A Multi-QoS Constraints Based Multicast Extension To OSPF

In recent years, multimedia applications on Internet such as video-conferencing, real time audio, remote leaning, etc, are springing up.Most of these applications are shared by group of users and needed to be supported by multicast technology, requiring network metric such as large bandwidth, stringent delay and delay jitter and so on.While most of the multicast protocols running on today's Internet are for best-effort services which have no guarantee for these metrics.There is an urgent need to design and implement multicast protocols with quality-of-service (QoS) guarantee, also routing protocols like OSPF (Open Shortest Path First), which is one of the most widely used routing protocol, must be extended suitably.Hence, a practical multi-QoS constraints based multicast extension to OSPF is raised here.The purpose of the scheme is to give out an multicast extension to OSPF that can build multicast tree incrementally and thus supports fully dynamic memberships and heterogeneous receivers with the satisfaction to the stringent QoS constraints on the path.The method is minimize the cost of the tree by letting a node to join the tree via a low-cost path and may later switch to a higher-cost but more QoS stringent path when necessary.The result is that the delay-Jitter-SPF algorithm and the flow graph of the building of the multicast tree with QoS constraints are proposed.With the discussion on computation complexity and control overhead, the algorithm can efficiently utilize resources and provide a QoS stringent path for a mlticast member in a network which is runnig on OSPF.