Inter-session fairness support for network-based layered multicast

Abstract

To support distribution-style video multicast in a dynamic network environment like the Internet, many adaptation methods have been proposed. Layered multicast is well-known approach as a reasonable method to support this; video data are encoded into multiple layers - base layer and enhancement layers. Then source transmits the encoded data over separate multicast groups. On the basis of this layered multicast, in a receiver-driven approach, each receiver decides how many layers it accepts depending on its capability or desired level of quality of service. This approach has advantages with respect to performance or scalability, however, it can cause network fluctuation frequently due to the limitation in controlling with global view for dynamically changed network status. To overcome this limitation, as another approach, network driven approach is introduced. Network-based approach allows more rapid adaptation and can control network status in a timely manner, thereby achieving stability and fairness between multiple video sessions. However, network-based schemes proposed till now do not handle properly for TCP-fairness since they control for total traffic existing in a queue, no identifying individual session. Even though TCP-fairness, in video multicast, should be considered importantly to avoid the congestion collapse of the Internet, the existing solutions cannot be applied to a network-based approach since all schemes are RTT-based. Therefore, in this paper, we analyze the Network-based Layered Multicast (NLM) scheme, which is the most recently proposed network-based protocol, and then based on its result, we propose the enhanced algorithm that supports TCP-friendly and more stable video multicast in a network level and cooperates with receiver for improvement of link utilization. The proposed algorithm achieves TCP-fairness and stability using bandwidth occupation ratio and the number of video sessions in network traffic. It also achieves improved link ut...