTP consists of three things: sending small packets, selective retransmission requested by the receiver, and multi-pass transmission. MpTP function by sending small packets and packets not received on the first pass are retransmitted on the second paBS and so on till the required reliability is reached. We conduct experiments on both MpTP and TCP to compare the efficiency of the two protocols. Experimental results indicate that when transmitting large objects, MpTP can, on average, be aB much aB 4 times faBter than TCP. In addition to the efficiency, MpTP can support mUlti-resolution, degrees of reliable transmission and ·This research is partly supported by a grant from NSF under NCR-9405931