Interim VoIP Architecture (i2)

Document Information
Full name: 

Interim VoIP Architecture for Enhanced 9-1-1 Services (i2)

Document type: 


Standard number: 

08-001 v2

Document description: 

Voice over Internet Protocol (VoIP) is poised to become the predominant technology used in the telecommunications industry. As the public adopts VoIP, E9-1-1 calls will increasingly originate from VoIP users. Some VoIP telecommunications service provider networks, however, are not natively compatible with the existing E9-1-1 infrastructure. This document was developed to outline an interim architecture to connect callers in the IP domain with Public Safety Answering Points (PSAPs) supported by the existing E9-1-1 Service Provider network.

This document is the NENA recommended standard for the i2 architecture to support the interconnection of VoIP domains with the existing Emergency Services Network infrastructure in support of the migration toward end-to-end emergency calling over the VoIP networks between callers and PSAPs.

This document provides an overview of the VoIP architecture, functional elements, and interfaces, as well as the interface specifications necessary for interconnection with the existing Emergency Services Network infrastructure.

This document does not include specifications for the methods used to determine location nor how the endpoint actually receives location.

VoIP is being introduced into the North American environment by VoIP Service Providers (VSPs). NENA and a number of the VSP’s acting through the Voice on the Net (VON) Coalition reached agreement to support current NENA and industry work towards long-term solutions that include (a) delivery of 9-1-1 calls to the proper PSAP; (b) providing callback number/contact information to the PSAP; (c) providing the location of the caller; and (d) PSAPs having direct IP connectivity. The initial standards development work of the NENA VoIP/Packet Committee was to be completed by the end of 1Q05. This architecture embodies that initial work.

This recommended standard is being provided to facilitate the development and implementation of interoperable, standard equipment and processes to support VoIP emergency services calling throughout North America. 

Use of this document will:

  • Ensure that equipment and service providers that conform to these recommendations will have a solution that is interoperable,
  • Foster development of network elements and processes that can be reused in the architecture that supports end-to-end IP calling to the PSAP.
Committee Information
Committee Name(s): 

Technical – VoIP/Packet

Committee type: 


Document Dates




Document Size
20100811_08-001 v2.pdf 1.81 MB