[Sipping-emergency] Re: Report on sipemergency call

> This is great information. Just to be sure I understand, Intrado is 
> doing two separate translations? One for a translation of the civil 
> address to lat/long, done at the time of provisioning of the civil 
> address, and the other is the translation of the lat/long into a PSAP 
> identity, done at call setup time? Its not clear to me why both 
> translations cannot be done at the same time, at provisioning time.

They probably could, but the geocoding (civil-to-geo) is presumably much 
more stable than the assignment of areas to PSAPs, except maybe after 
California drifts off into the Pacific.

> 
> Is there a site which maintains a list of providers similar to Intrado?

Not that I know of. http://www.nena9-1-1.org/Buyers%20Guide/index.htm is 
the closest I know of, but it doesn't seem to have that category. See 
also http://www.nena9-1-1.org/PSAPs/index.htm

> 
> Thanks,
> Jonathan R.
> 
> Henning Schulzrinne wrote:
> 
>> Dean, thanks for the summary.
>>
>> As it happened, I had a breakfast conversation with Vonage an hour 
>> after the call, discussing their "911" implementation. They are not 
>> calling it that, since it's only an approximation, not the real thing.
>>
>>  From my discussion, their implementation works as follows, 
>> implementing one of the stop-gap implementations that I described 
>> during the talk:
>>
>> - Customer can enter their location (street address) into a web form.
>>
>> - Customer gets reminder email once a month, as in "are you still 
>> living there"? Also, the system detects whether the subnet address of 
>> the phone has changed, indicating a likely change in physical address 
>> rather than just a new DHCP lease.
>>
>> - Address gets geo-coded (via a database maintained by Intrado, but 
>> other companies offer similar services) into longitude/latitude.
>>
>> - The outbound proxy directs all SIP requests with 911 to a special 
>> custom-coded proxy that queries (using an Intrado-proprietary 
>> XML-over-HTTP protocol) the Intrado jurisdictional database. This 
>> query returns a 10-digit number of the PSAP handling that part of the 
>> country. The Vonage fellow confirmed my suspicion that this number is 
>> often an administrative number, but at least it's the right PSAP. The 
>> call is then handed to a gateway that dials that number.
>>
>> - This approach has known limitations:
>> . requires an agreement with Intrado (they are set up to serve ILECs 
>> and CLECs, not necessarily a dynamicsoft-sized business).
>> . the calling party number is either the gateway or the caller, 
>> neither of which is likely to be mappable to anything approaching a 
>> useful street address.
>> . the manual address entry is probably only workable with mobility 
>> measured in months, not "employee takes phone home after work" or 
>> "person has multiple devices located in different places" cases. The 
>> latter case may be solvable, but things start to get a bit more 
>> complicated from a user perspective.
>>
>> Apparently, Intrado is pretty much the only vendor with nationwide 
>> coverage. Other, smaller vendors cover parts of the country.
>>
>> They are starting to roll this out in the next month or so. This is a 
>> first step, offering "basic" rather than "enhanced" 911 service.
>>
>> On average, each US household places about 1 911 call per year, so the 
>> call volume is pretty modest, from a scaling perspective.
>>
>> I mentioned the on-going IETF efforts. The Vonage fellow was very 
>> interested in contributing to the discussion. I told him that I would 
>> mention this to the group.
>>
>> Henning

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