Over the past two decades, Zigbee has established itself as the dominant protocol in the home automation market, with a forecasted 3.8 billion chips produced by 2023.
While this market share may soon be under threat, with the evolution of Matter, I don't think Zigbee is going anywhere. It is currently one of the best choices of smart home protocols with over 4,000 certified Zigbee devices available.
There are also constant improvements to the standard, such as the recent release of Zigbee Direct which incorporates Bluetooth Low Energy for device onboarding and control.
Large swathes of this website are dedicated to Zigbee devices so in this article, I’ll give you a full rundown of what the technology is and how it works.
What Is Zigbee?
Zigbee is a wireless communication technology that is commonly used in Internet of Things (IoT) and smart home devices. It is a complete system with its own application layer and network layer.
The protocol is ideal for low-power, low-data-rate devices and operates on the 2.4 GHz frequency band. It also uses mesh networking to allow devices to communicate with each other.
How Does Zigbee Work?
Zigbee works by creating a mesh network of interconnected devices, enabling low-power and short-range wireless communication among them. Each device in the network, also known as a node, can act as a sender, receiver, or repeater, which helps to increase the overall coverage and reliability of the network.
When a device wants to send data to another device within the network, it can transmit the data directly if it is within range or relies on other devices to relay the information until it reaches the destination device.
This mesh topology enables the network to self-heal and adapts to changing conditions, making it more resilient to interference and device failures.
Advantages and Disadvantages of Zigbee as a Smart Home Protocol
Zigbee has a number of advantages and disadvantages compared to other smart home protocols like Z-Wave, Wi-Fi, and Thread.
Advantages of Zigbee
- Low power consumption: Zigbee's low power requirements make it ideal for battery-operated devices, allowing them to last longer between charges or battery replacements.
- Mesh networking: Zigbee's mesh networking capability enables devices to relay data through other devices in the network, increasing overall coverage and reliability. This also allows the network to self-heal and adapt to changing conditions.
- Scalability: Zigbee networks can accommodate a large number of devices, making them suitable for applications ranging from small home automation systems to large-scale industrial monitoring and control.
- Interoperability: The Connectivity Standards Alliance, which oversees the development of the Zigbee standard, ensures that products from different manufacturers can work together seamlessly, making it easier for consumers to build and expand their smart home or automation systems.
- Cost-effective: Zigbee devices tend to be more affordable compared to other wireless communication technologies, making them an attractive option for budget-conscious consumers and businesses.
- Security: Zigbee incorporates a security framework that provides protection against eavesdropping and unauthorized access, ensuring the safe transmission of data across the network.
Disadvantages of Zigbee
- Limited data rate: Zigbee's low data rate, typically around 250 kbps, makes it unsuitable for applications that require high-bandwidth data transmissions, such as video streaming. So you won’t find many Zigbee cameras for example.
- Short range: Zigbee devices have a relatively short communication range, usually around 10-100 meters, depending on factors like environmental conditions and device power output. While mesh networking can help extend the overall network coverage, it may not be suitable for all applications or environments.
- Network latency: Due to the multi-hop nature of Zigbee's mesh networking, data transmission may experience latency as it is relayed through multiple devices before reaching its destination. This could be an issue in time-sensitive applications.
- Compatibility: While Zigbee is designed for interoperability, not all Zigbee devices are compatible with every Zigbee-enabled product or system. Consumers must ensure that the devices they purchase are compatible with their existing Zigbee network.
- Potential for interference: Zigbee primarily operates in the 2.4 GHz frequency band, which is shared by other wireless technologies like Wi-Fi and Bluetooth. This can lead to potential interference issues, affecting the performance of the Zigbee network.
What is a Zigbee Hub / Gateway?
A Zigbee hub, also known as a gateway, is a central device that connects and manages Zigbee-enabled devices within a smart home or automation system. It plays a crucial role in forming the network, assigning unique addresses to each device, and controlling the overall network operation.
It serves as the primary point of communication between the Zigbee network and other networks or systems, such as a Wi-Fi network or a user's smartphone.
The hub facilitates the transmission of commands and data between the Zigbee devices and the user's control interface, which can be a mobile app, a web interface, or a voice assistant.
In addition to controlling and managing Zigbee devices, the hub can also support various automation scenarios, such as creating routines, and schedules, or triggering actions based on specific events or conditions.
Some Zigbee hubs, like SmartThings or Hubitat, are designed to be compatible with multiple communication protocols, allowing them to integrate Zigbee devices with devices that use other technologies, such as Wi-Fi, Bluetooth, or Z-Wave, providing users with a more versatile and unified smart home experience.
Types of Zigbee Devices within a Network
Zigbee devices can be categorized into different types based on their roles and functionalities within the network. The primary types of Zigbee devices are below.
If you are interested in examples of Zigbee devices, then check out my article here.
The coordinator is a critical component of a Zigbee network, responsible for initiating and managing the network. There is only one coordinator per network, and it assigns unique addresses to each device, maintains routing tables, and controls overall network operation. Typically, a Zigbee hub or gateway acts as the coordinator in a Zigbee network.
As there can only be one coordinator in a network, it is a potential single point of failure (Unlike Thread which can share the “Leader” role among routers).
Routers are Zigbee devices that can relay data between other devices in the network. They have the ability to extend the range of the network by acting as intermediaries between devices that are not within direct communication range of each other.
Routers can also directly connect and control end devices. Common examples of Zigbee routers include smart plugs, smart switches, and some smart lighting products.
Routers are generally AC or DC powered.
End devices can send and receive data but do not have the capability to route data for other devices.
End devices typically have lower power requirements and often operate on batteries.
Examples of end devices include sensors (motion, temperature, humidity, etc.), smart door locks, and smart buttons.
Sleepy end devices
Sleepy end devices are a subset of end devices that spend most of their time in a low-power sleep mode to conserve energy.
They periodically wake up to communicate with the network, typically when they need to transmit data or check for updates.
Sleepy end devices are commonly found in battery-powered devices where power conservation is essential, such as wireless door and window sensors or smoke detectors.
These types of Zigbee devices work together within a mesh network to enable seamless communication and control of various smart devices.
What Is Zigbee 3.0?
Zigbee 3.0 is an enhanced version of the Zigbee wireless communication protocol, designed to unify and improve upon the various Zigbee profiles that existed in previous iterations.
This reduces fragmentation within the Zigbee ecosystem and ensures better compatibility among devices from different manufacturers.
Zigbee 3.0 strengthens security measures to protect against potential cyber threats, offering an upgraded security framework with features like secure boot, “touchlink” commissioning, and default support for encryption.
It also offers improved network management capabilities, making it easier for devices to join networks, maintain connectivity, and recover from network failures.
What is Zigbee Direct?
Zigbee Direct adds Bluetooth Low Energy (BLE) to the specification, allowing your phone to directly connect to a specific device and then negotiate a connection to the rest of the Zigbee network. This makes the setup process similar to Matter, providing more options for controlling devices without connecting to a dedicated hub.
How this would work
- A Zigbee device with Zigbee Direct (and therefore BLE) is added to the network.
- Your smartphone, with BLE support, connects directly to the Zigbee device (as opposed to a Zigbee hub).
- The smartphone negotiates a connection with the rest of the Zigbee mesh network.
- From this point on, the smartphone can control any device on the Zigbee network.
This could enable a more seamless transition to the Matter standard, potentially saving users thousands of dollars in unnecessary upgrades.
Brian from “Automate your Life” has a great video on how this could impact your smart home. Check it out below!
Are All Zigbee Devices Repeaters?
Not all Zigbee devices are repeaters. In a Zigbee network, as discussed above, only coordinators and routers act as repeaters.
These devices have the capability to extend the range of the network by routing data between other devices that are not within direct communication range of each other.
On the other hand, end devices and sleepy end devices do not function as repeaters, as they are designed primarily for data transmission and power conservation rather than routing data for other devices in the network.
How Secure Is Zigbee?
Zigbee incorporates a robust security framework to ensure the safe transmission of data across the network.
It employs features such as AES-128 encryption, secure key establishment, and frame counter-based replay protection to safeguard against eavesdropping, unauthorized access, and other potential cyber threats.
Unlike Thread which has mandatory commissioning, Zigbee has an optional commissioning process. So if a manufacturer opted for a simpler, less secure commissioning method, it could potentially expose the network to security risks.
That being said, Zigbee is generally considered more secure than Z-Wave, but less so then Thread. As with all networks, it is essential to follow best practices, such as regularly updating firmware and using strong, unique passwords.
What Frequencies Does Zigbee Operate On?
Zigbee operates in the 2.4 GHz frequency band, which is a globally recognized and license-free band for short-range wireless communication.
Additionally, Zigbee can also operate on lower frequency bands such as 915 MHz in North America and 868 MHz in Europe, though these lower frequencies are less common and have some regional restrictions.
Also, a network can only operate on one frequency band so you can not mix a 2.4GHz device with a 868MHz one.
What is the Range of Zigbee?
The transmission range of Zigbee devices typically varies between 10-100 meters, depending on factors such as the device's power output, environmental conditions, and potential obstacles.
However, the mesh networking capability of Zigbee allows data to be relayed much further, through multiple devices. By strategically placing Zigbee routers or repeaters throughout the network, the range and reliability of the Zigbee network can be significantly improved.
Also, the regional frequencies do offer a greater transmission range as lower frequencies generally have better penetration capabilities and can transmit signals over longer distances compared to higher frequencies.
It is important to note that the mesh networking capability of Zigbee can effectively extend the overall network coverage beyond the direct communication range of individual devices, regardless of the frequency being used.
How Do I Extend My Zigbee Network?
To extend a Zigbee network, you can add Zigbee routers or repeaters, such as smart plugs or smart switches, to the network. These devices help to increase the overall coverage by relaying data between other devices in the network, allowing communication between devices that are not within direct range of each other.
Placing routers strategically throughout the network can significantly improve its range and reliability.
Are Zigbee Routers and Repeaters the Same Thing?
Within the context of a Zigbee network, routers, and repeaters are essentially the same, both serving to extend the network's coverage and relay data between devices.
You’ll often find the terms “router” and “repeater” are often used interchangeably when discussing Zigbee.
It’s important to note that unlike a Wi-Fi repeater, which only serves the purpose of amplifying and retransmits signals, a Z-Wave router/repeater is actually a part of the mesh network and also serves its own purpose. (Such as a Zigbee light switch or a Zigbee smart plug)
How Does Zigbee work with Matter?
Matter, is an open-source, royalty-free standard for smart home devices developed by industry leaders like Apple, Google, Amazon, and the Connectivity Standards Alliance (CSA) (Formerly the Zigbee Alliance)
Matter aims to improve interoperability among smart home devices across different ecosystems.
There are two ways Zigbee devices can work with Matter. The first is by pushing a firmware update to devices so they also implement the Matter protocol. The second is by utilizing a bridge between the Zigbee network and Wi-Fi and Thread networks.
If you're interested in Zigbee, check out our other related articles.