IoT connectivity protocols form the language of an IoT system, and just as a language develops over time to serve the needs of the people who speak it, IoT protocols are evolving to better suit industrial networks and their users.

Over the years, more and more IoT connectivity protocols have been developed. Some are created to answer to specific needs that weren’t supported by legacy systems, while others are an attempt by developers to create a new standard that can be widely adopted.

When it comes to the “how” behind an IoT system, one of the defining factors is the type of communication protocol the system uses. Deciding on the correct protocol early on is critical for building a successful connected product.

Your choice of networking protocol will impact the design of your connected product, and the entire IoT system that it’s a part of.

To help you make sense of IoT network protocols, and gain a better understanding of network systems in general, here’s a breakdown of connected systems all the way from the ground up.


An Overview of Network Types

Before we get to the specifics of IoT connectivity protocols, let’s review a few of the basic network types, as organized by the range of communication they offer.

PAN – Personal Area Network

Starting with the smallest network type, a PAN often relies on Bluetooth or WiFi connectivity to link up a number of personal devices such as a laptop, printer, media system and so on. The radius of a PAN network may be as small as the size of a room or part of a house.

LAN – Local Area Network

As the name suggests, a LAN is also a relatively small network, usually covering a home or office-sized area, either by use of cable or wireless technology such as WiFi.

WAN – Wide Area Network

The main difference between a LAN and a WAN is scale, although there is no typical size definition for a WAN. Anything from a college campus linking multiple buildings to each other to a global corporation using satellite communications can be regarded as a WAN.

VPN – Virtual Private Network

In many cases, we’d like to restrict access to our network while allowing authorized users the ability to access the network from remote locations. A VPN allows us to do just that by encrypting the connection process.

MAN – Metropolitan Area Network

As the name suggests, this type of network connects users and devices within a defined metropolitan area. A common technology used by MANs is microwave transmission which is facilitated by dedicated microwave antennae.


Mesh Networks in Industrial IoT

Networks can be described according to their connectivity configurations, also known as topologies. For example, a star network will have a central hub through which all other nodes are connected

Mesh networks have a number of advantages since they allow for every node to be connected to every other node in a more direct manner. This reduces maintenance costs and helps prevent communication issues since the data has more than one way to travel between two points, and doesn’t have to go through the hub. For this reason, mesh networks are proving to be an excellent and popular IoT connectivity solution.

IoT Network Topologies


IoT Protocols and the Internet

To get a better grasp of IoT protocols, it helps to understand how they fit into foundation network systems. Now that we’ve got some of the basics out of the way, let’s take a look at broadening our connectivity ecosystem even further. To do this, we have to make sure that our individual networks can communicate clearly with one another.

It would be useful to have a set of protocols and rules for data transmission for the variety of network types to ensure that the information can be shared. For this reason, the TCP/IP and OSI models were created. These models describe network systems as being made up of a number of layers, each with its own set of protocols and functionality.
IoT Protocols and the Internet - TCP/IP Vs. OSI

TCP/IP – Transmission Control Protocol/Internet Protocol

The TCP/IP was developed in the United States by the Defense Advanced Research Projects Agency (DARPA) in the 1970s. It was created for the Unix OS for use in ARPANET which was a WAN that existed before the internet.

TCP/IP is based on a client-server communication model by which a user (client) receives a service such as a loaded web page from a server in the same network.

The TCP/IP is divided into 4 layers per functionality, with each layer having its own set of protocols.

Application Layer

Facilitates standardized data exchange for use by applications.

Transport Layer

Provides end-to-end communications and monitors reliability, message order and prevents congestion across the network.

Internet Layer

Manages the use of addresses for routing message packets over the network. For IoT device connectivity, IPv6 is the protocol most commonly used on this layer.

Physical Layer

As the name suggests, this layer represents how various devices are physically connected to the network ie. which type of hardware or cables are used to create connections between nodes and hosts.


OSI – Open System Interconnection

The OSI is the successor to TCP/IP and the two are often compared as there are a few parallels between these models. Since the OSI model contains a few more layers, it can be said that in general, it allows for a more detailed breakdown of the internet structure, describing the path taken by data as it travels back and forth between users and servers.

The Application Layer

Not to be confused with the actual application, this layer provides a set of services that an application can make use of. The application layer identifies nodes that are actively searching to communicate. It assesses whether those nodes are ready to transmit or receive data, and assists in the sending and opening of the actual data file.

The Presentation Layer

Usually contained within an operating system, the Presentation Layer converts data from one format (presentation) to another for both outgoing and incoming transmissions. For example, a regular text will be encrypted before being sent, and then converted once again to readable text on the receiving end.

The Session Layer

The Session Layer coordinates and terminates conversations on the network. This layer is also responsible for authentication and for re-establishing a connection after an interruption takes place. For most applications on the internet, Session Layer services are handled by the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).

The Transport Layer

To move data from one point to another, the Transport Layer places it in “packets” which it then delivers. This packetization process allows the Transport Layer to check for errors that may have occurred in the communication process. Like in the Session Layer, Transport Layer services are also handled by the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).

The Network Layer

This layer acts as a logistics hub, routing data and assigning addresses, and making sure that packets reach the right destination. For the internet, Network Layer activities are handled by the IP.

The Data Link Layer

This layer, represented by the Ethernet, has a number of functions, starting with the framing of data packets and their organization. The Data Link layer has 2 sublayers: the Media Access Control (MAC) layer which manages data flow control; and the Logical Link Control layer which checks for errors.

The Physical Layer

This layer describes the hardware used to send and receive data across the network, whether that be by electrical cable, fibre topics or by some form of wireless connectivity method.

IoT Connectivity Standards: Common Protocols

Now that we’ve covered the basic anatomy of connected systems, let’s zoom in on networks specifically implemented in Industry 4.0 use cases. Since some of these protocols overlap more than one network layer, and because of the differences between the TCP/IP and OSI models, the list below offers general groupings.

Here are the most common industry 4.0 connectivity protocols used by industrial IoT networks today…


Application Layer IoT Protocols

MQTT – Message Queuing Telemetry Transport

MQTT, previously known as the “SCADA protocol”, is a lightweight, easy-to-implement messaging protocol. MQTT works by means of publish-subscribe, and is particularly useful for remote communication and in cases where bandwidth is limited. MQTT is ISO-approved and offers low power consumption and efficient data distribution via its minimized packet system. This makes it a great option for industrial IoT and mobile applications.

AMQP –  Advanced Message Queuing Protocol

AMQP is an open-standard message protocol that facilitates the queuing, routing and orientation of messages in a secure and reliable manner. AMQP is feature-rich, providing superb interoperability across a broad range of messaging applications.

CoAP – Constrained Application Protocol

The CoAP protocol was created specifically for connecting devices with limited (constrained) resources such as a small memory or short battery life. Additional extensions have been designed for use with CoAP that offer extra features that can reduce transfer times and define several CoAP resources as a group.


Internet/Network Layer IoT Protocols

IPv6 – Internet Protocol Version 6

Developed by the Internet Engineering Task Force (IETF), IPv6 is the most recent version of this communication protocol which routes traffic across the internet, locating and identifying computers on various networks.

6LoWPAN – IPv6 Low Power Wireless Personal Area Network

This protocol allows for IPv6 to be used with 802.15.4 wireless networks – a standard developed by the IEEE. 6LoWPAN gives IoT connectivity to low power devices.

RPL – Routing Protocol for Low power and Lossy Networks

RPL is a routing protocol that has been optimized for networks that include wireless sensors. RPL, pronounced “ripple”, was created especially for cases where not all the connected devices can be reached at all times. RPL minimizes energy consumption and latency by calculating the best routes for communication between nodes.


Physical Layer IoT Protocols

LPWAN – Low Power Wide Area Network

As the name suggests, devices employing LPWAN can transmit data over long distances while having low power consumption.


Existing cellular technologies have and are still being used in IoT cases, although legacy protocols such as GSM and CDMA are slowly being phased out. Narrowband-IoT (NB-IoT) along with LTE-M are newer standards that were developed especially for running IoT systems using existing cellular networks.

Bluetooth Low Energy (BLE)

BLE is a version of the well known Bluetooth protocol with a number of distinct differences. It saves power by transmitting in bursts, and is typically used for devices in a star configuration with a range of under 100m. BLE is a popular choice for wearable IoT devices especially those aimed at the consumer market such as fitness trackers.


Zigbee is a suite of connectivity protocols and hardware especially designed to be low-cost and low-power as a simpler and cheaper alternative to Bluetooth. Despite its limitations of low data rates and a short range, Zigbee is used for both consumer and industrial applications with specifications that fall under these constraints.

NFC – Near Field Communication

NFC allows for the transmission of data between two devices that are within close range of each other (up to 4cm), but without making contact. Typical applications of NFC will include the use of a smartphone or other types of mobile devices such as contactless payment systems, keycards and electronic tickets.  

RFID – Radio Frequency Identification

RFID uses electromagnetic signals to detect chips containing electronically stored information placed within objects. RFID chips can be either powered or passive and because they work on radio frequencies, do not require a direct line of site between tag and reader.   


WiFi technology enables IoT wireless connectivity over a LAN using IEEE 802.11 standards. As alternative wireless protocols emerge with lower power consumption and longer ranges, it is likely that we will see a decline in the popularity of WiFi.


Ethernet is based upon the IEEE 802.3 standard and is widely used to build LANs. IoT networks do not necessarily have to be wireless and by using Ethernet, an IoT system can be built upon existing electrical cable networks.


Choosing the Right IoT Connectivity Protocol

Selecting the right IoT connectivity protocol for your project might seem a bit overwhelming at first, but after understanding a few core principles, and by matching those with the needs of your system, this task will become much simpler.


The distances over which communication between the various devices in an IoT network takes place.

Using a protocol designed for short-range transmission obviously won’t be suitable if your project requires communication over long distances. On the other end of the scale, short-range protocols can be useful in cases where security is an issue by limiting the physical range of communication.  


The volume of data that’s transferred in a given time period.

Every type of protocol has its own defined packet sizes for transferring data. The volume of data in a transmission that would typically occur in your IoT system should match the packet size that your chosen protocol can handle. Having a protocol with packet sizes that are too large is inefficient while packets that are too small will lead to data blocks having to be divided up, leading to unnecessary processing.


The ability of a connected device, app or sensor to communicate with another, usually from a different manufacturer or host.

As technology advances it’s important that our systems are backwards compatible to avoid components becoming obsolete. IoT connectivity protocols also need to be able to integrate elements that aren’t from the same manufacturer.

Data Rate

The rate at which data can be transmitted over a network, measured in Kbps or Mbps.

This parameter is closely linked to bandwidth and range and is of course an extremely important factor since in our IoT system we will want our data transported with as little latency as possible.


Measures taken so that data is protected during the various stages of transmission, as well as during storage.

When we transport data from point A to point B it becomes vulnerable, and this is a major concern amongst companies working on introducing IoT connectivity to their products. Thanks to advances in security technology, there are many methods in place to ensure that IoT networks are protected including encryption, authentication and port protection.

Power consumption

The power consumed by a device when data transmission takes place.

Power consumption is not only a critical factor to take into account when designing products powered by batteries, but also for making sure operation costs are kept in check.


The ability of a protocol to continue to perform as the network grows in number of connected devices.

When choosing an IoT connectivity protocol it’s important to keep in mind that your system is likely to grow. Scalability ensures that as devices are added, the quality and responsiveness of your network will be maintained at a high level.

By creating a brief that includes the needs and specifications of your IoT project based upon the above factors, you will be much closer to deciding which protocol is suitable.


Meeting the Challenge of Industry 4.0 Connectivity

At the heart of the Internet of Things is the idea of seamless connectivity – multiple devices collecting and transferring data to one another, to a cloud, and to people who use data-driven insight to make important decisions.

Experts predict that by 2020, anywhere from 20 to 50 billion devices will be connected and active components in their respective IoT ecosystems. This exponential growth requires that connected devices demonstrate a high level of compatibility, reliability, and security.

Nowhere is this more important than in the industrial sector where the level of accuracy of data transmission not only affects operational costs and revenue, but also employee safety.

For more information about industrial IoT connectivity, make sure to visit our library of free IoT resources.

If you’re looking for a way to advance to Industry 4.0 without the risk or the headache, feel free to contact us to find out how the Seebo platform can help you achieve your IoT goals.

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