A new report published by U.S. trade group, 3G America's, notes that the use of SMS as an emergency alert service poses serious limitations.
The report, Characterizing the Limitations of Third-Party EAS Over Cellular Text Messaging Services (PDF), notes that while use of text messaging or SMS has become ubiquitous and commonplace for recreational and business purposes, the research indicates that there are serious limitations of third party Emergency Alert Systems (EAS).
Author Patrick Traynor says, ”SMS is touted as being able to deliver critical information during disaster events, and such services have been purchased by universities and municipalities hoping to protect the general public.” Unfortunately, such systems typically will not work as advertised.”
Traynor cites a number of reasons why emergency alerts over SMS in current cellular systems are simply not feasible or recommended: cellular networks are not designed to delivery emergency-scale traffic loads; targeting users in a specific location is extremely difficult; there is no way to authenticate the source of messages, making fraudulent alerts easy to send; SMS is not a real-time service; and message delivery order is not always predictable.
Traynor notes that even under optimal conditions, networks cannot meet the ten minute alert goal generally set forth by public emergency alert charters. Moreover, the extra text messaging traffic generated by third party emergency alert systems causes congestion in the network and may potentially block the delivery of critical information such as calls between emergency responders or the public to 9-1-1 services. The report concludes that it is critical that legislators, technologists and the general public understand the current limitations of these systems.
Simulating emergency communications in a series of tests, Traynor notes that there is a "mismatch between the current cellular infrastructure and EAS...Accordingly, such systems can not currently form the basis of a reliable alert system in the timescales required by the WARN Act, regardless of promises made by third party systems. However, the ubiquity of cellular phones gives them a potential role in the delivery of critical information during an
emergency. This role would be complementary to the other platforms of the
Emergency Broadcasting System (television, radio, etc.)."
Solutions such as the efforts undertaken by the Commercial Mobile Service Alert Advisory Committee (CMSAAC) set up by the United States Federal Communications Commission will allow cellular networks to take an active role during emergencies. The report suggests that through the creation of new standards such as Cell Broadcast many of the problems created by the current ”point to point” architecture can be avoided. In particular, by allowing each base station to act as a virtual megaphone, cellular networks are better able to rapidly distribute up to the moment emergency messages to all phones.
Traynor, the author of the report, is an Assistant Professor in the School of Computer Science at the Georgia Institute of Technology, and an expert in security for cellular networks.
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