The scope of this standard is to define the User to Network Interface Signaling Security requirements. The standard addresses security requirements for voice over packet and multimedia security@ including: ? SIP Signaling. [RFC 3261] ? H.323: Packet-based multimedia communications systems. [ITU-T H.323] o H.225: Call signaling protocols and media stream packetization for packet-based multimedia communication systems. H.225 includes the RAS: Registration@ Admission@ Status protocol. [ITU-T H.225.0] o H.245: Control protocol for multimedia communication. [ITU-T H.245] This standard 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)@ Asynchronous Transfer Mode (ATM)@ and Internet Protocol (IP) transport mechanisms. The security requirements given in this standard apply to service provider networks and may also be applicable to individual company single location and corporate enterprise multi-location networks. This standard takes the following into consideration: ? Network operators may not always have complete control with respect to which terminal the user uses to connect to the network@ and thereby its capabilities with respect to security may not be known. ? The user may use a separate access provider network. ? There may be differences in security depending on the access technology used to connect the user to the network. This standard concerns the user to network interface (UNI) of evolving networks. For this standard@ the UNI is defined as the interface between a VoP/multimedia end user device or terminal and the network that provides service to the device or terminal. Management and Bearer Plane Security issues are outside the scope of this standard. As illustrated in Figure 1@ this standard is part of a series of related signaling and control plane security standards.