The Pros (and Cons) of Multi-network SIMs.

We’ve all seen the ‘Big 4’ (EE, Vodafone, O2, Three) say they’ve got the best, or the fastest, or the broadest, coverage around, but marketing isn’t always truthful…

Plus, in real-world settings, especially in business environments where absolute reliability is so important, businesses often rely on Multi-network SIMs to ensure systems have the best possible connection, no matter the area, weather or anything else for that matter.

In principle, Multi-network (or Roaming SIMs) provide the best access to all 2G, 3G and 4G networks in any one place, which sounds like a great solution, compared to relying on only one network.

However, not all Multi-network systems are created equal…

Some SIMs have a preference

These are known as ‘Steered’ (as opposed to ‘Unsteered’ SIMs), where Steered SIMs will always prefer a specific network over the rest, only switching to another if their primary preference isn’t working.

Most of the time, steering is used to reduce costs, preferring the cheapest network to keep costs low – Whether those savings are passed on to you, the end customer, is another bag of worms too!

This great for areas where signal is strong across multiple networks, but is generally the opposite of what’s wanted by customers, as it puts cost above reliability, when the whole point is to be as close to 100% network uptime as possible!

On the other hand, an Unsteered SIM is a neutral, blank canvas that simply provides access to networks as and when required with no ‘loading of the dice’. This is arguably the most preferable starting point for any M2M/IoT application where uptime and reliability are key.

But this is only part of the battle…

Automatic network switching can be misleading too

Contrary to what you may assume from what we’ve said above, how SIMs select the network isn’t always determined via the SIM card itself.

Instead, it’s usually a function of the hardware the SIM card is plugged into, when it realises there’s an issue with the current network it’s connected to, not the card itself.

This means it’s possible to use a Multi-network SIM, but still find that the router/modem doesn’t switch to an alternative network when connectivity is lost.

“This issue isn’t spoken about enough, and has big implications for those expecting everything to ‘just work’, when Roaming SIMs are used with automatic network selection hardware.” Richard Foleher, Technical Director, Everything Voice

The process doesn’t always factor in whether the connection is live, and just takes the signal strength as an indicator of which network to pick.

So, when the hardware sees good signal strength but cannot communicate with a server on the internet, it will continue to look ‘connected’ completely oblivious to the fact no data is going back or forth!  

Everything Voice customers never get these problems, thanks to some fancy firmware!

All the Multi-network solutions we deliver solve these challenges by supplementing Automatic network selection with ‘periodic Health-checks’ and the option for ‘Manual network selection’ to make sure reliability is as high as it possibly can.

Our intelligent routers can be configured to check for loss of mobile data communications every so often (called Roaming Checks), forcing the SIM to change networks within regular intervals if need be.

This can save the cost of site visits and provides peace of mind that you have implemented the ‘highest reliability’ methodology for your connected devices before rolling out a large estate of cellular-connected devices.

Our Roaming Checks look not only at signal strength, but also ‘Ping times’ and ‘Ping completion’, to build a more complete picture of the current connection. Ping times are a great indicator of how quick the connection is, with a lower Ping meaning a better, faster, stronger connection. Ping completion is a great indicator of reliability too.

If the Health-check is failed, or Ping-times pass a threshold you can define, the router will dynamically assess the quality of alternative networks and change to the next best if communications are lost or are of a ‘low quality’.

In summary, if you want a super-reliable mobile network – whether for on-site calls, IoT, CCTV, sensors or anything else, we can make sure you’re not blinded by marketing speak, sneaky SIMs or networks that don’t realise when they’re not connected!