Abstract
The IP Multimedia Subsystem (IMS) is an open IP based service infrastructure that enables an easy deployment of new rich multimedia services mixing voice and data. The IMS is considered as a next generation Service Delivery Platform (SDP) on top of different wireless and wire line access networks. It is based on the Session Initiation Protocol (SIP) which is gaining more and more acceptance in the VoIP market. As an emerging technology, the SIP standard will certainly be the target of Denial of Service (DoS) attacks and consequently IMS will also inherit this problem. Therefore, it is very important to protect IMS resources from DoS threats. In this paper, we suggest an efficient solution for protecting the IMS networks from such attacks.