How relable does the Internet need to be? (Was: Re: Converged Network Threat)

Jeff Shultz jeffshultz at wvi.com
Fri Feb 27 19:49:52 UTC 2004


** Reply to message from Petri Helenius <pete at he.iki.fi> on Fri, 27 Feb
2004 21:19:48 +0200

> Valdis.Kletnieks at vt.edu wrote:
> 
> >20 years ago, 911 was able to say "unless you're the rare beast with a cell
> >phone, basing it on the physical service address that the copper runs to would
> >probably work alright in 99% of the cases".
> >
> >Let's not make the same mistake again.
> >
> >  
> >
> So all IP phones should be outside of buildings and equipped with GPS or 
> Galileo receivers?
> 
> Pete

Does anyone actually offer a mobile IP phone service yet? Does anyone
plan to? 

With Vonage you have to tell them where you are located so they can set
your 911 service up to the proper 911 center.  

With cell phones it's based on the cell it comes into. If some sort of
truly mobile IP based phone comes in, I'd guess that the provider is
going to have to set it up to where the local router (or associated
VOIP device) "listens" to the VOIP traffic for a 911 call, intercepts
it and sends it to the local 911 center - my presumption is that
they'll have to have a router of some sort in the local area to handle
the mobile IP traffic.  The GPS idea isn't a bad one either - since I
think most new cell phones are coming out with this (it's been
mandated, right?) it's a cheap addition and can be used by whatever the
router redirects the call to for a better determination of the call
center if the phone has the info. 

The easier solution would probably be for the "mobile IP phone service"
to set it up as a dynamic address thing, where the phone number is
assigned to the MAC address and the system updates a central index of
what IP address is currently serving what phone number. And by whatever
"DHCP" server assigned the address, that would be used to determine the
911 center most appropriate. 

As for the varied emergency numbers used throughout the world and
such... if you are visiting a foreign country, take the time to figure
out what the local (national) emergency numbers are.  Much easier than
an overly complex technological solution. Or add an "emergency" button
on the phone that will send a signal that the switch will read as
whatever the national emergency number is. 

Experience here: last summer I was at Ft. Campbell, KY, and a friend
and I drove on the local interstate down to Nashville - when you get on
the Interstate there you are in Tennesse, then you are in Kentucky for
a short period (a few miles) and then back to Tennesse. I had to call
911on my cell for an accident and was connectted to a 911 center in
Tennesee... but since I was on the Kentucky stretch of freeway they had
to transfer me over to the local Kentucky 911 center.  No problem. I
suspect that as long as the VOIP 911 thing can get you "close" to the
correct 911 center, they'll be able to handle the rest of the switching
needed. And realistically - that's probably a better solution than
trying to come up with an overly complex technological solution. 

These are supposed to be phones after all, not "dumb" ELT devices.

Let the OT rants begin....

-- 
Jeff Shultz
Loose nut behind the wheel. 




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