The Design And Implementation Of WAN Storage Service Discovery System

With the development of Internet and storage industry, the expanding of NGI (Next Generation Internet) based network storage makes storage service providers and users face the problem of locating storage services. Although traditional search engines and index tools are adapted to the web applications, other storage applications based on IP network are inaccessible unless the clients know the IP address or host name of the storage server.U-Stor WAN (Wide Area Network) storage service discovery system provides location service for WAN storage system, clients needn't to know the address of storage servers, the system can resolve addresses for client only with the values or descriptions of service attributes. This system consists of LAN (Local Area Network) part, middleware part and WAN part, in which the LAN part implements SLP (Service Location Protocol) and the WAN part implements Chord protocol. The system provides the clients with quick and correct location information of storage services through the communication among the three parts.The system is a 2-level network which is made up of P2P (peer-to-peer) network on WAN and local network on LAN (Local Area Network).The WAN part is based on Chord protocol with load balancing, decentralized network architecture, good scalability, good availability and easy manageability advantages. Combined with SLP, Chord can realize the wide area network service discovery functions with scalability, load balancing, easy management and other native strengths of Chord.According to the tests of 3 most common operations (registering, querying, node joining) in networks of different scale, we can draw a conclusion that the system has good scalability, and the Chord protocol significantly slowed the increase of the response time due to network node increase, speeded up the response of operation and improved the efficiency of the system.