Extending P2PSIP VoIP Communication for Ad Hoc Networks

In this paper, we modify and extend the P2PSIP's leading draft (RELOAD) in order to both adjust its operation better with respect to the properties of wireless ad hoc networks and improve the provided security level. In terms of security, a public/private key infrastructure scheme is used along with a symmetric cryptographic mechanism. Public key cryptography is used to encrypt the communication between the peers, while symmetric cryptography is used primarily for authentication purposes. The public/private key pair of each peer is periodically refreshed to further improve the security level of the system. Two schemes are proposed: the Hierarchical RELOAD (HR), where the Bootstrap peers are central to all the operations implemented within the protocol, and the Semi-Hierarchical RELOAD (SHR) that follows the same logic with HR but also permits, for a limited time window, a more distributed operation for the protocol. We evaluate the proposed protocols in comparison to RELOAD, and the results show that HR produces considerably lower communication overhead within the peer-to-peer network than both RELOAD and SHR, with the latter's however more flexible network operation justifying the additional cost.