Design of a distributed P2P-based content management middleware

There is an emerging need for Content Management Systems (CMS) enabling collaborative development, administration, and distribution of large amounts of content, in particular web content, which enfolds an increasing number of different types and formats of content that is made accessible over the Internet. Most of these systems are currently based on a client/ server architecture, where content storage and management are performed centrally on a dedicated server. While such centralized systems simplify the management with respect to data consistency, security, and accountability, they usually lack scalability and reliability. Pure peer-to-peer (P2P) network architectures are based on the assumption that no central server exists and has to be relied on, since every peer can (or rather needs to) participate in the provisioning of core system functionality that would be provided otherwise by a single server. A P2P-based CMS scales much better, because available system resources increase linearly with the number of participating peers. Moreover, the reliability of the system can be made very high, since the degree of system redundancy can be increased without much effort. However, compared to the centralized approach, conventional CMS tasks, such as versioning as well as access control and accounting, become more complicated in a distributed environment with potentially many replicas of the same content. This paper proposes a completely distributed P2P-based content management system in support of access control and accounting while taking into account key aspects following from the nature of distributed systems.