There are many Peer-to-Peer (P2P) networks in literature which are designed to provide collaboration and sharing as well as active router to enhance the routing process. However, there is no any single-node architecture that integrates P2P network and active router architecture. This book is aimed at proposing a single-node architecture that integrates both active routing and P2P networking. In this book, four different case studies are implemented using P2P networks. These studies are communication, security, routing based content and scheduling applications. Each case study was evaluated and tested. Communication applications include unicast (ping and deliver) and multicast (cast and broadcasting) applications. The security applications include active firewall and active protection. For the routing based content application, the delay time for packet flow increase with the increase of the number of hops or size of varValsend() function. Scheduling applications are based on two search mechanisms, depth first search (DFS) and breadth first search (BFS).