User freedom: To be or not to be a ‘supernode’

摘要

Peer-to-peer infrastructures in a world where many systems are mobile, or found behind NATs and firewalls that cannot be programmed by users, require significant support from computers with appropriate connectivity, called supernodes. We introduce a new fully decentralized unstructured peer-to-peer (P2P) approach to open-source instant messaging systems (that is employed in the DirectDemocracyP2P system). Here each human owning a peer can control the traffic supported by her system. The control may be based on criteria such as: (a) her desire to help the endpoints of the communication based on friendship, (b) her desire to help a cause based on the content/topic of the communication, (c) reputation and rewards, or (d) her interest in the handled data itself. Providing intrinsic incentives for peers to help with traffic is important in order for an open-source freeware P2P system to eventually be viable. In non-incentive P2P systems like Skype, availability of open-source versions can potentially starve the system of supernodes (once users learn how to disable the resource consuming supernode-function). This paper analyzes key functions of the solution such as integration of incentive management into an extension of the STUN protocol, connection establishment and message transfer under different network setups. We show how to use the results of surveys, in conjunction with simulations, to quantify the effects of various incentives on the survivability of an open approach.