Analyzing and Optimizing Skype Peer-to-Peer System

With conspicuous properties such as NAT traversal and better voice quality, Skype is explosively developed. Despite of the great popularity, little is known about the traffic characteristics and network architecture of Skype peer-to-peer system attributed to proprietary protocol. We devote to shed light on Skype by parsing the protocol on basis of corresponding experiments and locate the most crucial problems of Skype system: the searching delay and end-to-end delay. In order to improve the system performance, we firstly present novel algorithm for ONs to join super node with awareness of the underlying geographical distance and relationship proximity. Secondly, we build routing-efficient SN overlay network based on small-world model by selecting the short and long links dependent on distance measured by location and relationship proximity. From mathematical analysis, the proposal is proved to be preferable and the searching delay in SN network can be decreased by tuning the number of long distance links.