A Research On Service Discovery Model For Mobile Ad Hoc Networks Based On Zrp》

Mobile Ad hoc Networks (MANET) can be randomly deployed at anytime and anywhere, without relying on any existing infrastructure. As fundamental application environment of Pervasive Computing and The Internet of Things, MANET has the characteristics of the distributed structure and the flexibility of networking, so its application is becoming more and more widely. The key problem of its application is how to efficiently discover services in time and use the services provided by the network nodes. Traditional service discovery protocols require a stable infrastructure. When these protocols are directly used to the dynamic topology and resource-constrained MANET, they have problems of low efficiency, broadcast storm, and so on.The majority of application-layer service discovery protocols, which were designed for MANET, demand a kind of support of network-layer routing protocol in process of service discovering. Hence, it is bound to bring about overlapped function broadcast packets, and result in a problem of data redundancy. In order to solve this, we propose a lightweight network service discovery model ZSDMAN (ZRP-based Service Discovery Model for MANET) based on the ZRP(Zone Routing Protocol). At first, this model integrates the service discovery with routing discovery, and introduces the zone radius determination algorithm. So it is unnecessary to pre-set node zone radius, and the value of each node zone radius can be different. Secondly, according to the characteristic of hybrid routing mechanisms of ZRP, in the intra-zone, a push-based service advertisement mechanism, which is used to advertise the service information in the zone, is adopted. In order to avoid service advertisement messages flooding into the whole network, those messages are only relayed inside zone; In the inter-zone, a pull-based service discovery mechanism, which is used to locate service information provided by the nodes outside zone, is adopted. Service query messages are transmitted by the BRP(Broadcast Resolution Protocol), which could avoid overabundant broadcast data packets that cause by traditional service discovery protocols implemented by using the flooding broadcast strategy.Finally, we simulated the model by using NS-2 network simulator and verified the validity of ZSDMAN. We evaluated its performance on both control overhead index and service query latency index. The simulated results show that this model could availably decrease the control overhead and reduce the service query latency to some extent.