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The general peer-to-peer based service system formed as an overlay network on top of the underlying physical computer network and the overlay network can be distinguished with the hybrid peer-to-peer network or the pure peer-to-peer network in terms of their centralization and structure. Because of no central server, the pure peer-to-peer network can release the server management cost, the single point of failure problem, the traffic overload or the scalability problem. Regardless of this kind of advantages, the pure peer-to-peer network has the critical problem in the case of that if the peers known to have the requested shared resource is temporary offline, there is no way to connect or to send a request to that peer because there is no central server. In this paper, we proposed the asynchronous peer-to-peer service extension method using email server in pure peer-to-peer networking environment. According to this method, it is possible to provide the peer-to-peer services not only when the two edge peers are online but also when one of the edge peers is temporary offline. Therefore, the proposed method can be used to increase the service availability of the small-sized peer-to-peer network in which the shared resources are not guaranteed to be always available. Also, the proposed method can be effective for the mobile network in which mobile device is not always online.

To ensure continuity of a UPnP A/V session following a user's movement trajectory in the home, we designed a RFID-based UPnP A/V session manager. It automatically detects a user's movement with an RFID reader, and captures or restores the states of playing A/V contents using the UPnP AVTransport service which defines a common model for A/V transport control. We present the functions and control flow operation of the designed session manager, and describe how its state is changed by the event messages generated by an RFID reader or its internal timer, and explain an algorithm for controlling access of multi-users at the same time.

In this paper, we suggest a strong peer authentication algorithm that authorizes the peer which requests a service usage of the other peer in super peer based P2P network environment. The proposed peer authentication method, at which public key certificate (PKC) and Kerberos authentication mechanism is applied, enables each peer to perform strong mutual authentication in P2P network environment. The peer mutual authentication is performed by getting authentication ticket and verification it by other peer. Also, the lifetime of a ticket can be controlled by the peer providing services according to each service.