Extending P2PSIP VoIP communication for ad hoc networks

In this paper, we modify and extend the P2PSIP's lead-ing draft (RELOAD) in order to both adjust its operation better with respect to the properties of wireless ad hoc net-works 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 be-tween the peers, while symmetric cryptography is used pri-marily 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 pro-tocol, and the Semi-Hierarchical RELOAD (SHR) that fol-lows the same logic with HR but also permits, for a limited time window, a more distributed operation for the proto-col. We evaluate the proposed protocols in comparison to RELOAD, and the results show that HR produces consider-Ably 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 ad-ditional cost.