Editorial: Special issue on mobile P2P networking and computing

Peer-to-Peer networking first emerged as an overlay technique to support distributed file sharing over the Internet. Since then, P2P networking and computing have gradually evolved into a system framework that delivers a broad range of distributed and scalable resource discovery and sharing applications including efficient search of data items and people using context/key based routing, application level multicast, redundant storage, video streaming, etc. Striving for automated formation, distributed operation and effective resource sharing, peers form self-organizing overlay networks and offer services beyond the traditional client-server paradigm of Internet by entrusting symmetry in roles and requiring no or fewer pre-established servers. Today, mobile end devices are one of the major participants in information gathering, processing, dissemination and consumption. Supporting the P2P networking and computing paradigm in this ever growing mobile communications environment has become an appealing idea. The key attraction of the Mobile P2P (MP2P) paradigm is its ability to scale without requiring expensive and manually configured servers, and to sustain failure points through automatic recovery of a fully distributed structure. Compared with wired networks, it is generally more difficult to set up and maintain centralized servers in some mobile networks, such as in the Mobile Ad hoc Network (MANET). It may also be generally possible to harvest efficiency gains through sharing applications and contents among peer mobile end devices directly rather than backhauling them to a centralized server in the fixed backbone network. Though the P2P paradigm may naturally suit well the distributed and dynamic wireless communications environment, support of MP2P is particularly challenging considering the special characteristics of the mobile networks. The highly variable connectivity, frequent disconnection, locationdependency, energy and resource constraints, diversity in wireless end devices and as well the carrier-grade performance requirements when offering business level applications bring about some critical issues in facilitating the MP2P paradigm. The mobility of the users may increase dramatically the churn in the peer systems to engender extra overhead when employing P2P overlay protocols. The limited bandwidth and constrained battery resource available to the wireless device aggravate the hindrance and may even render the P2P overlay mechanism infeasible in operation. Due to resource limitations, mobile peers can be inclined to the selfish freerider behaviour in data sharing and downloading. The Peer-to-Peer Netw Appl (2009) 2:179–181 DOI 10.1007/s12083-009-0040-z