ABSTRACT: This document addresses the functions, interfaces, and data that must be supported by a Legacy Selective Router Gateway to facilitate the interconnection of i3 Emergency Services IP Networks (ESInets) with legacy SRs and Internet Protocol Selective Routing (IPSR) functional elements. The purpose is to support the routing of emergency calls to the appropriate Public Safety Answering Point (PSAP).

GR-3170 is the only public document that fully describes the functionality, interfaces, and operations requirements associated with a Legacy SR Gateway. It addresses the following:

• Requirements on the Legacy SR Gateway to accept and process emergency call requests from legacy SRs and IPSRs associated with wireline and wireless emergency call originations
• Requirements for VoIP emergency call originations that are routed via i2 Solution-based VoIP Service Provider (VSP) networks to a legacy SR or IPSR, and are destined for an i3 PSAP that is served by an ESInet
• Requirements on the Legacy SR Gateway to use information received in incoming signaling to obtain and use location information as input to a routing determination process
• Requirements to interwork the incoming SS7 signaling from legacy SRs with outgoing SIP signaling appropriate for the Emergency Services Routing Proxy (ESRP) in the i3 ESInet through which the call is to be routed
• Requirements to accept and process emergency call originations routed via elements of the i3 ESInet and destined for a PSAP served by a legacy SR or IPSR
• Requirements to support location/Automatic Location Identification (ALI) data delivery to the target PSAP
• External signaling interfaces that must be supported by the Legacy SR Gateway
• Operations, performance and security requirements on the Legacy SR Gateway.