An overlay framework for provisioning differentiated services in Source Specific Multicast

Scalability in QoS-aware multicast deployment has become an important research dimension in recent years. In this paper we propose a new scheme named Differentiated QoS Multicast (DQM) based on the Source Specific Multicast (SSM) model in order to provision limited qualitative QoS channels for supporting heterogeneous end users. In a similar fashion to the Differentiated Services paradigm, in DQM the network is configured to provide unified QoS classes to both content provider and receivers. Based on Service Level Agreements, both sources and group members should select a specific QoS channel available from the network for group data transmission, and hence arbitrarily quantitative QoS states are eliminated. Moreover, we use the group address G contained in the (S,G) tuple in the SSM service model to encode QoS channels, and data packets belonging to the same QoS channel identified by a common class D address can be treated aggregately within core networks. Hence the proposed DQM scheme can be regarded as an overlay solution to the DiffServ paradigm, specifically for single source multicast applications.