Security in Carrier Class Server Applications for All-IP Networks
  A revolution is taking place in telecommunication networks. New services are appearing on platforms such as third generation cellular phones (3G) and broadband Internet access. This motivates the transition from mostly switched to all-IP networks. The replacement of the traditional shallow and well-defined interface to telephony networks brings accrued flexibility, but also makes the network accordingly difficult to properly secure. This paper surveys the implications of this transition on security issues in telecom applications. It does not give an exhaustive list of security tools or security protocols. Its goal is rather to initiate the reader to the security issues brought to carrier class servers by this revolution. 
Marc Chatel, Michel Dagenais, Charles Levert, Makan Pourzandi