"If they're land lines, the NPA/NXX will be local to the CO so you won't have out-of-area numbers other than a rare corner case of a very expensive foreign exchange line."
This hasn't been a true statement since Local Number Portability. NPA/NXX is nothing more than 'where the number originally was assigned from', and that only for the ones issued BEFORE LNP started; since is anyone's guess. They follow something similiar to what a routed phone call does, but ties into slightly different information that is 'supposed' to associate the end-client address with said LNI that is 'supposed' to be populated with accurate street address information. Similar to what VoIP has had to deal with since, most charge a fee, disclaim any responsibility as to the accuracy of the information that the end user provides. I am sure litigation on/around THAT particular issue is just around the corner. Regards, Jonathan Smith On Wed, Apr 13, 2016 at 11:22 PM, Jay Hennigan <j...@west.net> wrote: > On 4/13/16 8:54 PM, Peter Beckman wrote: > >> On Wed, 13 Apr 2016, Jay Hennigan wrote: >> > > When either of those people dial 9-1-1, where does the ambulance show up? >>> >> >> I suspect your response was sarcastic, but when you dig into what really >> happens, it's not nearly as sophisticated as one might hope. >> >> If the numbers are land or VoIP lines, and the address associated with >> the >> numbers are registered with the Automatic Location Information (ALI) >> database run by ILECs or 3rd parties to fetch the address keyed on the >> calling number, and the 911 PSAP is E911 capable, they operator will see >> the ALI address. >> > > If they're land lines, the NPA/NXX will be local to the CO so you won't > have out-of-area numbers other than a rare corner case of a very expensive > foreign exchange line. If they're VoIP lines, the address is *supposed* to > be so registered, but softphones and even VoIP handsets tend to move around > without the user considering 9-1-1. > > VoIP was the scenario to which I was referring. A VoIP phone native to > 408-land that moves with a remote office worker to Boston without a > conscious effort on his company and VoIP provider to track it down and > update ALI will reach a PSAP in San Jose or thereabouts. The PSAPs have > forwarding capability but generally only to neighboring PSAPs with a single > button. How quickly will they be able to get the call routed to Boston, if > at all? And as we saw at the beginning of the thread, forget geo-IP. The > ambulance goes to the Vogelmans' farm. If a remote office worker, it could > be VPN back to the VoIP PBX in 408-land anyway. > > So, it isn't just IP addresses that aren't easily geo-referenced. It's > also phone numbers. The number may start as a well-referenced PRI going to > an IP-PBX after which all bets are off. If the ANI is the company's HQ main > number where the PRI and IP-PBX are located, then it's just about > impossible to route 9-1-1 from a worker's IP phone in Boston to the right > PSAP. > > If they are mobile devices, it depends. Basic gives you nothing (all >> phones >> since 2003 should have GPS, but people hang on to phones a long time..); >> > > Mobile is a separate case where it's expected that the NPA-NXX isn't going > to be tied to a location. In California, mobile 9-1-1 goes to the CHP and > not the local PSAP based on the cell tower or GPS for that reason. If not a > traffic incident, they forward to the appropriate PSAP based on the > caller's info or perhaps whatever ALI (or estimate) they get from the > cellular provider. > > > -- > Jay Hennigan - CCIE #7880 - Network Engineering - j...@impulse.net > Impulse Internet Service - http://www.impulse.net/ > Your local telephone and internet company - 805 884-6323 - WB6RDV >
