Mobile awared Resource Discovery with ad-hoc network

Scalability & Latency

1.Traditionally, physical entities such as a computer, network or storage system are considered as resource. With service oriented architecture, in addition to traditional physical resource, virtual services provide the consistent functionalities across the network.
2.Service Discovery: It is important for service consumer to identify service and characteristics of the service in order to understand the interfaces and authorized identity for services accessing.
3.Traditionally, service discovery is accomplished by service registry.
4.User tends to discover a service based on the knowledge of the service
5.Auto service discovery, search, selection, matching, composition and interoperation, invocation and execution requires a service description which is crucial
6.Functional classification or categories of the service is important for efficient way of querying and indexing a specific service
7.Discover, locating the network accessible capabilities, to support heterogeneous environment, standard RDS protocol and standard mechanism for expressing resource is required
8.Client normally query resource by properties such as capabilities, quality, terms, and configuration etc. Therefore the description language is demanded for resource discovery
9.Discovery is lightweight and non-authorized operation with no resource commitment. In addition, the aggregation of resource information for the purpose of large and distributed resource set needs to handle the overheads
10.Due to the boundary of the network, both physical resources and virtual services may not be reachable. The discovery model based on the network structure will not be effective. Specially for mobile aware provider and consumer applications and services, service transmission should continue with mobility. (1) Multi-cast Model (2)Directory Server Model (3) Hierarchical Directory Server Model which Directory Server located at each virtual logical boundary. The information aggregated all services in the Top level logical container. Requester unicasts the discovery queries to the server and queries will be forwarded the hierarchy. However, hierarchical model requires the deployment of the directory servers running in the upper and lower layer structure domains. The directory server in turns has to be configured in such hierarchical manner. But one thing for sure, applications in each local network does not require global network connection.
11.Flooding based unstructured P2P discovery model does not scale in terms of message overhead. Some proposed the optimized model to reduce the network traffic but increase the cost of query latency. DHT based system shows scalability and efficiency but can not handle complex query. Avoid overhead of resource discovery queries over the network, semantics-based P2P query forwarding strategy is valuable. Only forwarding query to semantically related nodes. RFD is used for resource and query expression. After the related node is identified, the original RDF query is applied to retrieve the designated information.