We present the feasibility evaluation of a structured communication-oriented Peer-to-Peer (P2P) system being used in mobile environments in this paper. The different levels of churn are modeled by the exponential distribution with varied value of mean online time. Our system utilizes Kademlia with some modifications as the underlying Distributed Hash Table (DHT) algorithm, and Peer-to-Peer Protocol (P2PP), one of the former candidates of Peer-to-Peer Session Initiation Protocol (P2PSIP) working group, as the signaling protocol. A prototype is implemented to evaluate the feasibility of mobile nodes acting as fully fledged peers. The prototype measurements show it is feasible for the mobile nodes to take part in the overlay from the viewpoints of CPU load and network traffic load. Through battery measurements, we draw the conclusion that the UMTS access mode consumes slightly more power than the WLAN access mode in general. Protocol packets with sizes of 200 bytes or less are observed t...