1. North American Emergency Services Brian Rosen Emergicom

2. 9-1-1 Calls Single universal number for all networks throughout North America (wireline, wireless, …) Answered at one of ~6,134 Public Safety Answering Points Dispatched to tens of thousands of police/fire/emergency medical agencies A function of LOCAL government, not significantly controlled by state/federal governments – Often City or County – But often there are multiple PSAPs per county – Please don’t ask us to fix this, it’s been tried

3. PSAP Boundaries Every PSAP has a service area All calls from within that boundary must go to that PSAP PSAP boundaries do not necessarily lie on neat (e.g. City, County) boundaries The DEFINITION of a PSAP boundary is currently done on a street/number basis, which has been manually translated into a point/polygon form also Dealing with non-trivial boundaries is the big problem in routing calls

4. Wireline Calls SUBSCRIBER E911 TANDEM OFFICE END OFFICE ANI PSAP ATTENDENT POSITIONS COMMON EQUIPMENT SRDB ALI HOST 1 2 3 4 5 5 6 7 7

5. ERDB & ALI DB Translates phone number to location & routing data Maintained by a designated service provider Carriers process service orders into ALI (and SR DB) for new/changed customers Location (to be associated with phone number) is VALIDATED against the Master Street Address Guide prior to entry in the ALI

6. MSAG Validation Database for locations Lists every address (actually an address range) in the area served by the local 9-1-1 system Maintained by the local 9-1-1 authority. Normally one MSAG per local authority (which often covers more than one PSAP), but there are exceptions Contains the ESN (code for ESZ) Indirectly specifies the PSAP to which the call is sent Implies the S/R (MSAG coverage doesn’t normally cross S/R service areas, but they do sometimes).

7. Wireless (Phase II) Calls MSC PDEMPC ESNE (Selective Router) ESME (ALI Database) CRDBPSAP E5E5 E 12 E3E3 E 11 E2E2 AiAi DiDi Cellsite (ESP) (ISUP) (ANSI-41) (LSP) (ANSI-41) CRDBCoordinate Routing Database PDEPosition Determining Entity MSCMobile Switching Center MPCMobile Position Center CAMA

8. NENA “i2”

9. So, what’s the problem? Translate LO (in civic or geo form) to PSAP URI The boundaries are in the MSAGs, and are not simple; a real database is required – You can do the database lookup before you need it, but boundaries change all the time We need room level location (although boundaries don’t cross rooms) We need validation of a (civic) location PRIOR to use There is more data that just the PSAP URI associated with the location (e.g. Responder ids/uris)