Experience in designing a using TCP as transport protocol VOD system over a dedicated network

Abstract

In this paper we address the problem of designing a TCP[11] and IP[10] (TCP/IP for short) based video on demand (VOD for short) system over a dedicated network based on standard internet protocols, ie., Transmission Control Protocol (TCP for short, IETF RFC 793[11]) and Internet Protocol (IP for short, IETF RFC 791[10]). TCP and IP are usually refered together as TCP/IP. Despite of the general belief that TCP/IP is not suitable for real-time multimedia applications, after testing in laboratory environment for about one year we are confident in announcing that our prototype is both efficient and reliable. This success depends on several important factors. First of all, the system operates on a dedicated network in which there exists no other traffic except a light of background traffic generated by the Ether Switch the major network component used by our prototype. Second system overhead due to the VOD server and the network adaptor card is minimized Third, we maximize disk bandwidth by implementing a proprietary disk file system. Our experiment shows that it requires only about 330 KBytes at the client buffer to smooth packet delay jitters. In our experimental environment, due to resource limitations, up to 40 clients had been tested successfully. By looking at network bandwidth and CPU utilization, we estimate that a single VOD sewer should be able to handle more than 40 interactive clients playing MPEG-1 system streams simultaneously.