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What is a Protocol?
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What do we mean by a protocol? In networking terms, a protocol is a predetermined set of rules and standards between devices. Its how your smart home appliances are reaching out and speaking to each other. This can include the spectrum, language, ports, and appropriate responses. A device can use multiple protocols, but certain actions may need a specific protocol. You need to confirm compatibility between your devices, especially your controllers. For example, the controller in an Amazon Echo Plus only works with Zigbee devices.
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WiFi:
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You are probably most familiar with WiFi. It was formalized by the Institute of Electrical and Electronics Engineers, an international non-profit organization for electrical standards. Formally known as IEEE 802.11, it comes in a few different flavors, but all work the same for our purposes here. Most modern WiFi networks work on both the 2.4 GHz and 5 GHz spectrum. It has a range of about 25 meters between devices, if you aren’t using any devices to extend the signal. In a standard WiFi network, every device on the network communicates with each other and can see the traffic.
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Pros:
Because of the high bandwidth in the two spectrum it can use, WiFi tends to be the fastest point to point between devices.If you have a WiFi router, you can use WiFi devices. It is the most compatible of the standards here.Because of the compatibility and the large market share, WiFi is also the most easily scalable. WiFi devices also tend to be the most affordable, since the technology is so readily accessible to manufacturers.WiFi devices, especially on the 5 GHz spectrum, can send the greatest amount of data. This works especially well if you are trying to stream high-quality video.WiFi devices also tend to be the easiest to implement. Just add them to your WiFi network and log into your account for the relevant service.
Cons:
WiFi devices have a powerful radio and do more processing at the device itself, which requires greater energy consumption.Even though accessing the higher spectrum gives them more bandwidth, having too many devices can cause congestion and slowness.The higher bandwidth comes with shorter range as well, unless you purchase a separate device to extend the range.WiFi also has quality control issues. Because the technology is so cheap and readily available, there is a very low bar for implementing it into devices. Some manufacturers just throw it in as an afterthought or simply just try to get “smart devices” with WiFi on the market as fast as they can to cash in on the trend. There is no organization watching over the implementation of WiFi like there are for the other standards.All of those cheap devices also raise security concerns. In my post about home network vulnerabilities, I outlined how smart home devices on WiFi can be used to access your network.WiFi devices also tend to require registration on some cloud service. Not only does this expand on the previously mentioned security concern, having to reach out to a cloud server over the internet also adds lag to your device.
Z-Wave:
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Z-Wave was created by the Z-Wave Alliance, a group of technology companies led by Silicon Labs. It works on
the 900MHz spectrum, which is the same as older cordless phones. This lower spectrum actually provides for a longer range per device at 100m. Z-Wave devices also form a mesh, which means each device actually extends the signal. Z-Wave is somewhat open, but the Z-Wave Alliance still maintains strict control over how it implemented. This provides a quality control mechanism but also increases cost. Recently, the Z-Wave Alliance has been opening up more of the Z-Wave protocol to increase adoption and decrease the cost of implementation. The protocols have also been revamped several times over the years.
Pros:
At 100 meters, Z-Wave has the longest range of any of the protocols discussed here.Because it works on a lower spectrum, Z-Wave devices require less power.The mesh capability works to increase the range even more.Because so few devices within the home still use the 900 MHz, Z-Wave devices are less likely to suffer interference.The Z-Wave Alliance makes sure the protocol is updated to keep up with changing technology.The Z-Wave Alliance also maintains strict quality standards for implementation.Ideal for small, simple devices like door sensors.
Cons:
Because of the standards enforced by the Z-Wave Alliance, Z-Wave is more expensive to implement.The upgrading of the protocol also leads to compatibility problems with older Z-Wave devices Because Z-Wave is on the 900 MHz spectrum in the US, it may not work if you take a device to another country. 900 MHz tends to be heavily regulated because it is a common radio frequency.Because it is on the lower-powered spectrum, Z-Wave networks are limited to 230 devices at once, the fewest of any of the protocols on this list.A hub is required to connect a Z-Wave device.
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Zigbee:
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Zigbee is another protocol from the IEEE, designate IEEE 802.15.4. It also works on the 2.4 GHz spectrum like older WiFi devices. Zigbee enabled devices typically have a range of 10 to 20 meters but are also capable of making a mesh network. There is practically no limit to the number of Zigbee devices you can have on a network. Zigbee devices can be found in many settings like medical offices, but the best known smart home manufacturer that utilizes Zigbee if probably Philips in the Hue product line.
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Pros:
Zigbee devices tend to be less expensive than Z-Wave.Like Z-Wave, Zigbee devices can form a mesh network to extend their range.Good for devices that need short-range, secure communication because it can use encryption. Zigbee has always been pretty much the same despite some revisions, so there are no compatibility issues in that regard.There is no real limit on the number of devices a single Zigbee network can have.
Cons:
Despite it technically being an open standard, some manufacturers manage to close off their Zigbee devices. This creates a type of “Walled Garden”.Zigbee devices need that mesh capability, because each device has a maximum range of 20 meter Like Z-Wave, Zigbee devices require a hub to control Being on the 2.4 GHz spectrum can cause problems of congestion with WiFi devices.
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Bluetooth Low Energy:
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Pretty much what it says on the tin, Bluetooth Low Energy was developed by the Bluetooth Special Interest Group to allow the networking protocol to be utilized in small devices that need close-range communication. It works similarly to the regular Bluetooth you probably already know just with a shorter range and fewer data transferred. BLE maxes out at about 100 meters. It also works on the 2.4 GHz spectrum. Bluetooth devices can also be used in a mesh network
Pros:
You probably already have Bluetooth devices.It is relatively cheap to add to a device.Low energy consumption means fewer battery replacements.It has mesh networking capability.
Cons:
Because it is a newer standard, it is harder to find devices using it The lower bandwidth limits how much data Bluetooth Low Energy can transmit at one time.This also opens Bluetooth to security problems compared to standards like Zigbee and WiFi.
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Connected Home Over IP:
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Feeling a little overwhelmed? It does seem like a lot. And these are just the most common standards you will find. There are plenty of other older and less used standards. Fortunately, it looks like the major manufacturers have heard our frustration. It was recently announced that new standard is being developed with the combined efforts of companies like Amazon, Google, and Apple, as well as organizations like IEEE and the Z-Wave alliance. The new standard will be compatible with existing technology and also allow manufacturers to make devices that all devices can connect too without any intermediaries. It is currently referred to as Project Connected Home over IP.
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