A Network Scheduler for an Adaptive VoD Server

Most of the Video on Demand (VoD) systems were designed to work in dedicated networks. However, there are some approaches that provide VoD service in nondedicated and best effort networks, but they adapt the media’s quality according to the available network bandwidth. Our research activities focus on VoD systems with high quality service on nondedicated networks. Currently, we have designed and developed, to integrate in the VoD server, a network manager that provides: total network control, network state information, and adaptation of the transmission rate in a TCP-Friendly way. The present work describes this network manager, named Network Traffic Scheduler (NTS), which incorporates a congestion control algorithm named ”Enhanced Rate Adaptation Protocol” (ERAP). ERAP is an optimization of the well-known protocol denominated ”Rate Adaptation Protocol” (RAP). Maintaining the basic behavior of RAP, ERAP increases the efficiency of the NTS by reducing the resources usage (of the server and the network). These components has been extensively evaluated by simulations and real tests in which the resource consumption and the performance were measured. This paper presents the advantages of using ERAP instead of RAP in a VoD server, and its viability to be integrated within the NTS in a VoD server on nondedicated networks.