Research On Resource Locating Scheme In Peer-to-Peer Platform

The existent resource locating systems only support simplex pattern. The locating network has poor performance on scalability, and it is difficult to maintain. It doesn't have the guarantee of accurate locating delay; moreover, the network overhead caused by message flooding is large. As a result, the existent resource locating systems are not suitable for the large scale and complex network applications.Aiming at the problems mentioned above, the resource locating system based on peer-to-peer network platform combines the characteristics of both unstructured and structure resource locating schemes. It supports precision locating model and the fuzzy locating model as well. And it can be easily resilient and maintained with high reliability, low cost, and short locating delay. The system employs the multi-layered architecture to separate node as super nodes and ordinary nodes. The former can act as the transaction agency for the latter in order to reduce the scale of main locating network. The system constructs DHT route table according to the Meridian service ring during the building process, so as to support precision and fuzzy locating models. Network information is exchanged among nodes by the Gossip protocol and DHT route table index which adjusts the network topologic parameters in time and optimizes the locating network dynamically. The resources index raises the speed of locating by means of the uniform specification description and Tag-based memory. When publishing the resource index, it adopts the index upload conversation technology to supervise the index uploading process and reduce the message redundancy effectively. The locating request carries control and transmitting path information to make the message transmitting directionally without flooding. After locating, successful locating message will be transmitted conversely according to the transmit path which carried by the locating request so that the node updates the buffer table according to the locating buffer strategy and makes full use of the history information by which raising the locating efficiency.The resource locating simulation system is implemented based on Windows operating system and Visual.NET development environment. The system performance is evaluated by analysis of the experiment data. The analysis indicates that when there is no increase of the average delay time, the nodes in route table distributed evenly. The success rate of the locating system is greater than 80% which is 10% higher compared with the KAD system. The average locating hops is between 3 and 7, the average locating delay time is between 15ms and 25ms. In the network of different scales, the average locating hops and the delay time fluctuates narrowly. The average locating delay is reduced 20% comparing to the KAD system. With the increasing of neighbor node number, the performance of the system gets enhanced, while the changing scope is not wide. In conclusion, the system improves the performance of resource locating efficiently.