[LINK] SMS - shortcomings in emergency services

[Kim Holburn]

I was led to believe although I never read any of them myself that the  
SLAs for SMS specify that the message does not have to be delivered  
for one or more days after it was sent.

I know people who use SMS for emergency notification in parallel with  
other methods but that is not the same as large scale emergency use.

I have a friend in South Australia who has proposed an interesting out- 
of-band solution for emergency messaging on mobile phones that has a  
number of advantages over any SMS solution.  It uses specific towers  
and broadcasts messages in a small area.  It doesn't suffer from the  
problem of scale because it uses a broadcast out-of-band channel which  
is pretty immediate (and is currently used) and because it is limited  
to one or more towers involved in the emergency.  I believe the idea  
is being examined by phone companies at the moment.  It seems to me  
that they are proposing something similar.





On 2008/Sep/19, at 12:04 AM, Richard Chirgwin wrote:

> Linkers,
>
> 3G Americas has produced this white paper (PDF, you can skip the
> registration), which provides the first serious, engineering-based
> analysis I've seen so far:
> <http://www.3gamericas.org//registration/register.cfm?content_id=118&goto=http://3gamericas.org/PDFs/Characterizing_the_Limitations_of_3rd_Party_EAS-Traynor_Sept08.pdf&newwin=0 
> >
>
> The conclusion, that SMS is unsuited to emergency notification,  
> doesn't
> surprise me. However, the detail of the analysis makes it well worth
> reading.
>
> In particular, the author notes that cellular networks are scaled for
> high utilisation (so that they're profitable). That means a "peak  
> load"
> (same message to thousands of phones) is certain to swamp the network.
> This, in turn, results in non-delivery of messages.
>
> Also, the paper observes that it's nearly impossible for users to
> authenticate an emergency notification - which means fake  
> notifications
> could be a significant problem.
>
> Finally, the message surge would block voice calls - preventing (for
> example) access to emergency service calls for any user within the
> affected cell/cells:
>
>>     Note that after the initial surge of emergency messages, nearly
>> all messages
>> and phone call requests cannot be delivered. In particular over 70%  
>> of all
>> messages and phone calls are blocked. This value does not consider  
>> the
>> impact of
>> retransmission attempts by the SMSC for the text messages that were
>> dropped
>> during the initial surge. This result is also conservative in that it
>> does not assume a
>> continued increase of calls and text messages.
>
> Richard Chirgwin
> _______________________________________________
> Link mailing list
> Link at mailman.anu.edu.au
> http://mailman.anu.edu.au/mailman/listinfo/link

--
Kim Holburn
IT Network & Security Consultant
Ph: +39 06 855 4294  M: +39 3494957443
mailto:kim at holburn.net  aim://kimholburn
skype://kholburn - PGP Public Key on request