Node State Multicasting in Wireless Ad Hoc Networks

Multicasting is an essential service in wireless ad hoc networks. Applying multicasting concepts developed for wireline networks is inappropriate since they create stateful solutions (i.e. nodes learn to react to the receipt of a multicast packet.) which are short lived when topology varies. They require frequent exchanges among nodes with an attendant overhead that increases dramatically with the size of the network, its volatility, and the number of multicast groups. Nevertheless, most proposals for multicasting in ad hoc networks follow the same approach. Our proposal creates a stateless solution that uses the network state information that is already disseminated as part of the Node State Routing* (NSR) protocol. Node State Multicasting (NSM) uses this information and various packet formats to enable a rich set of multicasting capabilities. Multicast routing is implemented by explicitly listing end destinations or regions in packet headers. Intermediate nodes assume responsibility for the delivery of packets to the end destinations or regions listed in the header. Routing decisions are based on the NSR routing tables. This approach is very generic and can support both traditional wireline multicast scenarios and additional scenarios typical of wireless applications.