Improving the Fixed-Line Access Security for IMS

IP multimedia subsystem (IMS) is an open architecture to provide multimedia service based on IP network, it has already been widely accepted as the core of next generation network (NGN). As IMS has the feature of IP-based and independence of access technology, in fixed-line access environments, P-CSCF will be directly exposed to UEs, which brings security challenges for IMS compared with the traditional telecommunication network. This paper gives a detailed analysis of fixed-line access security problems in IMS, and gives a solution of countermeasure, a new entities of ASCF and a new reference point of Gm´ are defined, which enhance the fixed-line access security for IMS in both signaling and media level.