scope:

The evolution of emergency services will occur in originating networks (wireline, wireless, cable, etc.) and within the core emergency services network(s) based upon relevant standards. While 3GPP and 3GPP2 have evolving standards that focus on emergency services in originating networks, only NENA has standards activities that address the evolution of the IP based emergency services network(s). The NENA standard development activity does not take into account the nuances of the development of the ATIS Next Generation Network (NGN). The ATIS NGN documents do not take into account (to any depth) the needs of a next generation emergency services network.

This Technical Report (TR) addresses a carrier centric approach to the evolution to next generation emergency services networks and uses the ATIS NGN architecture as the basis for the network evolution. An Emergency Services Next Generation Network (ES-NGN) enables the evolution of the legacy circuit switched E9-1-1 emergency services network into an IMS based next generation network that can support existing functionality and allow new modes of communication that facilitate new services and capabilities. These may be introduced based upon emerging technologies that allow enhancements such as delivering video, graphics, messaging, etc. This TR focuses on gaps related to the Network-to-network Interconnection (NNI) between the ES-NGN and other networks originating emergency calls, and to the PSAP. Those networks may be legacy networks or emerging packet-based networks.

Purpose and Applicability

The purpose of this Technical Report is to help guide standards activity related to an emergency services network evolving toward a next generation emergency services network focused on North America. This Technical Report identifies standards that are applicable to an Emergency Services Next Generation Network (ES-NGN) under the umbrella of the ATIS NGN framework. This TR also identifies gaps in standards activity that is needed to facilitate the definition and realization of next generation emergency services. This TR suggests harmonizing the functions described in the NENA ESInet and the ATIS NGN as they apply to emergency services.

Concept Architecture

The Emergency Services Next Generation Network is an evolution of legacy emergency services telecommunications (i.e., E9-1-1) into the technologies defined as part of ATIS NGN. The ES-NGN will replace legacy emergency services networks in a transitional model that will occur over a period of several years. Figure 1-1 represents a concept architecture showing that the ES-NGN must operate with legacy networks and the evolving networks that provide advanced services and capabilities. The Emergency Services Next Generation Network is similar in function to the NENA defined Emergency Services IP Nework (ESInet). As shown in Figure 1-1 the definition of 1) the ingress to the ES-NGN, 2) the ES-NGN itself, 3) the egress to the legacy Selective Router, 4) the egress to the IP PSAP and 5) egress to legacy PSAPs are within scope of this Technical Report.

Because originating telecommunications networks will evolve at their own paces, the ES-NGN must accept calls from existing legacy originating networks. Those legacy networks may be traditional wireline, wireless, cable, VoIP Service Providers (VSP) operating in a NENA i2, or pre-i2 environment, etc. Those calls will enter the ES-NGN via the Legacy Network Gateway (LG) shown in Figure 1-1. The ES-NGN also must accept calls from the next generation packet-based networks operating under the standards of NENA's i3, 3GPP's IMS, etc. These networks may be wireline, wireless, Fixed Mobile Convergence (FMC) networks, etc. These networks will deliver calls to the ES-NGN via a Session Border Controller (SBC) in a native packet mode and may also include the subscriber location in the call request.

ES-NGN must be able to deliver emergency calls to IP-enabled PSAPs via a SBC as well as to legacy PSAPs via a Legacy PSAP Gateway (LPG). IP-enabled PSAPs will have the ability to receive emergency calls in a native packet mode which will include the subscriber location information in the call request. The definition of "emergency call" is expanded to include the delivery of text, graphics, video and access to other advanced services.

Because the ES-NGN will be introduced while there are still existing legacy emergency services networks in operations, the ES-NGN must be able to interact with these networks via the Legacy Selective Router Gateway (LSRG). For example, there may be a need to bridge or transfer calls between IP-enabled PSAPs and legacy PSAPs homed on the legacy emergency services network. Also, there may be the need to alternate route calls destined toward IP-enabled PSAPs to legacy PSAPs, and visa versa, due to network outages, night closure and other applicable business policies.