The next generation of 3G/ 4G reliability and roaming with SIM Management from Robustel is here!
As champions of Robustel for many years now, our clients are now benefiting from a new technology known as Smart Roaming which is available exclusively within Robustel Routers and increases 3G/ 4G connection reliability to the levels required by IoT and M2M solution providers.
Previously, Multi-network (roaming) sims have often been offered as a solution to intermittent GSM communications, but this is only 50% of the solution as roaming sims give access to all 2G, 3G and 4G networks in any one country. However, network selection is a function of the hardware and 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.
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 innovation has meant that the cost of site visits has been drastically reduced and provides peace of mind to the client as they know they have implemented the ‘highest reliability’ Comms methodology for their 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 establish 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.
As well as understanding the benefits of Robustel, you must also understand the different types of Sims that are utilised within M2M/ IoT applications:
Single Network Sims
These SIMs provide coverage on a single network typically in a single country. This means that if there is no coverage on the network at the installation location (especially if it is in a building) then the communications will not work. Additionally, if the deployment is multinational then lots of different SIM agreements for different territories need to be agreed which is logistically difficult and virtually impossible to manage at scale. The traditional solution proposed to these problems has been to offer a roaming or ‘multi-network’ SIM typically offered by aggregators. What most people don’t realise is that not all roaming SIM cards are equal!
Steered Roaming Sims
Steered Roaming Sims ‘can’ access multiple networks per country but will favour a specific network or subset of networks for the mobile operator’s commercial benefit. The majority of the time, steering it is not implemented for the benefit of reliable communications but to make the scheme less expensive by using ‘preferred’ networks. This is generally the opposite of what is wanted by IoT service/system providers who need as close to 100% network uptime as possible. Steering of roaming is a complex subject matter not covered in this document. The primary and simplest solution is to select a good quality un-steered roaming SIM although clever marshalling of steered roaming schemes can help to achieve desirable commercial outcomes.
Un-steered Roaming Sims
As the downsides of Steered roaming have become more visible in the market, certain mobile service providers have started to provide and champion un-steered roaming sims. This has meant that the sim has no preferred network lists onboard and does not suffer operator-side steering at the network level. Essentially, an un-steered roaming sim is a 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 / reliability is key.
As mentioned earlier, Sims do not play an active role in network selection; choosing an appropriate network is a function of the hardware and/or how the hardware is told to behave by associate firmware such as AT Commands. There are 2 different types of network selection;
Automatic Network Selection
With automatic network selection, the device selects and attempts registration on other PLMN/ Access technology combinations. These network selection rules were originally defined many years ago and do not use the ability for TCP/IP communications to work as an indicator of a usable network. This means the cellular device could be on a network with good signal strength but due to other reasons there is no ability to transmit data. This is extremely undesirable for any IoT/M2M service provider. Another critical point is that prior to this selection process, the hardware will always try to use the “last known good network” or RPLMN (Registered PLMN) which means that even a reboot will not necessarily push an unconnected system into a working state. The RPLMN concept could mean that a router keeps attaching to a network without working Data Comms due to the failings of the automatic network selection process. Net effect of this is quite simply loss of Data comms. This very obscure point is commonly not understood and has big implications for those expecting everything to ‘just work’ when a roaming SIM is used with automatic network selection. The automatic network selection process has no empathy for packet-switched Comms so an application that sees good signal strength but cannot communicate with a server on the internet will continue in a state with no connectivity and will not automatically recover. To avoid this problem, some supplementary logic is required in the device firmware. It is this fundamental issue that Robustel’s ‘SMART Roaming’ Application aims to solve using the simplicity of Automatic network selection but supplementing it with Health-checks and the use of Manual network selection to make sure reliability is as high as it possibly can be.
Manual Network Selection
In comparison, manual network selection is relatively very simple as compared to automatic network selection. A device can request connectivity on a specific network and so long as registration for the appropriate services is allowed by the SIM/provider, then a connection is made. At this stage, it would be reasonable to ask, “Why don’t all M2M applications use manual network selection?” A lack of understanding by hardware manufacturers combined with a relatively high level of risk / complexity in the development process for such subroutines means many shy away from adding such ‘polish’ to their connected products. Robustel’s ‘SMART Roaming’ overcomes the limitations of Automatic Network selection to allow Cellular IoT Devices that require high uptime to connect with confidence.
So, with all that being said, what does Robustel Smart Roaming V2 bring to the table?
Speed Based Network Selection
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 was 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.
Preferred Networks
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. Point (ii) from Figure 2.0 refers to the list in the SIM that is edited with this command.
Clear Network Cache
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 3, 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.
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.