”P4L”: A Four Layers P2P Model for Optimizing Resources Discovery and Localization

Abstract

Peer-to-Peer systems are based on the concept of resources localization and mutualization in dynamic context. In specific environment such as mobile networks, characterized by high variability and dynamicity of network conditions and performances, where nodes can join and leave the network dynamically, resources reliability and availability constitute a critical issue. To deal with this critical issue, we introduce a new concept and model called ”P4L” (four layers Peer-to-Peer model) which define a novel P2P architecture, aims to improve: fault-tolerance, self- organization and scalability, with limited complexity while providing a rapid convergence for the lookup algorithm. The cost of ”P4L” lookup is O(∑ln (n _i )) where n _i is the number of nodes on ring level i (with maximum of 256 nodes in each ring). ”P4L” is efficiently adapted to the context where nodes join and leave dynamically and frequently. Each node maintains routing information of 2*O(ln (n _i )), where n _i is the number of nodes on one ring. Thus ”P4L” is well adapted for terminals with limited resources such as mobile terminals. ”P4L” is based on ring topology with each ring connecting ”neighbouring” nodes in terms of physical and logical position. When ”P4L” is combined with broadcast mechanism, the lookup process is significantly improved. The proposed model is evaluated and compared with Chord protocol, an extension is proposed to support IPv6.