The smart home devices hitting the markets use a variety of methods for communicating. Some use more common and known protocols such as WiFi and Bluetooth, while others use lesser known protcols such as Zigbee and Z-Wave. In general, devices using Zigbee or Z-Wave, rely on a hub or a bridge. The controlling application communicates with the bridge via wifi and the bridge uses the Zigbee or Z-Wave protocol to control the end device, such as a light.
Meshed networks allow each device to communicate directly with any other device within range. If two devices are too far apart, their signals can hop along intermediate devices. Devices can drop in and out of the network without affecting the network's overall strength.
ZigBee and Z-Wave are mesh networking technologies, and are the most widely used wireless standards in smart home devices today. They are however, not compatible with each other. Each individual device does not rely on, and works independently of your Wi-Fi network. Instead, they communicate amongst themselves.
ZigBee can support more than 64,000 devices on a single network while Z-Wave supports 232. In both cases, these limits are way more than what would be required in a home.
WeMo is a brand of Belkin, a maker of networking gear and accessories. WeMo relies on the Wi-Fi standard and so is dependent on a central router handling all the traffic among the WeMo devices, a "star" network topology vs a full mesh. Because WeMo devices send signals to each other via a Wi-Fi router, each WeMo device requires its own IP address which could impact network scaleability as the number of WiFi enabled devices increase on the network. Another drawback to Wi-Fi is its power consumption. As a general rule battery-operated smart-home devices are a bad choice for Wi-Fi.
Thread, announced in July 2014, is an emerging smart-home networking protocol developed with the goal of supporting the "Internet of Things" as it develops for the future. Thread natively handles IPv6 (does not use IPv4) and like ZigBee, is based on the 802.15.4 radio standard.
The protocol creates a self-healing low-power mesh network that can link more than 250 devices using the 2.4 GHz band. ZigBee and Thread share some basic underlying physical specifications and as a result could result in a degree of interoperability in the future.
Bluetooth Mesh, first announced in July 2017, builds on the Bluetooth Low Energy standard. It will allow devices to communicate with each other in much the same way that Zigbee and Z-Wave devices do. It has a much longer range, up to 300 feet.
|Operating range||100 feet||35 feet||100 feet||100 feet (theoretical)||330 feet|
|Max no. devices||232||65,000||Router-dependent||250-300||32,000|
|Data rate||9.6-100 kbps||40-250 kbps||Router-dependent||250 kbps||1 Mbps|
|Frequency||908/916 MHz||915 MHz/2.4 GHz||2.4 GHz||2.4 GHz||2.4 GHz|
Communication and speed
ZigBee and Z-Wave use different frequencies for communicating with smart devices. ZigBee operates on the 915Mhz band as well as the 2.4GHz band. Z-Wave, on the other hand, operates on the 908.4 MHz and 916 MHz bands. Z-Wave's data rates top out at 100kbps. ZigBee can reach up to ~250kbps when operating in the 2.4GHz frequency and at 40kbps when operating in the 915 MHz. This range uses less power consumption.
The speeds may sound extremely low, but is unlikley to be a factor in performance given the limited data being transmitted. It does not take a lot of bandwidth transmit on/off, dim/brighten or change color messages.
Range should be a major concern if the distribution of the devices are carefully planned. Thanks to their mesh networking capabilities, the more devices across the network the more the range can be increased.
ZigBee is an open protocol created and maintained by the ZigBee Alliance whereas the Z-Wave protocol is used under license from company Sigma Designs.
Products supporting both ZigBee and Z-Wave
ZigBee compatible products
Amazon Echo Plus has a built-in ZigBee hub, providing control of ZigBee certified products without having to buy a separate ZigBee hub.