Study On Service Discovery Protocol For Mobile Ad-hoc Networks

Wireless Mobile Ad Hoc Networks (MANETs) are very special wireless networks, in which the nodes use their neighbor nodes (in direct transmission range) to forward the data packet one by one and each node acts as a router of its neighbors. These characteristics make MANETs not be bound by the communications infrastructure and can be constructed rapidly in some special circumstance such as emergency service and disaster relief,field observation etc. With the applications and development, the scale and range of MANETs is becoming larger and larger. How to manage so many services in MANETs to improve availability of MANETs become a new task. Service discovery is the operation of finding proper servers that provide services matching one's request. Service discovery technology tries to approach zero administration overhead and thus free users from tedious administrative and configuration work. For resource- constrained MANETs, nodes often need services and resources supported by others to work effectively, which require service discovery technology. Service discovery protocol is critical to the success of high dynamic MANETs.Although in recent years some protocols have been presented to support service discovery specifically targeted at MANETs environments, the research of service discovery for MANETs is also a severe challenge for its unique requirement (i.e., a shared wireless medium, multi-hop routes and their dynamic changes, limited computing and networking resources, and etc.). thus simple and efficient service discovery protocol is very important for MANETs.Although existing service discovery for MANETs differ in approach used for searching and providing desired services, they are mostly middleware oriented solutions and have the common assumption that some routing protocols may exist underneath for supporting request/service delivery from clients to service providers or visa versa. This can make them inefficient use in wireless MANETs due to redundant control packets flooding problem, possibly causing extremely high network overhead. It is important to observe that both protocol for service discovery and route discovery are based on a network-wide flooding mechanism with different goals of discovery. For the process of service discovery in MANETs is very similar to that of route discovery in on-demand routing protocols, we consider the integration of these two discovery problems using cross-layer design methodology such that service discovery can be supported along with route search for those services-CAODV, which is helpful to improve network performance.Since MANETs are very susceptible to security threats, we propose an enhanced protocol SCAODV based on CAODV, which using symmetric encryption technology to support secure authentication. Service authentication process is started when service discovery request is begin, service requesters and providers can be authenticated and services can be used credibly and securely.