Emergency Services Gateway (ESGW) Generic Requirements
Document Number GR-3129
Issue Number 02
Issue Date Dec 2007
ABSTRACT: Issue 2 of GR-3129, Emergency Services Gateway (ESGW) Generic Requirements, replaces Issue 1.
GR-3129 provides generic requirements for an Emergency Services Gateway (ESGW) to support the routing of VoIP-originated 9-1-1 calls
to legacy PSAPs via traditional Emergency Services networks. The document includes:
- Functional requirements for the ESGW to support trunk/media gateway functionality
- Functional requirements for the ESGW to support signaling gateway functionality
- Signaling/Interface requirements
- Operations, Maintenance, and Performance requirements.
The Emergency Services Gateway (ESGW) is a critical element of the i2 Solution defined by the National Emergency Number association
(NENA) for supporting 9-1-1 call originations from VoIP customers. This document defines the required functions and interfaces that
must be supported by the ESGW to facilitate the routing of emergency calls to the appropriate PSAP via the appropriate Selective
Router, based on the caller's location. Without the ESGW component, VoIP emergency calls will continue to be routed to non-emergency
lines, as they are today, causing delays in services to VoIP callers and impacting Public Safety call answering policies and
The information contained in this document will assist developers, manufacturers and suppliers in providing a NENA i2
Solution-compliant ESGW. It will also assist potential ESGW operators in identifying required functions and in developing
implementation plans. Providers of interconnecting elements (e.g., Call Servers/Proxies, Selective Routers) will be able to develop
compatible interfaces, and ESGW suppliers and operators will be assisted in designing interoperability testing plans. ESGW providers
may see increased revenue by providing accurate routing of VoIP emergency calls. PSAPs will benefit from this document by delivering
timely and accurate VoIP emergency calls.
Issue 2 of GR-3129-CORE includes:
- Modifications to describe procedures related to the replacement of 10-digit North American Numbering Plan (NANP)-formatted
Emergency Services Routing Numbers (ESRNs) with Emergency Routing Tuples (ERTs) and Emergency Services Gateway Route Identifiers
(ESGWRIs), and support for the delivery of 10 (e.g., Emergency Services Query Key [ESQK] only) versus 20 (i.e., ESQK and callback
number) digits of information to the Selective Router with a VoIP customer-originated emergency call
- Modifications to align the terminology used in this GR with the terminology used in the draft update to NENA 08-001
- Updates to clarify the role of the VoIP Service Provider (VSP) in obtaining the necessary ESGWRI information from the ESGW provider
to support ERT-to-ESGWRI mappings
- Updates to clarify the relations between the E9-1-1 System Service Provider/SR operator and the ESGW operator to ensure that the
ESGW has accurate mappings of ESGWRIs to outgoing trunk groups, and to correctly provision the trunk groups so that the appropriate
signaling is delivered to the Selective Router with emergency calls
- Updates to bring the v4 interface definition into alignment with the current definition provided in the draft update to NENA
This document is the only public document that fully describes the functionality, interfaces, and operations requirements associated
with an ESGW.
This GR also includes one or more Issue List Reports (ILRs) that detail open or closed technical issues in the main document. The
ILR(s) are automatically sent free of charge to the GR document purchaser.
Components of this product are:
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