Re: Replacing PSTN with VoIP wise? Was Re: Phone networks struggle in Hurricane Katrina's wake

[Michael.Dillon () btradianz com]

> I've had several reports that cell phone users who can't make *or* 
> receive calls are successfully sending *and* receiving SMS.  It could be 

> that the problem is one of not enough cell channels and working phone 
> circuits for all the phone calls people want to make, but that the SMS 
> channel is not overloaded and thus SMS traffic can zip on thru (when the 

> cell has power and can reach a working cell tower).

This was my personal experience during the July 7th terrorist
attacks in London. I couldn't make or receive voice calls
but SMS did get through both incoming and outgoing. However
the delivery of SMS messages was sometimes delayed by as
much as an hour.

SMS takes far less network bandwidth than voice calls. 
Originally it was implemented as part of the control
network of GSM (rather like SS7) but I believe that most
carriers now simply use IP networks to carry their SMS
traffic.

By now it has become clear that the response to the
New Orleans disaster has been completely screwed up
because of lack of reliable communications in and out
of the city. There are tons of food, water, medical 
supplies and personnel hung up on edge of the city
because no-one seems to know what is needed, where
it is needed, how to get it there, etc.

--Michael Dillon