Robustel Smart Roaming V2

Next generation 3G/4G reliability & roaming SIM management from Robustel

SMART roaming is a new technology available exclusively in Robustel routers to increase cellular (3G/4G) connection reliability to the levels required by IoT and M2M solution providers.

Multi-network (aka roaming) SIMs have often been proposed as the solution to intermittent GSM communications but this is only half the story – a story rarely understood or fully explained by those selling such products.

“Figure 1 – Speedtest view of Smart Roaming v2 menu”

The Problem

In principle, roaming SIMs that give access to all 2G, 3G and 4G networks in any one country sound like a great solution to the limitations of making a cellular internet connection through a single network operator (e.g. Vodafone).

Finite coverage and potential intermittent congestion are the key issues that can cause downtime if a single network SIM is used as opposed to a roaming one. However, using a roaming SIM is only part of the solution.

Network selection is a function of the hardware NOT the SIM card so whilst a roaming SIM seems like a good idea in principle, it is possible to use a multi-network SIM but still find that your device (router/modem) does not move to an alternative network when connectivity is lost.

The full details of the process that governs ‘network selection’ is described in 3GPP standard TS 3GPP 23.122 which can be downloaded from ‘’. This will help explain to the more technical reader the full detail and limitations of automatic network selection.

The Author’s anecdotal experience over many years is that system integrators opt for a roaming SIM and are sometimes disappointed to discover that they can still be confronted by obscure connectivity issues that are hard to understand and more importantly, hard to fix.

The Solution

All Robustel routers that support ‘Smart Roaming’ or ‘Smart Roaming v2’ can be configured to check for loss of mobile data communications on the current network and be forced to change to an alternative network within a short period of time. This can save the cost of site visits and provides peace of mind that you have implemented the ‘highest reliability’ Comms methodology for your connected devices before rolling out a large estate of cellular-connected devices.

Smart Roaming checks not only signal strength but also ‘ping times’ and ‘ping completion’ to build a more complete picture of the current connection. If the Health Check fails, 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’.

Smart Roaming v2 extends the original functionality that was solely focussed on resilience to enable more intricate manipulation of Roaming SIMs and most importantly, a built in speed test that allows users to make a real-time assessment of the quality of the internet connection.

New Features in Smart Roaming v2

1 – the original v1 Smart Roaming was designed just for resilience. If automatic network selection did something illogical/unfavourable, then Smart Roaming would override the embedded network selection process and manually attempt to move the connection onto other networks to fix the issue. For industrial applications with little concern about data speeds this is perfectly adequate. One of the key upgrades in Smart Roaming v2 is the ability to check data throughput speeds with a speed test and manually (user controlled) change to another network if the current network is too “slow”. This is enabled by a network selection feature and a speed test feature all managed through the router’s GUI.


2 – Smart Roaming v2 also allows “preferring” of networks. This is an expert option that only affects Automatic network selection but in some applications it may be preferable to load the dice in this way.

Please take advice from Robustel’s Tech Support team before using this option.


3 – Smart Roaming v2 features a “Forget RPLMN” button. Clicking this will erase all memory of the RPLMN, or “last known good network” as its commonly known. Just like point 2, this is an expert option that needs to be well tested with the target SIM before rolling out a large estate.

Removing the RPLMN (stored in the SIM) then rebooting means the automatic network selection process will not be jaundiced by what has happened previously. In essence, automatic network selection will treat the SIM as it had never been used before and hence it will choose from good quality networks after a scan, at random.


4 – Complete remote control. Everything that can be done in the router interface can also be achieved remotely with SMS commands. This means that a large estate of routers can be securely monitored and managed remotely using a cell phone. No other tools required. SMS Examples below:

Getting Started with Smart Roaming V2

For a demonstration, access to documentation and set-up assistance please click the button below to contact Robustel to be introduced to a local partner.


Or read our updated white-paper on Smart Roaming:

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