Research On Intermediate Routes Detection Scheme In Peer-to-Peer Network

With the popularity of Skype system, Telephony or Voice over Internet Protocol(VoIP) application has been booming to a promising service. However, the configuration of BGP protocol and depolyment of Internet infrastructure leads to the routing inefficiency and frequent congestion even path failure of current network layer. The best-effort Internet can't readily satisfy the service guarantee of applications as VoIP often require.Traditional direct connection through the default route is no longer suitable to provide service for many applications.Peer-to-peer technology has been successfully applied into overlay routing schemes. The leverage of intermediate route node selected from overlay network which has the characteristic of diversity and heterogeneity can provide powerful forwarding capacity to resolve the problems mentioned above. According to the requirements as low time delay, low packet loss rate and high speed of update, the intermediate relay detection system should utilize different modules to execute separate tasks, such as infomation collection, nodes probing, status transaction and so on and as well takes full advantages of global topology knowledge in order to reduce the rudderlessness by filtering out useful node from millions of hosts. Among the three algorithms presented, the improved random probe scheme leans upon AS information to partition the network into several blocks where the relay nodes are randomly chosen from. By doing this it improves the relay node detection hits ratio.The delay binary tree scheme makes use of binary tree to provide a favorable quick index and insert ability in local area. And the AS-aware scheme employs a three leveled architecture: a centre AS information server to dissemiate the IP prefix-AS mapping table, several landmark servers to maintain local relay nodes set and all the supernodes to probe and detect the available relays by constructing multi-resolution rings. It sufficiently makes use of threashold information between ASes to realize the relay discovery in the process of building overlay and relies on the self-contained message exchange mechanism to achieve the goal of providing stable, high end-to-end performance relay nodes in realtime with low overhead and high effeciency.Based on the Windows OS and Visual.NET development enviroment, the emluator system which is coded in the C++ language simulates the construction of Internet network layer and build application overlay upon to evaluate respective performance of three intermediate relay detection algorithms. By testing them from different aspects as average hit·ratio, average startup delay, best path hit ratio and so on, the AS-aware intermediate relay detection scheme shows the performance of average hit ratio 10% to 40% higher than the other two schemes based on different scales of network, more than 30% shorter average startup delay and best path hit ratio retiains above 50% while overlay holds a large number of supernodes. It is proved that AS-aware intermediate relay detection scheme is a practicable strategy which is feasible to actualize in a real system.