An effective IPv4-IPv6 translation mechanism for SIP applications in next generation networks

In a next generation network, the IPv6-enabled IP multimedia subsystem (IMS) network may connect to an IPv4 network. When an IPv4/IPv6 dual-stack user equipment (UE) initiates a call by sending an IPv6 SIP INVITE message to an IPv4-only user agent (UA), the call cannot be established correctly. To resolve this problem, the IMS-application layer gateway solution, the redirect solution, and the interactive connectivity establishment solution have been proposed. In this paper, we propose an effective solution where only the IPv6 INVITE message is translated into an IPv4 INVITE message. Upon receipt of the IPv4 200 OK message replied from the IPv4-only UA, the dual-stack UE learns that the correspondent UA supports IPv4-only and utilizes IPv4 instead of IPv6 to send the subsequent SIP messages and real-time transport protocol (RTP) packets. The proposed solution is compared with the existing solutions in terms of network node modification, call setup complexity, and RTP transmission latency. Our study indicates that the proposed solution outperforms the other three solutions in the call setup and the RTP transmission. Copyright (C) 2009 John Wiley & Sons, Ltd.