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What is an IoT Router?

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What are the differences between IoT Devices, IoT Routers, IoT Gateways and IoT Modems?

IoT devices, short for Internet of Things device, is a piece of technology that is connected to the internet and can communicate with other devices. These devices can range from vehicle telematics boxes, smart thermostats and wearable trackers to smart home security systems and industrial sensors. The beauty of IoT devices lies in their ability to collect and exchange data, making our lives more convenient and efficient. From monitoring our health to managing our energy consumption, IoT devices are revolutionising the way we interact with technology in our daily lives. Generally they use mobile connectivity directly to the GSM cellular mast, authenticated by a IoT SIM card.

Routers are products and devices that are commonly used at home and in business for connecting devices on local area networks (LAN), securely and cost-effectively to a variety of wide area network (WAN) infrastructure types [such as such as national PSTN/ISDN/IP or GSM networks]. In these settings, LAN connections are most often provided through wired ethernet, or wirelessly through local Wi-Fi. 

Routers are, therefore, used to provide user-based connections for business offices, retail stores, homes and domestic properties, housing associations, and care homes. This is most typically for devices such as work computers, phones, tablets or attended specialist devices that rely on typical standard LAN protocols; for example, such as handheld payment terminals or till systems. They are also used for connecting site-services such as security cameras, CCTV, vending/ticket machines and self-service kiosks.

IoT Gateways are similar to routers but are more specialised. Used for connecting IoT devices locally, providing secure, aggregated, managed connectivity to a WAN. Typical types of devices include alarm systems, environmental/motion sensors and wearables. 

IoT gateways are more designed for connecting standalone sensing objects or devices which require the use of low power local networks such as Bluetooth Low Energy (BLE), ZigBee, Z-Wave or LoRa-WAN. This is due to the need to preserve the longevity of power for battery powered or low voltage IoT devices and sensors. These types of devices also need secure remote configuration as they have little scope for on-site human intervention. They tend to be therefore managed by IoT platforms that are specially designed for managing IoT Gateways and IoT sensors. 

They, also, often utilising abstraction layers which enable a large variety of IoT sensor device hardware to communicate using standardised protocols such as MQTT at the WAN uplink level (MQ Telemetry Transport) being a lightweight, publish-subscribe, machine to machine or machine to cloud network protocol. 

By virtue of the types of sensors and devices they are used to connect, IoT gateways have tended to historically use less data and bandwidth than routers [which may be used for streaming video, or uploading/downloading large files to computers, phones or tablets]. 

This, however, is changing as IoT devices become more intelligent and complex. Both routers and IoT gateways often utilise secure mobile as a primary or back-up communications method to ensure maximum resilience or the benefits (cost, inconvenience of installation and maintenance) of not requiring fixed-line installations (Fagerberg, 2021).

IoT Modems are the chipsets or integrated components that IoT gateways use for connecting to a variety of WAN networks. They provide an efficient and easily configurable set of control commands using standards such AT (Attention) commands which are used by devices to control GSM modems. Routers also use Modems, but IoT versions can be more specialised or low power versions depending upon the intended context.

Handheld POS terminals also often rely on short-range wireless connectivity solutions such as Wi-Fi or Bluetooth. Increasingly they incorporate mobile GSM to benefit from independence from unique site contexts or unsecure local networks and to provide maximum range flexibility (ibid).

IoT Solutions and Connectivity

Industrial IoT and commercial IoT solutions often need a combination of connectivity techniques. This is due to the nature of sensor devices, their use cases, power budgets, local physical environment and bandwidth considerations. An IoT application may need direct cellular IoT hardware solutions, WiFi, edge router solutions, industrial routers, more physically rugged series routers, and redundant connectivity options. It is therfore important to talk to IoT experts to get the optimum combination of connectivity and hardware for the business need or use case.

What are the Reasons for Implementing Routers with Mobile Connectivity?

Routers are increasingly utilizing mobile connectivity for both fixed location and mobile applications. For example, fixed location includes offices, retail outlets and homes, whereas mobile applications include the provision of Wi-Fi on trains, river cruises, motorhomes and caravans.

Mobile connections in fixed location applications are principally used as a fail-safe or back up, or where broadband wired connections are unattainable. Devices are available in a range of options, including dual SIM and dual Modem. This provides the ability to connect to multiple networks and to utilise more than one mobile network at the same time to increase bandwidth availability. This also, clearly increases router resilience, but is more expensive in terms of hardware.

Mobile applications such as trains and cruise ships, obviously utilise mobile connections as their primary method of providing connectivity for business applications and for providing paid for Wi-Fi to passengers. These systems also sometimes utilise satellite uplinks, although they tend to be costly in terms of data rates. 

Many caravanners and motorhomes are also increasingly becoming more self-sufficient in terms of connecting their vehicle or family while on holiday or on extended breaks. This can be vital if continuing to work while located at their ‘second home’. While many may simply connect devices through their consumer phone/SIM card, others who are travelling to more difficult or remote locations desire multi-network connectivity or the assurance of an installed router/wi-fi which all devices can be connected to. By using an IoT SIM, the data use can be more actively monitored and managed whether through a portal or APP.

What are the Reasons for Implementing IoT Gateways with Mobile Connectivity?

IoT Gateways also require mobile connectivity in both fixed and mobile applications. Fixed location use cases include building or home monitoring, medical monitoring or home wards, telecare, assisted living, building security systems, refrigeration monitoring, and environmental monitoring. Mobile applications can include cold-chain distribution systems and logistics systems, or caravan monitoring in terms of security alarms, safety and environmental alarms. 

Typical IoT devices used in either mobile or fixed-location cases include motion sensors, temperature and humidity sensors, fire alarms, Carbon Monoxide and Dioxide alarms, heat alarms, fall arms and emergency buttons. One of the complexities of mobile IoT routers, which typical involves installation within a form of vehicle is understanding of the complexities of vehicle power scenarios and how to manage vehicle and gateway battery lives during different power up and power down cycles. This can involve power spikes which can damage devices, or down-times which are beyond the capabilities of battery capacities or UPS devices. 

For fixed locations, IoT gateways used in mission critical applications such as telecare, may also need to conform with telecare standards which can require battery back-up for as long as 8 hours in the event of a power failure. 

Given that IoT gateways need to continue to communicate in a range of installations and scenarios, utilising mobile IoT connectivity either as the primary or fail-safe connectivity option is an attractive choice. It can also mean that IoT gateways might consume less power when it becomes unavailable and that is the main in-built connectivity option. Gateway populations can also be moved around more freely as the needs of buildings and users change, without the need to reinstall fixed line connections or interrupt a third party or hosts building fabric or decorative finishes. 

Despite these challenges, the uses of cellular enabled IoT Gateways are increasing, with Berg Insight research affirming over 4 million gateways being delivered in 2021, with this forecast to grow to over 7 million by 2025 (Stålbrand, 2022).

How do Routers and IoT Gateways Attain a Seamless and Reliable Service by using Cellular Connections?

Routers and IoT gateways are manufactured by OEM manufacturers for a variety of clients and use cases. The firmware logic that manages and controls the router or IoT gateway hardware will also manage their communications. This might include configuration changes that are available through a remote management system or portal. The methods that their firmware and configuration enable routers/gateways to select their method of communication is key. 

The ability to securely tunnel or use Fixed IP VPN for changing parameters or updating firmware is also vital to ongoing security and resilience. The capability to initiate or perform power cycles or tasks can also reduce maintenance visits. Using mobile/GSM/Cellular connectivity can not only provide these secure methods of connection but can also mean that devices are still contactable when the fixed line communications are interrupted or cut. It can also mean that they are contactable and actionable in the event of a power failure, provided it is within the window of battery or UPS back-up.

What Roles do IoT SIM Cards Play?

For business-critical applications, any Wi-Fi options need to provide a secure and manageable connection. If not correctly set up, a simple local configuration change could render devices unable to communicate or be open to malicious or fraudulent interception. Positioning of Wi-Fi routers also needs to cover all required needed spots in the building. This can be more of a problem for providers who lack the IT skills or control the premises in their entirety.

For these reasons, service providers are now using IoT SIM Cards as the primary or secondary forms of communications for many of their router and IoT gateway devices. This is increasingly as the back-haul mechanism for Wi-Fi routers.

This provides the best of both worlds in terms of reach, but also provides multiple forms of communication resilience. Enabling portable and static devices and systems to secure their critical connectivity and eliminate single points of failure.

For deployment simplicity and resilience, most rely on secure multi-network mobile connectivity, providing geo-resilience in deployment and for a maximum combination of service up-time and deployment flexibility.

How do Multi-Network IoT SIM Cards Help Routers and IoT Gateways Work More Securely and Reliably?

Multi-Network systems enable devices to communicate using any of the locally available mobile radio mast access networks. For example, in the UK, which would mean EE, Vodafone, O2 and 3; or a subset of these depending upon price and availability. 

This provides maximum geographic flexibility for national deployments and the ability to communicate using whichever local radio network is the strongest or most available in terms of data throughput. Normal consumer SIMs do not allow this and are fixed to one provider. 

This means that if a signal from a network provider is poor in a location or attenuated due to building conditions, or is suffering a local or national outage, then a device loaded with an IoT SIM card can hop to another network.

To work reliably, however, it is important to select devices that can intelligently select the most appropriate network for their needed type of communications and based upon network availability. Gateway devices are manufactured with integrated modems which support a variety of GSM radio frequencies and protocols for certain types of mobile communications. 

If, for example, the device modem only supports 4G LTE communications and not 2G or 3G, but the strongest signal available is a 2G one, then the device if (as many are) configured in firmware to select the strongest signal (dBm) would therefore select the 2G [very low or no data] network, when a slightly lower strength 4G signal but higher data bandwidth network is available. 

It is not unknown for devices to hang onto these 2G networks as devices will usually only switch if the 2G network signal strength (dBm) drops below certain threshold. This can be particularly catastrophic as the device may never have cause to try another network. For multi-network IoT SIM cards to work effectively, it is therfore imperative that manufacturers configure their network selection processes in consultation with IoT SIM card providers and experts.

Dual-SIM Options?

Multi-network IoT SIM cards deliver significant resilience over single-network SIM card performance for gateway or edge systems. Dual discrete-pathway multi-network IoT SIM cards, however, can also be selected for an even more resilient option.

Multi-network SIM cards provide access to all radio access mobile networks locally available. The signalling pathways for all traffic over these networks must, however, be authorised by a single IoT roaming agreement provider using their core infrastructure and Home Location Register (HLR). The highest quality systems are designed for high resilience, geo redundancy and are supported by sophisticated Network Operation Centres (NOC). 

Even the highest quality systems, however, can sometimes suffer temporary outages or suffer service degradation during pre-warned maintenance windows. If the core systems are interrupted for some reason (although rare), then data sessions cannot be authorised. 

Two SIM cards by two different and discrete IoT core infrastructure roaming providers, therefore, offers the potential for complete end to end and temporal resilience as it is highly unlikely that both network roaming provider’s core infrastructure would degrade at exactly the same time.

For the absolute maximum possible theoretical levels of resilience, two IoT Multi-Network SIM cards can be used as the primary/back up, independently or in conjunction with Wi-Fi or wired LAN communications. This, however, requires intelligent dual SIM support in the terminal hardware and intelligent dual SIM capability and network selection to be implemented within the device’s hardware and firmware. It may also require remote configuration for the client to select their preferred parameters. For example, implementing a Dual SIM approach means the hardware and firmware of the device must support and manage the utilisation of both SIM cards. 

In some cases, two SIM slots may be supported in the hardware, but this does not mean that the device manufacturer has implemented the firmware to support both. They may not have also implemented software that intelligently manages switching between the two SIM cards based upon fully thought through real life scenarios. Switching SIM cards unnecessarily, could create problems. For example, during a successful transaction.

Control of or influencing the hardware and firmware design of devices becomes imperative for both security and resilience. It is important for the device to not only make informed decisions in-session and between sessions, but also to ensure that the device is monitoring and selecting networks in-between transactions or during device down-times to ensure that the device is connected and ready for use as soon as it is needed for transactions. 

Any loss of a particular network would therefore be dealt with proactively and in advance of the service being interrupted. For example, implementing heartbeats can mean that any significant network problems can be dealt with proactively, but also based upon the surety of an appropriate number of retries before SIM switching. 

Having a sophisticated implementation also means that the data plans for each SIM card become more predictable and creates a more cost-effective cost plan environment for each.

Where a dual SIM hardware/firmware option does exist, it is important, therefore, to test the functionality based upon a number of live-use scenarios. As a guide, switching core networks can take anything from 15 seconds to well over a minute. It is, therefore, best to only switch SIM slots under known and controlled circumstances; i.e. when a catastrophic connection failure is detected and verified by the device. 

As an alternative, Dual modem/SIM options are also available which can connect to two networks simultaneously for maximum temporal resilience.


When it comes to choosing the right IoT routers for your business, Caburn Telecom and it’s parent company CSL Group stand out as the top contenders in the market. With their unrivalled expertise and technology, they have proven time and time again that they are the best option for businesses looking to connect their devices seamlessly and securely. Caburn Telecom’s cutting-edge solutions offer unmatched reliability and performance, together with CSL Group’s innovative approach to IoT networking ensures that your data is always safe and protected. Trust in Caburn Telecom and CSL Group for all your IoT router needs, and experience the difference for yourself. To see more of our success stories and CSL IoT routers and their case studies, please click on the following links: Managed IoT Routers


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