The Research Of Relay Selection Algorithm And Security Mechanisms For P2P VoIP

With the increasingly widespread use of P2P VoIP, its QoS requirements are also rising. How to improve the P2P VoIP QoS, especially to shorten the session delay has become a hot research point of P2P field. Researches have shown that there is an anti-triangular network phenomenon, namely, the latency of overlay routing path through relay node sometimes is shorter than the direct IP-routing path. So it is a method to shorten the delay of P2P VoIP session by building overlay routing through selecting appropriate relay nodes in the P2P network. Based on that, a distributed relay selection algorithm based on meridian algorithm which is called MBRS (Meridian-Based Relay Selection) is proposed in this paper.IETF (Internet Engineering Task Force) has been committed to the standardization of P2P traffic for long time. ALTO (Application-Layer Traffic Optimization) is a standardization working group whose object is to optimize the P2P traffic. ALTO server can provide the traffic guidance and node selection services for clients. In this paper, a P2P network telephone system is designed combined with the feature of ALTO and MBRS algorithm. It provides a prototype system architecture in which the MBRS algorithm is used.Because the relay node is used to relay communication data for the source and destination, its security will directly affect the security of communication data. Therefore, some security measures must be considered when selecting relay nodes. In this paper, some available security mechanisms are proposed aiming at the possible security threats of relay nodes. These mechanisms are also developed and implemented to verify their feasibility.