Emergency Services (E911)

We need to support 3 things according to Henning Schulzrinne [Schulzrinne 2000]:

There must exist an emergency address (similar to 911, 112, help, …)
find Public Safety Answering Point (PSAP)
- outbound proxy -- only if there is a well bounded geographic area served by this proxy
- use DNS where the user or device enters a relevant name: e.g., pittsburgh.pa.911.arpa
- SLP - but scope not likely to coincide with ESR
- call volume:
  - Sweden: SOSAlarm.se has 20 call centers distributed around Sweden with ~18 million calls/year with ~20% of them calls to 112 the rest are automatic alarms;
  - US: National Emergency Number Association (NENA) reports >500,000 calls/day or 190 million a year (more than 80% are not emergencies ⇒ 311 non-emergency number)
obtain caller’s identity and geographical address
- this is done to minimize prank calls
- caller provides in request
  - Geographic position: N 59 24.220' E017° 57.029' +/- 77m and/or
  - Geographic Location: "5th floor, Isafjordsgatan 22, Kista, Stockholm, Sweden"
- or PSAP queries caller
- or PSAP queries third party based on caller identity

note: Enhanced 911 (E911) - mandated by FCC for cellular phones in US

Slide Notes

Henning Schulzrinne, “SIP for Emergency Services”, 48th IETF (Pittsburgh), July 2000, http://www.cs.columbia.edu/sip/talks/ietf0008_911.pdf Links to an external site.

Thomson and J. Winterbottom, “Revised Civic Location Format for Presence Information Data Format Location Object (PIDF-LO)”, Internet Request for Comments, RFC Editor, RFC 5139 (Proposed Standard), ISSN 2070-1721, February 2008 http://www.rfc-editor.org/rfc/rfc5139.txt Links to an external site.

Transcript

[slide435] So, how do we give it service that's better than best effort service? Well, emergency services, or E911 in the US, the idea is that when you place a call to one of those numbers, it goes to a public safety answering point. In Sweden, there are 20 SOS alarm centers, about 18 million calls a year. About 20% of them are people who dialed 112. It means 80% of the calls are coming from what? Automatic alarms. Computers. And what do those systems do? I am alarm number 57623. I'm reporting blah blah. Yes, they generate voice, so that the human user at the alarm center takes that, listens to it, types the message in. Incredibly stupid, right? So, we have a computer talking by a voice to a human, who is then interpreting it and typing the information into another system. Why not just directly send the alarm information right into the computer system? Why not? Anyone want to guess why? No, it has nothing to do with that. Why? No, because we can even have these alarms sign the messages digitally. The biggest problem was, these systems all date to requirements that you had to have this for humans dialing the emergency number. Alarm systems came along later. And because you have these human-manned emergency centers, the obvious thing was to make it so that the call could be received by the human. The bad news is, oops, 80% of them are being made by machines. The other problem is, the SOS call centers are physically tied to the switches, so that when a call comes into that switch, it directs the emergency calls to the SOS center associated with that region of the country. Is this a good idea or a bad idea? Oops, bad idea. Why? Well, when big disasters happen, what happens? This particular call center gets saturated with phone calls, and there are 19 other call centers where it's business as usual. So what can you do? You can think about redistributing those calls to all the call centers, by just doing load distribution of them, and now you deliver it along with information about where the call was from. So, yes, it could be a disaster in Stockholm. The call center in Luleå says, no problem, it's a quiet day here, a little bit more snow than yesterday, but we'll help you with your problem. The U.S. National Emergency Number Association reported, and this is some years ago, that 500,000 calls a day, or 190 million calls, to the emergency numbers were not emergencies. So what did they do? They introduced a new non-emergency number, 3-1-1, instead of 9-1-1. So if you spotted that there was water pouring out of a fire hydrant, you could call 3-1-1 and report that, instead of calling the emergency service to unload, they could actually handle emergencies. But the difficulty is, we want to find the caller's identity and their geographic location. As was mentioned earlier, one of the reasons was to minimize prank calls, but that's not such a big problem for equipment. The other is to provide the position, but is that a geographic position, or is it a geographic location? 5th floor Isafjordsgatan 22, whatever, or 59 degrees, 24.220, north, east, 17 degrees, 57029, which I think is just above here, plus or minus 77 meters. And enhanced 9-1-1 was mandated by the U.S. regulators for cellular industries.