The Internet of Things is packed with terminology. Roamit helps customers navigate the jargon by providing this keyword glossary. Helping to demystify the Internet of Things and give an understanding of all it’s different components.

Expand your knowledge of cellular IoT through commonly used terms — from Multi-IMSI to NB-IoT and beyond.


3g sunset

As 4G technologies mature and 5G deployments accelerate, mobile network operators are becoming less reliant on 2G and 3G technologies — both for data and, more recently, for voice. This change provides an opportunity to re-allocate radio spectrum from 2/3G to 4/5G.
The phasing out of these legacy (2/3G) technologies is commonly referred to as their sunset.

3rd Generation Partnership Project (3GPP)

3GPP is a collection of mobile telecommunications organizations that develop standards. They develop and maintain specifications for core network and service capabilities as well as radio access technologies.


5G is the fifth-generation broadband cellular network design, first introduced in 2016 and deployed in 2019. It is intended as the global successor to the 4G network. For a network to be considered 5G by the 3GPP, it must support a new radio access technology (RAT) called 5G NR (“New Radio”). 5G NR uses OFDM for modulation but offers significantly more total bandwidth than 4G (LTE). Additionally, a 5G base station (tower) may optionally support millimeter wave frequencies known as 5G FR2 (“Frequency Range 2”), which enables shorter-distance and higher-throughput data transmission.

Application Programming Interface (API)

An IoT API is the tool software developers use to gather and transfer data from one application or computer to another. APIs enable developers to programmatically interact with software components both inside and outside of their own code.

Access Point Name (APN)

An APN allows a connection to the internet through a cellular network. It can also help separate traffic from other networks and defines the set of connectivity rules a device has as well as certain security measures. All cellular connected devices use either a public or private APN of some kind.


Bandwidth is defined as the maximum amount of data that can be transmitted over an internet connection in a specific range of time. In IoT bandwidth needs vary by use case.


Cat-M1 is a radio access technology that was designed specifically for IoT projects to transfer low to medium amounts of data across a wide geographic range. It is also known as LTE-M.

Data plan

IoT data plans provide access to cellular data for devices. Unlike consumer cellular plans, they’re uniquely structured for use case and business needs. Good data plans take into account the number of devices, whether or not data usage will fluctuate, fleet location, and any additional tools or features provided.

Data pool

An IoT data pool allows businesses to buy a set amount of data for a group of devices, rather than paying per device. This is often used when some devices use a lot of data, while others use little.

Device certification

IoT device certification ensures that all devices on a cellular network meet security and interoperability requirements. Different kinds of certifications are required depending on where devices will be deployed and what carriers will be accessed.

Edge router

An edge router is a device that connects an internal network to the internet. They’re used at the edge of your network, where your private network ends and the public network begins.

Embedded SIM (eSIM)

The eSIM is a SIM card that is soldered directly to a board inside a device. The eSIM is the hardware component that allows for cellular connectivity, whereas eUICC is the software component or operating system that allows for over the air updates.

Embedded Universal Integrated Circuit Card (eUICC)

eUICC is the software component that provides the ability to issue over-the-air (OTA) updates to SIM cards. eUICC-enabled global IoT SIM cards allow teams to build with one type of SIM card and deploy to different locations around the world. They come in multiple form factors.

Integrated Circuit Card ID (ICCID)

The ICCID is a globally unique serial number consisting of 19 or 20 digits that identifies a SIM card.

International Mobile Equipment Identity (IMEI)

An IMEI is a 14-digit number that serves as a distinct identifier for cellular devices.

International Mobile Subscriber Identity (IMSI)

An IMSI is a 15 digit number that determines a subscriber’s country of origin, mobile service network, and specific device identity.

Internet Security Protocol (IPSec)

IPSec is a set of protocols between two points on the IP network that provide data authentication, integrity, encryption, decryption, and confidentiality.

IoT cloud

IoT cloud platforms are end-to-end services that provide the infrastructure for transmitting, computing, and storing data from IoT devices.

IoT connectivity

IoT connectivity links all of the elements of an IoT ecosystem and allows devices to send and transmit data. Common IoT connectivity types include cellular, Wi-Fi, ethernet, Bluetooth, RFID, and more.

IoT platform

An IoT platform is a software as a service (SaaS) product that can oversee a fleet of connected devices. Its features vary from product to product, but may include insight into device connectivity and location as well as the ability to manage devices and view connectivity billing information.


Latency measures how long it takes for data to travel from one point to another. Low latency means data is transferred quickly between device, network, and the intended outcome.

Low-Power Wide Area Network (LPWAN)

LPWANs are network technologies designed for minimal power consumption and the ability to achieve long-range communications. This includes NB-IoT and Cat-M1 among others.


LTE-M is a radio access technology that was designed specifically for IoT projects to transfer low to medium amounts of data across a wide geographic range. It is also known as Cat-M1.

Machine-to-Machine (M2M SIMs)

M2M SIM cards — also known as IoT SIM cards — are pieces of hardware embedded or inserted into devices that enable connectivity and allow devices to send and receive data across cellular networks.

Message Queuing Telemetry Transport (MQTT)

MQTT is a lightweight messaging protocol designed for IoT. It works well for sending messages to control outputs or read sensor data.

Multi-Access Edge Computing (MEC)

MEC is a kind of computing that processes data closer to where it is gathered, rather than in a central data center.


Multi-IMSI technology allows several IMSIs, or International Mobile Subscriber Identities, to be loaded on a single SIM. SIMs cycle through profiles until an available network is identified.

Mobile Virtual Network Operator (MVNO)

An MVNO is a connectivity provider who has negotiated agreements with several mobile network operators (MNOs) to gain access to multiple networks.

Native connection

A native connection allows devices to access cellular data directly from the MNO that owns the infrastructure, rather than via a roaming connection. Native connections typically provide greater performance at a lower price than roaming profiles.


NB-IoT is a low-power, wide area network (LPWAN) technology that operates on the licensed spectrum and wass designed for IoT devices with low-bandwidth needs.

Network redundancy

Network redundancy is an overlap of cellular coverage in case an IoT device travels outside of the original coverage area or the primary network experiences a disruption.


PTCRB is a standardized framework for device certification. The program verifies compliance with 3GPP network standards.

Point of Presence (PoP)

A PoP is a place where two or more networks or devices share one connection. PoPs are established local access points that allow for online communications and form the foundation of how we connect to the internet.

Radio Access Network (RAN)

The RAN is responsible for the connection between devices and the core network and implements a RAT. For example, UTRAN radio access networks implement UMTS and E-UTRAN radio access networks implement LTE.

Radio Access Technology (RAT)

A RAT is the physical layer of a radio (cellular) connection, such as UMTS (3G) or LTE. A single device may support multiple access technologies. A RAN implements a RAT.

Remote SIM Provisioning (RSP)

RSP ensures the SIM is accounted for in the databases that will determine whether or not it has the permissions to attach to a particular network or to a particular carrier. Beyond the initial SIM registration, provisioning can also include enabling the correct profile on a multi-profile SIM, or activating profiles on the SIM so they are ready to connect to the cellular network.

Roaming connection

IoT roaming agreements allow devices to use multiple networks to access cellular data, rather than using a singular network. Roaming connections can often provide greater coverage and redundancy than native connections.

SIM card form factors

A form factor is the standardized size and specification of SIM card. For IoT, form factors include Mini SIM (2FF), Micro SIM (3FF), Nano SIM (4FF), and Embedded SIM (MFF2).

Short Messaging Service (SMS)

SMS is a method of exchanging short text messages. SMS is commonly used in IoT to send command, configure, and control messages.


Throughput is the measure of how much data can be downloaded or uploaded through the network at any particular time.

Type Allocation Code (TAC)

The first eight digits of an IMEI make up the TAC. This indicates the manufacturer and model of the particular device. All device models from one manufacturer will have the same TAC.

Virtual Private Network (VPN)

A VPN creates an encrypted tunnel between data centers and their encrypted devices.