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Ancient pager tech SMS: It works, it's fab, but wow, get a load of that incoming SPAM

Networks' main issue: they don't know how it works, says expert

Spam

The infrastructure for text messaging is creaking. Not only does it need to be fixed, but it seems mobile operators don’t understand enough about their own systems to do it themselves.

This is according to Louise O'Sullivan, CEO of mobile solutions firm Anam Technologies. She maintains that the problem that needs fixing lies in the history of text messaging.

The SS7 channel used by text messaging was not initially envisaged as a system for users to send messages. It wasn’t even expected to be used to connect between networks.

So when the GSM standards committee ETSI SMG4 came up with the idea of peer-to-peer messages, it was a bit of a bolt-on. According to Kevin Holley, chair of the committee and the man widely credited with being the father of SMS (something he demurs), he only expected SMS to steal a chunk of the pager market, at best.

While mobile networks were built with a network element called a short message service centre (SMSC) to control sending messages, the incoming signals were left relatively unfettered. An SMS comes into the network over dedicated lines or IP, asks the home location register where to find the phone and thus gets delivered to the recipient. All this pretty much by-passes the receiving network’s billing systems, explains O'Sullivan.

Initially the networks allowed interworking by gentlemen’s agreement and an understanding that it was in everyone’s best interest to just accept and deliver messages.

You do, of course, get billed when you send a message. And if everyone plays nicely, the delivering network can get a share of the revenue, but because of the historic architecture a huge number of networks around the world just allow messages in on the assumption that they're OK.

One inept form of defence is the IR-21 database. This lists all the numbers from which the operators should take incoming messages with a sanity check against what those operators are charging. The system doesn’t work, however, as pukka mobile phone networks (which are full GSMA members and have spectrum licences) will often rent out blocks of numbers which unscrupulous spammers can then use, sending the messages through their own or non-operators' SMSCs.

Anam Technologies claims to provide an analysis of what data is coming into a mobile phone network on the signalling channel. This looks at the source of the message, which aggregator is the source of the text message, what they are using an SMSC and ultimately giving the mobile network enough information to decide if the message should be let through. The choice to do so, is of course, that of the network.

Counter to the fashionable view that SMS is old technology, O'Sullivan claims that the need for the kind of protection her company offers is growing through the rise in machine-generated text messages.

But perhaps her biggest challenge is explaining to mobile phone networks that they don’t appear to understand what is going on inside their systems. At first blush it seems impossible that a message should arrive at a mobile phone network, travel through and be delivered to a customer’s phone without the network knowing about it. The first step is admitting they have a problem. ®

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