Legacy 911 to ng9-1-1 Network

Document Outline

• Legacy 911 to NG9-1-1 Network
• Through MN 403, the Department of Public Safety Commissioner is responsible for the maintenance of the 911 network. The 911 network’s primary function is to take the location of a 911 caller, identify which PSAP the call should be routed to and connect the caller to the call taker or dispatcher. 911 turned 53 this year and has been forced to apply band-aid solutions to its routing workflows to accommodate cellular devices. An upgrade to the 911 network plays a prominent roll in the current SECB strategic plan and is currently being implemented by ECN. A high level overview of this transition is detailed below with a glossary of terms and corresponding acronyms on the back.
• Legacy 911
• The legacy 911 network routing workflow was engineered at a time when the only means of calling someone was on a wired landline. The location of 911 callers was fixed at a home or office and tied to one device. The legacy system currently uses tabular location databases and can successfully route wireline, VOIP and wireless callers.
• NG9-1-1
• With advanced in technology and the aging infrastructure, anew architecture, NENA’s i model, was published 10 years ago. This new architecture relied upon IP technology to transmit the calls but would also allow for the transmissions of texts and ultimately video to be sent to the dispatch center. This network overhaul is comprised of three parts the ingress network, the next generation core services and the egress network.
• Ingress Network The purpose of the ingress network is to prepare 911 calls for location identification. The components in this network connect originating service providers (wireline, VOIP or wireless) and if needed, convert the call into an IP format. The location of the caller is then ready for transmission to the NGCS.
• NGCS: The NGCS play two functions – 1) identify the PSAP who is the primary call center for this location (either via geoverification or policy based routing) and 2) validate that anew wireline or VOIP service location is a valid 911 address. Gone are the tabular location databases found in the legacy 911 call routing networks (MSAG and ALI, this functionality is now replaced by highly-accurate, locally sourced GIS data.
• Egress: Once the NGCS has provided the recommendation on which PSAP the call is routed to, the egress network takes on the transporting of the caller to that dispatch center. Some call this the last mile network or the ESInet.
• The spirit of NG9-1-1 i architecture is to create a competitive market that encourages multiple solution and service providers who contract for these network components. This is a change in how 911 operates as a business but also presents some new challenges. Traditionally 911 services have been provided by one vendor this includes the monitoring of the network for service disruptions. Minnesota plans to implement end-to-end network monitoring to include monitoring all three components of the NG9-1-1 call routing network. This will provide to stakeholders at the local, regional and state levels a single point of contact to report and be alerted by when an issue occurs in the 911 call flow to the PSAP.
• NG9-1-1 Glossary of Terms and Acronyms
• Definition
• Term/Abbreviation
• A functional element in an NGCS (Next Generation 9-1-1 Core Services) which is a LoST protocol server where location information (either civic address or geo-coordinates) and a Service URN serve as input to a mapping function that returns a URI used to route an emergency call toward the appropriate PSAP for the caller’s location or towards a responder agency.
• ECRF (Emergency Call Routing Function) NGCS
• A managed IP network that is used for emergency services communications, and 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 maybe constructed from a mix of dedicated and shared facilities. ESInets maybe interconnected at local, regional, state, federal, national and international levels to form an IP-based internetwork (network of networks. The term ESInet designates the network, not the services that ride on the network.
• ESInet (Emergency Services IP Network)
• An i functional element which is a SIP proxy server that selects the next hop routing within the ESInet based on location and policy. There is an ESRP on the edge of the ESInet. There is usually an ESRP at the entrance to an NG9-1-1 PSAP.
• ESRP (Emergency Service Routing Proxy) NGCS
• NENA i introduces the concept of an Emergency Services IP network (ESInet), which is designed as an IP-based inter-network (network of networks) shared by all agencies which maybe involved in any emergency.
• i3
• A server that retains all of the current information, functionality, and interfaces of today’s ALI and can utilize the new protocols required in an NG9-1-1 deployment.
• LDB (Location Database) NGCS
• An NG9-1-1 Functional Element that provides an interface between a non-IP originating network and a Next Generation Core Services (NGCS) enabled network.
• LNG (Legacy Network Gateway) Ingress
• LSRG (Legacy Selective Router Gateway) Provides an interface between a 9-1-1 Selective Router and an ESInet, enabling calls to be routed and/or transferred between Legacy and NG networks. A tool for the transition process from Legacy 9-1-1 to NG9-1-1.
• LSRG Ingress
• 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.
• LVF (Location Validation Function)
• The base set of services needed to process a 9-1-1 call on an ESInet. Includes the ESRP, ECRF, LVF, BCF, Bridge, Policy Store, Logging Services and typical IP services such as DNS and DHCP. The term NG9-1-1 Core Services includes the services and not the network on which they operate.
• NGCS (Next Generation 9-1-1 Core Services)
• A protocol specified by the IETF (RFC) that defines a method for establishing multimedia sessions over the Internet. Used as the call signaling protocol in VoIP, NENA i and NENA i3.
• SIP (Session Initiation Protocol)
• A standardized data replication interface used to publish GIS data to the functional elements that consume GIS data, such as the ECRF, LVF, Map Database Services, etc.
• SI (Spatial Interface)
• The Central Office that provides the tandem switching of 9-1-1 calls. It controls delivery of the voice call with ANI to the PSAP and provides Selective Routing, Speed Calling, Selective Transfer, Fixed Transfer, and certain maintenance functions for each PSAP.
• SR (Selective Router)
• The process by which 9-1-1 calls/messages are routed to the appropriate PSAP or other designated destination, based on the caller’s location information, and may also be impacted by other factors, such as time of day, call type, etc. Location maybe provided in the form of an MSAG-valid civic address or in the form of geo coordinates (longitude and latitude. Location maybe conveyed to the system that performs the selective routing function in the form of ANI or pseudo-ANI associated with a pre-loaded ALI database record (in Legacy 9-1-1 systems, or in real time in the form of a Presence Information Data Format – Location Object (PIDFLO) (in NG9-1-1 systems) or whatever forms are developed as 9-1-1 continues to evolve.
• Selective Routing