[e2e] 911 and cell phones

Henning Schulzrinne hgs at cs.columbia.edu
Fri Apr 1 07:11:31 PST 2005

People interested in this topic might want to follow the work of the 
ECRIT working group in the IETF (and, for location delivery, the GEOPRIV 
working group). Some related material can be found at 

Short summary: Emergency calling ("911") is undergoing a radical 
technical transformation, motivated by the difficulty to support mobile 
devices, number portability, telematics services and VoIP in the 
traditional, 1960ish technology that is currently being used. As usual, 
it will take a decade or more for this transition.

Black_David at emc.com wrote:
> David,
> It's too bad that California screwed this up.  I know from
> actual experience that calling 911 from at least my cell
> phone in Mass. enables one to reach the state police in 
> short order.
> As for "exact position" of a cell phone, I think that's a red
> herring, because the only way to get it accurately appears to
> involve a GPS receiver in the cell phone, which most cell
> phones don't have.  While I'm not an expert, my impression
> from what I've seen is that triangulation based on location
> of cell site antennas has not been sufficiently workable
> in practice.  Even GPS has its limits - if the receiver can't
> see enough satellites, the result is a 2-D fix instead
> of 3-D, which can be a problem in a multi-story building.
> OTOH, if you want to trust your life to a global SLP
> infrastructure (Uh, where can I find one of those?),
> that's your choice ...
> Thanks,
> --David
> ----------------------------------------------------
> David L. Black, Senior Technologist
> EMC Corporation, 176 South St., Hopkinton, MA  01748
> +1 (508) 293-7953             FAX: +1 (508) 293-7786
> black_david at emc.com        Mobile: +1 (978) 394-7754
> ----------------------------------------------------
>>-----Original Message-----
>>From: end2end-interest-bounces at postel.org 
>>[mailto:end2end-interest-bounces at postel.org] On Behalf Of 
>>David P. Reed
>>Sent: Thursday, March 31, 2005 1:13 PM
>>To: Alex Cannara
>>Cc: end2end-interest at postel.org
>>Subject: Re: [e2e] Skype and congestion collapse.
>>Alex - the underlying assumption is that traditional telephony delivers 
>>911 functionality best.   Well, the word on the street is that in 
>>California, if you call 911 on your basic, non IP cell phone, your exact 
>>position is delivered to ... well, no one knows where, but it's a place 
>>that has no capability to actually transfer that information to anyone 
>>who actually can help you in an emergency.   Better to call directory 
>>assistance for the phone number of your local police dept. and hope they 
>>don't tell you "911", because that will guarantee 30-90 minutes of 
>>screwing around.
>>OK, maybe wired phones still do 911 OK, but do PBXes?   I doubt it - so 
>>the point about bosses may be bogus as well.
>>Here the argument that 911 should be "in the network" fails.  I'd much 
>>rather have my actual physical telephone be smart enough to figure out 
>>how to summon emergency services (perhaps finding the doctor who is in 
>>the next cubicle over if the SLP emergency service existed), I think.
>>Dale Hatfield points out that the phone companies have made it 
>>*impossible* to deploy a "911-like" service over the WWW, because who 
>>can trust that a person would actually tell the truth that they have a 
>>life or death situation on their hands.   But of course we can ALL trust 
>>Verizon Wireless with our lives... yeah right.

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