NG9-1-1: Terms we must come to terms with

June 26, 2019 David Hamilton

What does one mean by Location-to-Service Translation protocol or LoST? What is an ESInet and how does it support NG9-1-1? NG9-1-1 comes with not just advanced technology and new public safety standards but also many new terms to add to your vocabulary.  

As we begin to start educating ourselves about the technologies that are ushering in the next generation of 9-1-1, we have already started acquainting ourselves with many new words, acronyms, processes and entities. In this blog post, I’ve tried to summarize some key terms that are commonly being used to describe the various components of NG9-1-1. This is by no means a complete list of public safety industry jargon, but more or less a beginner’s guide to the most popular terms used in relation to GIS for NG9-1-1.

  • 9-1-1 Authority

A provincial, regional or other governmental entity having administrative jurisdiction over a particular 9-1-1 system. For example, a regional district or municipal or provincial government, a special 9-1-1 or Emergency Communications District, a Council of Governments or another similar body.

  • Automatic Location Identification (ALI)

The automatic display at the PSAP of the caller’s telephone number, the address/location of the telephone and supplementary emergency services information of the location from which a call originates.

  • Automatic Vehicle Location (AVL)

A means for determining the geographic location of a vehicle and transmitting this information to a point where it can be used.

  • Computer-Aided Dispatch (CAD)

A computer-based system, which aids 9-1-1 call takers and dispatchers by automating selected dispatching and record-keeping activities.

  • Data Aggregator

The agency charged with ensuring that the GIS data provided by the authoritative data providers is aggregated into a single database used by the NGCS, PSAPs and first emergency services agencies. A local authoritative data provider is usually municipal, regional (county) and/or provincial government.

  • Dispatchable Location

A location, represented as a civic address or geographic coordinates (latitude/longitude), that contains enough detail for accurately dispatching emergency responders to the location which has been confirmed by the PSAP operator following a dialogue with the caller.

  • Emergency Call Routing Function (ECRF)

A functional element in an ESInet, which is a LoST protocol server where location information (either civic address or geo-coordinates) serves as input to a mapping function that returns information used to route an emergency call toward the appropriate PSAP for the caller’s location or towards a responder agency.

  • Emergency Communications Centre (ECC)

The entity that handles certain aspects of emergency sessions, e.g. routing of emergency requests to the correct emergency centre or PSAP.

  • Emergency Service Boundary (ESB)

A geographic area representing the dispatch responsibility of an emergency service agency.

  • Emergency Service Number (ESN)

A 3-5 digit number that represents an ESZ. It is stored in the MSAG and is returned from an ALI query. The Administrative ESN facilitates dispatching of the proper emergency service agency(ies). An Administrative ESN is assigned to each MSAG range to associate the physical addresses to an ESZ.

  • Emergency Service Zone (ESZ)  

A geographical area that represents a unique combination of emergency service agencies (such as Law Enforcement, Fire or Emergency Medical Service) that is within a specified 9-1-1 governing authority’s jurisdiction. An ESZ can be represented by an Emergency Service Number (ESN) to identify the ESZ. (Refer to ESN)

  • Emergency Services IP Network (ESInet)

A managed IP network used for emergency services communications, which can be shared by all public safety agencies. It provides the IP transport infrastructure, upon which independent application platforms and core services can be deployed, including but not restricted to, those necessary for providing NG9-1-1 services. ESInets may be constructed from a mix of dedicated and shared facilities. ESInets may be interconnected at local, regional, provincial, federal, national and international levels to form an IP-based inter-network (a network of networks). The term ESInet designates the network, but not the services that ride on the network. See NG9-1-1 Core Services.

  • GeoFoundation Exchange (GFX)

A national, collaborative, open data exchange for accurate and authoritative geographic base mapping data – see also PSGX (Public Safety GeoExchange).

  • Incumbent Local Exchange Carrier (ILEC)

A telephone company that is responsible for providing the primary 9-1-1 routing services in a geographic area. In Canada, the primary ILEC’s are Telus, Sask Tel and Bell Canada.

  • Location Information Server (LIS)

A repository of mappings between calling device reference values such as an IP address, and geographic location values.

  • Location Validation Function (LVF)

A functional element in an NGCS that is a LoST protocol server where civic location information is validated against the authoritative GIS database information. A civic address is considered valid if it can be located within the database uniquely, is suitable to provide an accurate route for an emergency call and adequate and specific enough to direct responders to the right location.

  • Location-to-Service Translation Protocol (LoST)

A protocol used generally for location-based call routing. In NG9-1-1, LoST is used as the protocol for the ECRF and LVF.

  • Master Street Address Guide (MSAG)

A database of street names and house number ranges that is used to define Emergency Service Zones (ESZs) and their associated Emergency Service Numbers (ESNs) to enable proper routing of 9-1-1 calls.

  • National Emergency Number Association (NENA)

A professional organization solely focused on 9-1-1 policy, technology, operations and education issues

  • NENA i3

NENA i3 introduces the concept of an Emergency Services IP network (ESInet), which is designed as an IP-based inter-network  (a network of networks) shared by all agencies that may be involved in an emergency.

  • Next Generation 9-1-1 (NG9-1-1)

NG9-1-1 is an Internet Protocol (IP)-based system comprised of managed Emergency Services IP networks (ESInets), functional elements (applications) and databases that replicate traditional E9-1-1 features and functions and provides additional capabilities. NG9-1-1 is designed to provide access to emergency services from all connected communications sources and provide multimedia data capabilities for Public Safety Answering Points (PSAPs) and other public safety agencies organizations.

  • Next Generation 9-1-1 Core Services (NGCS)

The base set of services needed to process a 9-1-1 call on an ESInet. Includes the ESRP, ECRF, LVF and more. The term NG9-1-1 Core Services includes the services and not the network on which they operate. See Emergency Services IP Network.

  • Originating Networks

The network which originates a 9-1-1 call. Includes the access network and the calling network. Typically, operated by carriers or other service providers.

  • Presence Information Data Format – Location Object (PIDF-LO)

Provides a flexible and versatile means to represent location information in a SIP header using an XML schema.

  • Policy Routing Function (PRF)

A functional component of ESRP that determines the next hop in the SIP signalling path using policy Provisioning Boundary Geographic area of GIS data in which a 9-1-1 authority is responsible to maintain.

  • Public Safety Answering Point (PSAP)

An entity that is responsible for receiving 9-1-1 calls and event notifications for a defined geographic area and processing those calls according to a specific operational policy.

  • Primary PSAP

A PSAP to which 9-1-1 calls are routed directly.

  • Secondary PSAP

A PSAP to which 9-1-1 calls are transferred from a Primary PSAP.

  • Public Safety GeoExchange (PSGX)

A public safety-specific software utility designed to exchange NG9-1-1 GIS data between the authoritative providers to the designated NG9-1-1 data aggregator. Key features of the PSGX utility include the following:

a) Integrity checking on the data as part of the exchange process.

b) Ability to automatically push/pull transactions or whole datasets between the provider and the integrator

c) Mechanisms to report issues to the provider and to notify the integrator of changes 

  • Service Type

A broad definition to describe different originating networks types. Examples are wireless, wireline, cable, or IP. Calls can be classified by their service type.

  • Spatial Interface (SI)

A standardized data replication interface used to publish GIS data to the functional elements that consume GIS data, such as the ECRF, LVF or Map Database Services. 

About the Author

David Hamilton

David Hamilton is the Public Safety Industry Manager for Esri Canada. His efforts are focused on advising customers how to use GIS technology to improve all areas of public safety, specifically (NG)9-1-1, law enforcement, fire services, emergency medical services, emergency management, and search and rescue. Prior to joining Esri Canada in 2010, David managed the GIS for E-Comm 9-1-1 in Vancouver, and worked for the RCMP at the Integrated Security Unit for the 2010 Olympic Winter Games where he managed their Common Operating Picture. Being active has been a major part of David’s personal life; soccer, track & field, skiing, cycling, hiking and now kayaking are all among his favourite activities… Yoga is next.

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