IP-SENATE: IP multicast SErvice for Non-broadcast Access networking TEchnology

In this paper we present an eecient implementation of IP multicast over ATM, called ip-senate: IP multicast SErvice for Non-broadcast Access networking TEchnology built on top of congress (CONnection oriented Group-address RESolution Service). Congress is an eecient native ATM protocol for resolution and management of multicast group addresses in a large ATM cloud. It complements the native ATM multicast mechanisms. Congress resolves multicast group addresses and maintains their membership for applications. It is not designed to handle the applications' data-exchange. Applications may use the resolved addresses returned by congress, in order to implement a many-to-many communication model (multicast group). Ip-senate is a proposal for an alternative implementation of IP multicast over ATM WAN using congress as an infrastructure. Ip-senate pursues the \cut-through" routing paradigm in order to exploit the underlying ATM QoS and native routing mechanisms in an optimal way. Ip-senate organizes IP multicast routers into logical groups, where each group corresponds to some class D IP address and contains routers that have members of this IP multicast group or senders to it in their domain. The resolution and management of these multicast router groups is performed through congress. An ip-senate extension at a multicast router uses the group membership information that it receives from congress, in order to open ATM connections that bypass (\cut-through") the IP routing mechanism. These connections either directly fan out to other multicast routers, or go through some intermediate multicast routers acting as multicast servers, in order to overcome the hardware limitation on a number of simultaneously open VCs. Ip-senate is an inter-router protocol. It provides an extension to IP multicast routers' software. Intra-domain communication may be based on either Multicast Address Resolution Service (MARS) or congress. In non-ATM networks that are connected to an ATM backbone, Ip-senate may be used in conjunction with traditional Internet Group Management Protocol (IGMP). In this work we deal primarily with the implementation of the IP multicast cut-through routing on top of congress. An outline of congress' design, however, will also be provided due to the non-triviality of group address resolution and maintenance problems that it addresses.