The integrity, confidentiality, and availability of Emergency Telecommunication Service (ETS) in a multi-provider Next Generation Network (NGN) environment will depend on the security of each individual network involved in an end-to-end communication. To allow network provided security of end-to-end ETS communications in a multi-provider environment, intra-network domain and inter-network domain security requirements for ETS protection are needed. This standard provides a minimum set of common (i.e., independent of network type or technology) and core network security requirements for the protection of ETS in a multi-provider NGN environment.