Recently Optus began filtering its SMS traffic on its network – what does that mean? What it means is that if the messages are not coming through a preapproved route, i.e. directly through Optus or a network that connects to Optus, then it’s likely that the message will not be delivered.Why have Optus done it? The answer is twofold, firstly, it helps protect Optus’ customers from receiving an abundance of spam SMS from off shore services, so there may be a few less winners of the euro mobile lottery! Secondly, it’s about revenue leakage – over the past number of years the networks have seen a plateauing of revenue coming from Premium Rate SMS, but an increase in revenue coming from non-Premium Rate SMS, or as we call it Business SMS.Every time a network receives an SMS from another SMS network it charges an interconnect rate for delivering said SMS. Network filtering ensures all messages accepted and delivered to the handset come through the correct channel – when it doesn’t, it’s called grey routing. Now grey routing routes the messages in various ways designed specifically to avoid any interconnect charges, the analogy is like me asking you to mow my lawn, but not paying for it.So what’s happening? Well, a few companies using grey routes have already increased their prices, but for the most part, to be honest not a lot, and one of the reason for that is because Optus are sending through successfully delivery receipts on blocked messages – yes, that’s right, Optus aren’t telling routes which messages have been blocked and which messages haven’t been blocked, so as a matter of course Esendex are recommending to everyone to test the services they’re using in two ways; send a message to an Optus handset with a numerical originator (basically send a message coming from a mobile number) and then send another test message from an alpha numerical originator (i.e. your business name) to see whether they’re going through.Whilst Optus have had the filtering on the in the background collecting the data on which routes to block, we’re still not expecting to see the full blocking for a couple of months, so it would be good practice to keep sending test SMS to your Optus handsets over the course of the next 2-3 months to ensure your messages are in fact getting delivered.And what’s the next step? Well, the next step will be Vodafone (VHA) investigating filtering – although at ~24% market share at the moment, they are the last of the providers to implement filtering in Australia, which will see a total clean-up of the market, although for some, it means messaging costs will jump up significantly, overall it will be much better for the market and a clean-up of spam messaging, which let’s face it, no one wants to receive.