Mobile Ad Hoc Services: Semantic Service Discovery in Mobile Ad Hoc Networks

Mobile ad hoc networks (MANETs) are a class of networks where autonomous mobile devices with wireless communication capabilities cooperate to provide spontaneous, multi-hop connectivity. The opportunistic and dynamic characteristics of these networks make discovery of services difficult as they preclude the use of agreed, predefined service interfaces. Using semantic services and permitting their description with multiple domain ontologies is more realistic in this environment because it increases service expressiveness and does not require consensus on a common representation. However, the techniques used in resource-rich, globally connected environments to relate different ontologies and discover semantic services are inappropriate in MANETs. We present here a model for semantic service discovery that facilitates distributed ontology matching and provides scalable discovery of service provider nodes. It uses a gossip protocol to randomly disseminate ontology concepts and a random walk mechanism to identify candidate providers. The model requires no central coordination and the use of randomisation gives it good scalability properties.