Research Of SIP Internet Based On P2P

P2P technology and SIP protocol are two of tho三se most popular topics in Internet and telecommunication at present.The P2P system's self-organization,high scalability,robustness and fault tolerance features bring a revolution of copute pattern to the whole IT world.At the same time, SIP is a signaling protocol in application layer for creating,managing and terminating multimedia sessions over IP network.It is now gradually becoming the key protocol of NGN and 3G Multimedia subsystem with it's excellence of simpleness,easy extension and implement,but it's based on the C/S architecture.Thus,how to enhancing the reliability of SIP network and making full use of terminal resource with the P2P technology is becoming one of research focuses on SIP network.This paper analyzes the architecture and characteristic of SIP network, SIP protocol stack and SIP message,studies the logical topology and routing lookup of Chord resource locating algorithm.Some problems about SIP network introducing P2P technology for resource locating are included.First of all,for the P2P-SIP terminals's heterogeneous nature and the finger table's redundancy of Chord node,DHChord,a double hierarchical resource locating model of Chord is proposed,in which the upper and lower layer both are structured Chord network,each group being self-governed Chord ring by its delegate.The requests,such as routing and query operations beyond their own groups,are completed by the aid of super nodes in the upper Chord ring.Every node makes use of the reduced routing table for storage of efficient information.It achieves the goal of reducing the maintenance overhead,improving the lookup effectiveness by only adding little load to some super nodes but dereasing finger table's length for most nodes.Secondly,in order to choose the appropriate hierarchical Chord model for P2P-SIP network,the paper presents an analytical approach for hierarchical Chord model on cost performance.It provides the theoretical basis for that the DHChord is superior than the normal Chord model on the cost traffic.What's more,we determine the optimal operating point of the analyzed architectures.Based on the network traffic at the optimal point,it allows to compare the analyzed hierarchical system designs and to decide which one is best on the total network traffic and superpeer total network traffic for heterogeneous environments.The result provides the theoretical basis for determining which hierarchical Chord model to be used in the P2P-SIP network according to the practical application.Finally,a hierarchical P2P-SIP network system and the node's logical structure are designed.The P2P-SIP message,registration disposal,user rearch and session establishment are analysed in details.What's more,the P2P realization of SIP protocol is designed based on the MjSip open source protocol stack.This work proposes an improved Chord resource locating algorithms, the P2P extension of SIP protocol and design of hierarchical P2P-SIP network.It enhances the high scalability,robustness and fault tolerance of SIP network.