1. NENA’s 11 th Annual Technical Development Conference A proposal to support E911 calls on Voice over IP Networks Martin Dawson – Nortel Networks

2. Slide 1 The existing emergency network interfaces Selective Router ALI Local National Wireline LEC Cellular PAM ISUP E2+ ESP CAMA Emergency Services N/W Voice N/Ws

3. Slide 2 E911 – Key functions of location information The idea of the subscriber’s location is important to E911 call handling in two key aspects: ROUTING ROUTING The dialed digits, 911, do not contain any explicit routing information. The dialed digits, 911, do not contain any explicit routing information. The call needs to be delivered to the Public Safety Answering Point specific to the jurisdiction from which the call is originating. The call needs to be delivered to the Public Safety Answering Point specific to the jurisdiction from which the call is originating. This is necessary to facilitate notification of the correct local emergency response unit. This is necessary to facilitate notification of the correct local emergency response unit. LOCATION DELIVERY & DISPLAY LOCATION DELIVERY & DISPLAY Ideally a PSAP operator can obtain a display of the location of a caller in conjunction with the call itself. Ideally a PSAP operator can obtain a display of the location of a caller in conjunction with the call itself. Allows emergency teams to be dispatched to the destination quickly without depending on the caller to provide the location – which they may not know. Allows emergency teams to be dispatched to the destination quickly without depending on the caller to provide the location – which they may not know. Could be a “Civic Address” or “Geodetic” (lat/lon) location. Could be a “Civic Address” or “Geodetic” (lat/lon) location.

4. Slide 3 Routing – Local wireline calling Local Exchange Selective Router PSAPs Incoming local line and CLID provides an indication of the fixed location and, therefore, correct destination PSAP for the caller.

5. Slide 4 Routing – Cellular calling PSAP Zone A PSAP Zone B BSC SMLC MSC Selective Router GMLC ZDB Selective Router Location Determination Lat-Lon ESRK S/R chosen on cell ID PSAP chosen on ESRK Cellular No association between CLID and Location. Selective Router chosen based on Serving Cell location. PSAP selected based on Lat/Lon (or cell). MSC has dedicated trunks to all Selective Routers in service area. Cellular No association between CLID and Location. Selective Router chosen based on Serving Cell location. PSAP selected based on Lat/Lon (or cell). MSC has dedicated trunks to all Selective Routers in service area.

6. Slide 5 Delivering Location – Local wireline Local Exchange Selective Router PSAP The PSAP can query the ALI database with the caller’s CLID and receive a civic address in return. The CLID and street address have an explicit association. ALI PAM CAMA CLID Address

7. Slide 6 Location Delivery – Cellular PSAP BSC SMLC MSC Selective Router GMLC ESPOSREQ (ESRK+CLID) LocBid(pANI|ESRK) The ESRK generated by the positioning systems becomes a key to the call in progress. A location bid from the PSAP is converted to an ESPOSREQ to the cellular network to have the location associated with that call returned. * Phase 1 Location: Nominally the street address of the serving BTS The ESRK generated by the positioning systems becomes a key to the call in progress. A location bid from the PSAP is converted to an ESPOSREQ to the cellular network to have the location associated with that call returned. * Phase 1 Location: Nominally the street address of the serving BTS ALI PAM E2+ ESP esposreq (lat-lon + Phase1 loc*) CAMA LocResp(LocInfo)

8. Slide 7 VoIP networks have much in common with cellular networks in terms of the challenges presented by E911. VoIP networks have much in common with cellular networks in terms of the challenges presented by E911. VoIP clients can be nomadic or, even, fully mobile. VoIP clients can be nomadic or, even, fully mobile. There is no location association between a CLID nor, even, the call server providing service and the client. There is no location association between a CLID nor, even, the call server providing service and the client. How to support VoIP without impacting the emergency network? How to support VoIP without impacting the emergency network? Routing – the concept of a routing key (ESRK) can be reused. Routing – the concept of a routing key (ESRK) can be reused. Location Delivery – the E2 interface already supports queries for dynamically determined location. Location Delivery – the E2 interface already supports queries for dynamically determined location. For “fixed VoIP subscribers” a mechanism also exists for delivering civic address, if that is more appropriate than geodetic location. For “fixed VoIP subscribers” a mechanism also exists for delivering civic address, if that is more appropriate than geodetic location. Voice over IP (VoIP) – Special challenges Call Server

9. Slide 8 Goal - adding a new voice network Without impacting existing emergency network interfaces Selective Router ALI Local National PAM CAMA Cellular Emergency Services N/W Voice N/Ws Wireline LEC VoIP ISUP E2+ ESP

10. Slide 9 ROUTING Reusing the ESRK for VoIP Selective Router ALI Local National PAM CAMA Cellular Emergency Services N/W Voice N/Ws Wireline LEC IP ISUP E2+ ESP Trunk MG Call Server S/R selected based on ESRK PSAP selected based on ESRK ECReq(ClientID) ECTerm(ESRK) LGS* * LGS – Location Gateway Server ECRsp(ESRK)

11. Slide 10 Considerations for Routing In both local wireline and cellular, the switching entities have dedicated trunks to the Selective Routers For carrier VoIP networks For carrier VoIP networks There is a similar assumption that every subscriber service area will include Point of Presence (PoP) with a Trunk Media Gateway. There is a similar assumption that every subscriber service area will include Point of Presence (PoP) with a Trunk Media Gateway. The Trunk Media Gateway supports the dedicated S/R trunks. The Trunk Media Gateway supports the dedicated S/R trunks. Carriers may elect to share the PoP resources for emergency services Carriers may elect to share the PoP resources for emergency services In the absence of a PoP and for enterprise VoIP In the absence of a PoP and for enterprise VoIP Direct dial numbers for PSAPs may be used in place of the ESRK. Direct dial numbers for PSAPs may be used in place of the ESRK. Routing is performed based on the direct dial number in the Called Party Number of the ISUP signaling. Routing is performed based on the direct dial number in the Called Party Number of the ISUP signaling. The LGS provides the direct dial number in addition to the ESRK. The LGS provides the direct dial number in addition to the ESRK. Such an approach may not be scalable for PSAPs, may be less reliable (call tandemed through the PSTN), and may not allow enhanced 911 service. But it is a viable fallback. Such an approach may not be scalable for PSAPs, may be less reliable (call tandemed through the PSTN), and may not allow enhanced 911 service. But it is a viable fallback.

12. Slide 11 LOCATION DELIVERY Reusing the E2 Interface for VoIP Selective Router ALI Local National PAM CAMA Cellular Emergency Services N/W Voice N/Ws Wireline LEC IP ISUP Trunk MG LGS Call Server E2+ ESP ESPOSREQ(ESRK) esposreq(Location)

13. Slide 12 Determining Location The LIS – access specific location determination Selective Router ALI Local National PAM CAMA Cellular Emergency Services N/W Voice N/Ws Wireline LEC IP ISUP E2+ ESP Trunk MG LGS Call Server PLR(Location) LIS* * LIS – Location Identification Server ECReq(ClientID) ECRsp(ESRK) PLR(ClientID) Access specific positioning methods

14. Slide 13 Geodetic Location vs Civic Address The E2 interface allows a “Location Description” to be provided in addition to the geodetic location: Geodetic Location Geodetic Location Required for clients which are arbitrarily mobile, where a specific address is not applicable or relevant Required for clients which are arbitrarily mobile, where a specific address is not applicable or relevant Coded in WGS-84 coordinate system. Effectively the latitude and longitude of the client – plus an uncertainty radius* Coded in WGS-84 coordinate system. Effectively the latitude and longitude of the client – plus an uncertainty radius* Can be determined dynamically by the LIS using appropriate technology (Port wire map, WiFi triangulation, GPS) Can be determined dynamically by the LIS using appropriate technology (Port wire map, WiFi triangulation, GPS) Delivered in Position Information parameter of esposreq* Delivered in Position Information parameter of esposreq* Civic Address Civic Address May be more relevant for fixed/wired clients (e.g. desktop phone form factor devices) May be more relevant for fixed/wired clients (e.g. desktop phone form factor devices) Provides a conventional street address* Provides a conventional street address* Can be determined by LIS against static port (switch, DSLAM, etc.) datafill Can be determined by LIS against static port (switch, DSLAM, etc.) datafill Delivered in ESP “Location Description” parameter of esposreq* Delivered in ESP “Location Description” parameter of esposreq* * See NENA Standard for the Implementation of the Wireless Emergency Service Protocol E2 Interface.

15. Slide 14 Using DHCP to support a distributed implementation with roaming Selective Router DHCP LIS Call Server eLGS ZDB Trunk MG LIS-ID eLGS-ID Emergency Call Init (eLGS-ID, LIS-ID) ECReq (LIS-ID) CAMA ISUP Home Network Visited Network Access Network Emergency Network 1 2 3 The visited network may be: Another carrier for a roaming subscriber The local VoIP carrier for an enterprise network Permits enterprise to use direct trunking instead of direct dial routing. The visited network may be: Another carrier for a roaming subscriber The local VoIP carrier for an enterprise network Permits enterprise to use direct trunking instead of direct dial routing.

16. Slide 15 What does this proposal need: VoIP Standards – short term VoIP Standards – short term Call Server to LGS messaging Call Server to LGS messaging EC Request/Response/Terminate. EC Request/Response/Terminate. SIP based? SIP based? LGS to LIS messaging LGS to LIS messaging Perform Location Request/Response Perform Location Request/Response SIP based? SIP based? E2+ - New code points for IP position source, Use of Locn Description for Civic Address E2+ - New code points for IP position source, Use of Locn Description for Civic Address Location determination - short term Location determination - short term LIS implementations which can work with LIS implementations which can work with Legacy client devices Legacy client devices Legacy access networks Legacy access networks VoIP Standards – longer term VoIP Standards – longer term Enhanced LIS messaging (e.g. LIS-Client for A-GPS requests) Enhanced LIS messaging (e.g. LIS-Client for A-GPS requests) Enhanced Client to Call Server messaging Enhanced Client to Call Server messaging Immediate location delivery to call server Immediate location delivery to call server LIS-ID and emergency LGS-ID delivery LIS-ID and emergency LGS-ID delivery DHCP support DHCP support Delivery of local LIS and LGS identities to client on initialisation Delivery of local LIS and LGS identities to client on initialisation Location determination – longer term Location determination – longer term Advanced positioning for IP clients – WiFi triangulation, Assisted GPS Advanced positioning for IP clients – WiFi triangulation, Assisted GPS Mid-call position updates for fully mobile clients (already supported on E2) Mid-call position updates for fully mobile clients (already supported on E2) The E911 support imperative is very pressing. The question is how to best, and most quickly, get a solution in place.

17. Contact details: Martin Dawson Nortel Networks mdawson@nortelnetworks.com Contact details: Martin Dawson Nortel Networks mdawson@nortelnetworks.com Thankyou