Content distribution infrastructures for community networks
Multimedia content delivery has undergone dramatic changes in recent years. The roles of content providers and producers are no longer restricted to a few professional organisations since more and more users share audiovisual content or use community sites to support their common interest. Nowadays both portable multimedia devices (e.g. PDAs, mobile phones, MP3 recorders, and digital cameras) and home entertainment systems (e.g., set-top boxes, game consoles, and media-centres) have become integral parts of the content production and distribution chain. Further, the underlying delivery infrastructure is undergoing major changes. There is a shift away from the traditional client/server model to systems based on the peer-to-peer paradigm, which let users share computational, storage and bandwidth resources. Moreover, the physical infrastructure is evolving towards some form of spontaneous cooperation of technologies to support the creation of wireless ad hoc networks or wireless community networks. Thus, the well known engineering problem of delivering multimedia content through the Internet is evolving into the problem of how to dynamically create content distribution infrastructures and services. The above considerations motivated us to promote this Special Issue of ‘‘Computer Networks”. The specific purpose of it is to present recent advances in the study of content distribution infrastructures from a networking perspective. The many submissions we received were evenly spread over different areas and showed how relevant and timely the topic of this special issue is. Out of sixty-five submitted papers, nine were selected considering their quality and relevance for the topic of the special issue. The articles selected for this special issue can be grouped into three different research themes – (i) articles dealing with different issues related to application domains such as peer-to-peer streaming, (ii) articles presenting analysis and measurements of content distribution networks, and (iii) articles presenting research into overlay network design and new concepts for content network overlays. More specifically these are: