This document addresses VoP/Multimedia signaling and control plane security requirements of evolving telecommunications networks. Evolving telecommunications networks often combine legacy telecommunication facilities with new technologies such as Wireless (air interface)@ ATM@ and Internet Protocol transport mechanisms. The security requirements given in this document apply to service provider networks and may also be applicable to individual company corporate enterprise networks. The scope of this document is specifically security requirements for the Network to Network Interface (NNI) between similar or dissimilar VoP/Multimedia networks. This document aligns with the organization and framework provided by ITU-T Recommendation X.805@ Security Architecture for Systems Providing End-to-End Communications. [X.805]@ and existing security standards are referenced and specified as appropriate. NOTE -- Endpoints for example user terminal to user terminal peer to peer signaling across the NNI is not within the scope of this document Purpose This document provides baseline security requirements to address security for VoP/Multimedia applications using H.323 and SIP. The purpose of this document is to specify security requirements for the VoP/Multimedia signaling and control plane functions of evolving telecommunications networks@ to allow secure interoperability of equipment from multiple vendors by providing signaling and control plane security requirements to carriers and vendors.