Infrastructures for Community Networks

Content delivery has undergone a sea of changes in recent years. While even only ten years back the major delivery channels were television and radio broadcast, nowadays content is delivered digitally via the Internet or other electronic delivery channels. The engineering problem of delivering multimedia content through the Internet has received much attention by the research community. However, the delivery of content to heterogeneous mobile terminals in a community context still poses many problems. Early Internet based content delivery systems were designed as centralized systems where content is provided from a central server to a large population of the end users (see Fig. 15.1-(a)). This trend is now shifting towards decentralized systems, such as Peer-to-Peer (P2P) systems, in which the role of the content provider and producer is no longer restricted to a few professional content creators. Thus, the content delivery paths is not anymore only from a central server through backbone networks to the end users, but also from one end user to other end user(s) (see Fig. 15.1-(b)). This has been triggered by the emergence of relatively cheap consumer electronics enabling everybody to become a content producer; and