If your SIM stops working in your phone the operator will send you a new one, next day, and you will say ‘wow the service is awesome’ or at least that’s what happens in the marketing. What is clear is that the cost of a failure is likely to be low. While you are waiting for the SIM to arrive it is likely that you will be able to borrow other phones around you to make the calls that have to be made.Now do the same with an M2M SIM in a typical example such as an Automatic Number Plate Recognition Camera (ANPR) and the impact is far greater. First of all there will be a gap while a repair team is put together; your kit could be out of action for a day or a month. Then on the day of the fix there is a lane closure, 2 trained staff and a cherry picker. £1000’s in cost and in lost service.
The bizarre truth is there is probably nothing wrong with the physical SIM. For the last eight years most reputable M2M specialist have been supplying SIMs that are ‘hardened’ This means that they are tougher than the one in your phone, can handle extremes of temperature better and are designed to be out in the field for ten years or more rather than 1 year cosily tucked in up someone’s pocket.The reasons that most of these SIMs fail is because of the interaction between the hardware and the network. Both are always changing and keeping up with the latest expectations from both sides is a speciality in itself. The other reason why they fail is because the networks have made changes to the profile of the SIM without realising the impact that would have on Machine to Machine applications. This is why Mobius is the only MVNO that performs a rolling audit on its entire estate every quarter.In the 9 years that we have been in M2M we have had a handful of SIMs that have failed, these were mainly down to extreme temperature (-40°C) or because of badly written software that was constantly writing to the on board memory.Some companies have gone back to shipping consumer SIMs to save money. We only use M2M hardened SIMs that have a high read write memory and a wider temperature spec. MBB and Voice use consumer grade SIMs.
The network can also be a source of failure. Although they quote 3 or 5 gig packages most of their maths is based around 400MB per month and they help you to stay near to that figure by applying a fair use policy, this includes, choked throughput speeds, Content Filters, Fair Usage Speed Restrictions, Involuntary Compression, over the air updates and streaming are not allowed. Peer to Peer is also not allowed, most M2M applications use P2P, your device sends a bit of information to the server every hour of everyday, that’s P2P. All of these filters increase latency, by as much as 10 times, taking a round trip of 100ms and turning it into a second! How will an M2M application deal with latency that high? A true M2M tariff does not have any of these filters.M2M tariffs are more expensive because the operators know that if you buy a 1GB tariff you are going to use 1GB, and not the 400MB that the average user consumes. So picking the right tariff is important as getting it wrong can be costly.Once you have the right tariff, how do you smooth out the locations that are busier than the others? Data aggregation, lets say you have 100 sites that all consume just under 1MB per month on average, however some sites use 2MB and others only 0.5MB. Wouldn’t it be good if you have 100 1MB SIMs that can all take out of a 100MB pool of data?
The other hidden cost occurs where Mobile operators normally round data sessions up to the nearest KB some to 10KB and a few even round to 100KB. On your mobile phone, all you can eat tariff, who cares? No one.M2M is a little more sensitive than that, here is a real life example.Islington had designed there software that monitors the location of the traffic wardens to be very slick, every 30 seconds it sent a well crafted 9 byte packet to the server to give the wardens location. However the device connected, sent 9 bytes, and then disconnected, the way that the network dealt with that was round it to a KB. This effectively increased there data consumption by a factor of 115. By moving there estate to Mobius we were able to bill them to the byte and put them on the right tariff saving them £300,000 in the first year and £1.8 million over the term of the contract.
Management of a large SIM estate is also very important when controlling cost, a good management platform will let you drill down to see data sessions and the networks view of usage, 9 bytes or 1KB in the example above.