A performance study for IPv4-IPv6 translation in IP multimedia core network subsystem

摘要

A Next Generation Network (NGN) is an advanced, packet-based network that exploits broadband and QoS-enabled transport technologies for enabling multimedia services. In NGNs, the principles and requirements of IP Multimedia Sub-system (IMS), which are used to deliver the desired benefits, should be carefully examined and studied. Internet Protocol version 6 (IPv6) is adopted by Third-generation Partnership Project (3GPP) to solve address storage problem and provide new features (e.g. plug-and-play and mobility) for IMS. However, in the early stage of IPv6 deployment, the existing Voice-over-IP (VoIP) networks support Internet Protocol version 4 (IPv4) only. For IPv4-IPv6 interworking between IMS and the existing VoIP networks, the IMS-Application Level Gateway (IMS-ALG) and the Transition Gateway (TrGW) are proposed to translate Session Initiation Protocol (SIP) and Real-time Transport Protocol (RTP) packets, respectively. In this paper, we focus on the IPv4-IPv6 translation for RTP packets, which is the bottleneck of VoIP performance. Specifically, we developed a TrGW called National Information and Communications Initiative (NICI)-TrGW. In NICI-TrGW, we perform IPv4-IPv6 translation at the Linux kernel and adjust the header room of kernel-level packet buffer for each packet to reduce memory-copy operations. We evaluate the performance of NICI-TrGW and the existing solutions by using the SmartBits. Our study indicates that NICI-TrGW outperforms the existing solutions in terms of three different output measures including packet loss rate, maximum throughput, and average latency.