[VOIPSEC] VOIP for free??

[Robert Moskowitz]

At 07:48 PM 4/9/2005, Brian Rosen wrote:
>Unfortunately, there are two problems with gps  phones. The first is that 
>it doesn't work indoors.  There are folks working on that, but don't plan 
>on solutions real soon.  The other problem is that its not accurate enough 
>unless you use some kind of assisted gps.  In the u.s., the WAAS system 
>will probably work in a lot of places.  Mobile carriers who use gps 
>provide assisted gps to get the required accuracy.

Of course, this is a bit afield as GPS is just a service that may benefit 
Voip,or not as you indicated.

The reachablity challenge of GPS is actually part of my point.  It is the 
device you want to authenticate and its location.  AN IP address is NOT a 
location.  It is a routing vector.  Vint and I had lots of discussion about 
this in the Namespace IRTF.

Yes, I was following the DNS location work.  It is good for maybe 90% of 
the cases.  As Brian points out we need 100%.  If .01% of callers cannot 
give their location, and DNS location works 90% of the time, that means 
that 1 in 1000 callers will be mislocated.  Not good numbers.  I suspect 
the numbers might be a bit brigher than that, but it still reminds me about 
the story of Windows reliablity compared to airplanes.

As to the accuracy of GPS, we had location averaging of bad data before the 
bad data varriable was removed.  Some of the systems I saw were really good 
at getting the true location that way.  My contacts over at NRL were even 
laughing that some of the averaging software was getting better location 
than the standard software used by the navy.  Of course, this means you are 
stationary for a while....

We need to just list device location as a requirement for relaiable 
E911.  Then we can develop best practices along with appropriate disclaimers.

And Brian, I am very interested to know what body is working on this 
location standardization work you mentioned.



Robert Moskowitz
Senior Technical Director
ICSA Labs, a division of Cybertrust, Inc.
W:      248-968-9809
F:      248-968-2824
E:      rgm at icsalabs.com

There's no limit to what can be accomplished
if it doesn't matter who gets the credit