Harmonic DiffServ: provisioning scalable heterogeneous-QoS multicast in DiffServ networks

A scalable quality-of-service (QoS) mechanism, termed harmonic DiffServ, is presented in this paper for supporting many-to-many heterogeneous-QoS multicasts in the DiffServ networks. In principle, it restricts data to be distributed using a limited number of multicast addresses (channels). In order to differentiate traffic with different QoS within a multicast channel, a small number of undefined DS codepoints (DSCP) are reserved for marking packets, and dynamic associations between DSCPs and service types are maintained in output ports of routers. We show that with proper arrangement on the usage of small numbers of multicast addresses and DSCPs, the forwarding information can be effectively shared among senders, which in turn significantly improves the system scalability.