A routing mechanism for guaranteeing heterogeneous QoS in the Internet

The current researches for guaranteeing heterogeneous QoS can be classified into two different mechanisms: resource reservation on the network and adaptation of layered multicast. Since RSVP (resource reservation protocol) signaling is used in the first mechanism, a quantitative QoS guarantee is possible. However, all routers along the path must maintain the states of each session in the first mechanism. That may cause a scalability problem. Therefore, this mechanism cannot be easily applied to current networks. The second mechanism divides the application flow into several layered sub-streams with layered encoding mechanisms. This sub-stream is delivered along each multicast channel. The routers in this mechanism must identify the priority for each stream packet. Also, when it comes to the issue of management of the multicast session and address allocation, the complexity increases to a practical amount. We propose a new heterogeneous QoS mechanism in order to solve the above problems. This mechanism is mostly based on the distinction between the generated streams by layered encoding. In this mechanism, the receiver, who does not have enough link bandwidth, is serviced only by the stream with basic quality. On the other hand, the best quality service is provided to the receiver who has enough link bandwidth. The decision on the quality is quickly done by each router according to the current link bandwidth of each interface.