Presentation on theme: "VoIP i2 Architecture Part II"— Presentation transcript:
1VoIP i2 Architecture Part II SBC – Southwest Public SafetyVoIP i2 Architecture Part II9-1-1 Call Routing
2The Interim VoIP Architecture for Enhanced Services (i2) document was the primary source of information used to create this presentation.This NENA STANDARD is published by National Emergency Number Association (NENA) as a guide for the designers and manufacturers of systems that are used for the purpose of processing emergency calls.
3IntroductionVoIP i2 Architecture Part II Call Routing is Part II in the VoIP series.It is important that you have reviewed Part 1: VoIP i2 Architecture - The IP Domain, prior to viewing this presentation to gain an understanding of the components in the VoIP architecture and the definitions of the acronyms used.Now here’s a step-by-step look at a 9-1-1VoIP Call Flow
5Basic Call Routing of a VoIP Emergency Call GOT IT?Now the next slide also has the IP Call Flow graphically depicted. But on this slide you can click on any of the indicated steps in the call flow for a closer look at that particular step.
7Step 1 – LO and/or LKUser AgentEndpointClick on picture to see animationV0 interfaceLISLO/LKThe LO/LK is downloaded from the Location Information Server (LIS) to the endpoint by the Dynamic Host Configuration Protocol (DHCP) server, using the V0 interface.Click on this button to return to the diagram
8Step 2 – Call InitiationCall serverUser AgentEndpointV1 interfaceLOThe VoIP endpoint originates an emergency call by sending a call initiation request, designating as the target destination, and including Callback information, and the LO using the V1 interface.
9Step 3 – QueryCall serverRouting requestVPCV2 interfaceThe Call Server receives the call initiation request and sends a routing request to the VPC using the information received in the call request over the V2 interface.
10Step 4 – Query (LK) Step 5 – Response (LO) VPCLocation KeyLISV3 interfaceLocationThe VPC queries the identified LIS over the V3 interface, including the received location key.The LIS returns to the VPC the LO it has associated with the Client-ID.
11Step 6 – ResponseCall serverVPCV2 interfaceLocation(LO)ESQK/ESRN,LOERDBESQK/ESRNThe VPC uses the LO to obtain the ESZ-related routing information from the ERDB (including the, ESRN, ESN, and CRN) that will enable the routing via the ESGW to the SR that serves this ESZ.The VPC uses the received routing information to allocate an available ESQK from the pool of ESQKs appropriate for the SR/ESN associated with the caller’s location/ESZ and sends a response to the routing request for this call, including the allocated ESQK and ESRN, as well as the appropriate LRO.
12Step 7 – Invite (ESRN, ESQK) CallserverESGWESQK/ESRNV4 interfaceThe Call Server will take the ESRN received in the response and use it as the basis for selecting the appropriate ESGW with which to route the emergency call.The Call Server routes the call to the ESGW, including the ESRN provided by the VPC and the ESQK.
13Step 8 - Call RouteESGWE9-1-1 Selective RouterESQKCAMA/ SS7The ESGW uses the received ESRN to select an outgoing route (i.e., trunk group) to the appropriate E9‑1‑1 SR.The ESGW signals an emergency call origination to the E9‑1‑1 SR, using outgoing (SS7 or MF) signaling that includes the digits “9-1-1” as the called number and the ESQK as the calling number/ANI.
14Step 9 – Deliver CallE9-1-1 S/RPSAPESQKESQKSRDBESNThe SR receives the emergency call, uses the ESQK to query the SRDB for the associated Emergency Service Number (ESN), and uses the ESN to identify the appropriate PSAP for the call.The SR then delivers the call to the appropriate PSAP, signaling the ESQK as the Automatic Number Identification (ANI) information.
15Step 10 – ALI QueryPSAPALIDatabaseESQKThe PSAP ANI/ALI controller receives the call setup signaling, and sends an ALI query to its serving ALI DB, using the ESQK as the query key.
16Step 11 - ESPOSREQVPCALIDatabaseESPOSREQw/ESQKThe ALI DB sends an Emergency Services Positioning Request (ESPOSREQ) to the VPC (identified in the shell record for the ESQK in the ALI DB), which includes the ESQK as the query key in the request.For further information on ESPOSREQ, click on the acronym
17ESPOSREQEmergency Service Position Request from ALI to MPC, is used to request the initial, updated, or last known position of a wireless handset or other device.If the requesting entity is authorized, the VPC shall use the ESQK contained in the Emergency Services Routing Key parameter of the ESPOSREQ message to identify the call instance, and to look up the associated call and location-related information stored at the VPC.
18Step 12 - ALI QueryALIDatabaseVPCESPOSREQCBN, LOC, VSPThe VPC receives the ESPOSREQ from the ALI DB, and uses the ESQK to retrieve the ALI record information it stored previously (in Step 4).The VPC returns the ESPOSREQ response to the ALI DB to provide the Callback Number, the Location information, and the VSP provided information that can be supported by the V-E2 interface.
19Step 13 - ALI ResponseALIDatabaseJohn Smith xxx-xxx-xxxx1234 W. 6th AveEagle Lake, MO.Fire - xxx xxx -xxxxEMS - xxx-xxx -xxxxPolice - xxx- xxx-xxxxALI ResponseThe ALI DB receives the ESPOREQ from the VPC (it may also extract additional information from the shell record for the ESQK).The ALI DB returns an ALI response to the PSAP, following requirements in NENA
20Step 14 – ESQK De-allocation When the VPC receives an indication that a particular instance of an emergency call is being cleared, the VPC de-allocates the associated ESQK and makes itavailable for subsequent emergency calls.Note that release of the ESQK may occur as a result of an indication of call release over the V2 interface from the Call Server/Routing Proxy, or the expiration of the ESQK guard timer, whichever occurs first.
21One More Time Altogether! 9-1-1 Call FlowEmergency ServicesProvider NetworkVoIP DomainCall Server2. Call InitiationV1V47. Invite (ESRN,ESQK)ESGW8. Call route(ESQK)E9-1-1Selective Router9. Deliver Call(ESQK)PSAP6. Response(ESRN, ESQK, LRO)V23. Query(Callback LIE),VPC(ESQK)10. ALI query13. ALI response(Callback, LO)UserAgentEndpoint1. LO and/orLKV0LISSRDB11. ESPOSREQQuery12. ESPOSREQResponse (CBN, LO)5. Response (LO)V34. Query (LK)VDBERDBDBMSMSAG14. ESQK De-allocationSBC – Southwest Public SafetyFrank Abbenhaus