Why Matter matters, and how does WiFi and Thread fit into it.

<Updated 23rd Oct 2023>

This is, mostly, a technical post.... and it differs from most of my posts because the new Matter standard had only just been released when I initially wrote it and there's not much out there as devices go.... so I have little practical experience.

So, why am I writing this? Well, because there seems to be a great deal of confusion about what Thread is, what Matter is, and how HomeKit integrates with them.

I must admit, to pull this together, I have had to draw from many sources.

A few words of warning. 

Follow the old adage, "If it ain't broke, don't fix it." It's not necessarily an "upgrade" to Matter. If you have a device that works perfectly well in HomeKit and you do not need the multi-controller capability, keep it in HomeKit. An example would be lights that support adaptive lighting. It's not supported in Matter yet, so if you use that capability and you change to Matter support you will lose that capability in HomeKit.

History of Matter

I thought this would be a good place to start. Most of this is factual, some is conjecture which, I hope, will be obvious as I write this.

In 2019 Amazon, Apple and Google came together, under the auspices of the Zigbee Alliance now renamed to the Connectivity Standards Alliance, and created Project Connected Home over IP - or Project CHIP.

What were the driving forces behind this? Why did these 3 companies come together?

One of those things is that there needed to be a single way for devices to be certified. There are many different standards out there, and there are many different eco-systems, although the dominant 3 are those very 3 that formed this project. Quickly, others joined in though, such as Comcast, Samsung SmartThings and Tuya. There are now over 400 companies involved in Matter and more joining all the time.

The problem with all those different eco-systems is that it is confusing for customers. You, essentially, have to pick an eco-system and stay with it if you want to get any form of reasonable capability. It is amazing how many people do not do that, and then the confusion that it causes.... as well as they then feel like they wasted their money as they can't get all the benefits they were promised.

Another is retailers. They often had to deal with products being returned because of the above customer issues. They also had to, at times, store different versions of the same product to match the different eco-systems.

Developers had to build products with multiple eco-systems in mind, and had to get that product certified multiple times, driving up cost and, often, limited support beyond the big 2 (As much as I like Apple's HomeKit, it's been running a poor 3rd to the other 2).

So, why did the eco-system big 3 start this?

I think Amazon and Google wanted the local control and security that Apple has. We've seen what happens when sections of the cloud go down, or even if you just lost your internet connection.... nothing works. Even when the internet was up, the delay caused by going out to the cloud and back again sucked for Automations (Using a voice assistant to turn on a light is not an automation). Apple's HomeKit would continue to work, except for Siri... but that was partly rectified in iOS 15...... and automations were local. Amazon has, in particular, been hammered around its security and how it handles personal information, not helped by Alexa just advertising stuff.

What does Apple get then? 

1. Well they are running a poor 3rd mainly because of certification of products. Many many times I have heard about how difficult Apple is to work with. However, certain companies seem to do it well, so I'm not quite sure where the responsibility lies. Still, the reality is that Apple HomeKit does not support that many products, especially when compared to Amazon and Google. Also, it is lacking in certain product categories, supported by the other 2. 
2. Apple will, eventually, get an expanded accessory support from Matter. Unlike Google and Amazon, Apple has shown no interest in creating Home Automation products, except controllers, such as the HomePod and the tv. Therefore, I think this is an acceptance of what they do badly, certification, and the CSA has shown that it can do that very well.... just look at how many certified Zigbee devices are out there!
3. Expanded device types. Again, this has been slow in HomeKit, and we've not seen many new device types over the last 12 months. Where are robot vacuum cleaners for example? However, we do not see anything new in V1.1 of the Matter spec as, so far, the device types are all already in Homekit. V1.2 does, though add new device types, but some functionality is still missing:
• Light (On/Off,  Dimmable, Extended)
• Plugs/Outlets
• Switch
• Door Lock (extended in V1.2)
• Speaker (On/Off, Volume)
• Thermostat
• Window Covering
• Garage Doors
• Wireless Access Points & Bridges
• Televisions and Streaming players
• Temperature sensor
• Humidity sensor
• Illuminance Sensor
• Occupancy sensor
• Contact sensor
• Motion sensor
• Smoke and CO sensors (Expanded in V1.2): Support for notifications, audio and visual alarm signaling, alerts about battery status, end-of-life notifications, and self-testing. Carbon monoxide alarms support concentration sensing.
• Air Quality Sensors (V1.2): Supported sensors can capture and report on PM1, PM 2.5, PM 10, CO2, NO2, VOC, CO, ozone, radon, and formaldehyde. Matter devices can also provide AQI information based on location.
• Air Purifiers (V1.2): Can pair with an air quality sensor for sensing data and uses functionality from other device types like fans and thermostats. Monitoring of things like filters (HEPA and activated carbon filters) is also supported.
• Refrigerators (V1.2): Includes deep freezers, wine and kimchi fridges. Functions include temperature control and monitoring
• Washing machines (V1.2): Progress notifications, such as cycle completion. The CSA says dryers will be supported in a future Matter release.
• Dishwashers (V1.2): Functions include remote start and progress notifications, plus notifications for water supply and drain, temperature, and door lock errors.
• Robot Vacuum cleaners (V1.2): Functions like remote start and progress notifications, support for features like cleaning modes (dry vacuum and wet mopping), and status details such as brush and charging status and error reporting.
• Room air conditioners (V1.2): 

Standalone room air conditioners with temperature and fan mode control.

Fans (V1.2): 

Movement controls like rock / oscillation and modes like “natural wind” and “sleep wind” will be supported, plus changing the airflow direction (forward and reverse) and step commands for airflow speed. 

In May 2021, CHIP became Matter and ratified the first beta version of its specification. There are some really cool things in there, but also some interesting omissions, such as Cameras. V1.0 of the spec was released in October 2022, V1.1 was released in May of 2023 and V1.2 was released 23rd October 2023, in keeping with their aim of 2 releases a year.

It should be noted that when a version of the standard is released, it doesn't mean that any of the controllers (Apple Home, Smartthings, Alexa, Google Home, etc) will support those new standards immediately. It will take time. Then, obviously, the manufacturers need to build 1.2 capability into their products.

What does Matter do?

It provides the promise of a standard method to build IoT (Internet of Things) devices and is aimed squarely at the smart home/building. This will mean that:

1. Developers build once to a standard
2. Products are certified once
3. Retailers only have to stock one version of a product
4. Customers will not have to care about the eco-system, it will work with any eco-system that supports Matter.
5. Developers can still add in unique capabilities that are not covered by Matter and so still show uniqueness.... if they want.

V1.0 of the spec did not support everything, but it does support many things. It is the intention that the spec is continually evolving and expanding as shown in the 1.2 spec.

There are not a huge number of Matter products yet, but the list is building. Not too surprisingly, many of the early adopters are companies that have traditionally been in the Apple HomeKit ecosystem, such as Eve and Nanoleaf but we are now seeing integrations with company's like SwitchBot who have Matter integration in public Beta.

Watching a CSA video, they said there were 30 "early adopter" companies expected to get product out of the door by the end of 2021. More recently, CSA has been talking about over 400 products being available by the end of 2022. In many cases these are just software updates. Signify (Philips Hue & Wiz) have stated that Hue will get a software update to the bridge, but still talk Zigbee to its bulbs. With regard to Wiz, they have talked about hardware upgrades needed so that will probably be 2022. Google has announced support for Matter as has Apple during its WWDC 2021, and even going into detail on how it will be integrated into HomeKit, they went further in 2022. Finally, in July 2021,Amazon announced what it will do with it's Echo devices but gave no time frame, but did a massive update in 2022 on its plans and has started rolling out in 2023. Amazon also stated that some of its brands, like Eero, will decide for themselves if they wish to support Matter or not. However, as of December 2021 Amazon has given much more detail and has a pre-production SDK for Matter. SmartThings has embraced Matter support and they, potentially, could be an interesting integration point as they already support Z-Wave and Zigbee, so could be used to bridge into other standards. However, they have stated that they will not be a passthrough device.

How does Matter work?

To start off with, there is a need to understand networking stacks. There are a number of levels, but essentially there are 3 levels that you need to care about. Broadly, there are:

1. Application Layer
2. Networking Level, e.g. TCP/IP V6
3. The Physical level, e.g. Ethernet, WiFi, Thread, etc.

Matter sits at the Application layer. This is the same layer where HomeKit, Amazon Alexa and Google Home all sit. 

Matter, as a requirement, uses TCP on IPv6 and, in the V1 spec, that can run on top of Ethernet, WiFi and/or Thread... and this is where Thread comes in. Thread runs on the same radio used by Zigbee, but uses IPv6 rather than its own networking protocol and does not go into the application layer, like Zigbee does.

Matter also uses BLE (Bluetooth Low Energy), but only for configuration.

Initially, there were some questions about Matter working over Ethernet in V1. All Matter news communications have talked about the ability to go beyond WiFi & Thread, but not in the V1 spec. However, Philips Hue (Signify) had stated that their bridge would become Matter certified, and that uses an Ethernet connection to the outside world, and Zigbee V3 to its own ecosystem. As of Jan 2022, the CSA released a news article that included Ethernet and Philips Hue has finally delivered the firmware update that enables Matter support.

Beyond V1, it is expected to add more physical layers.

Matter also has a data model, This defines what devices, equivalent to HK accessories, can do. There is a fair amount of detail about this in a WWDC presentation on integration Matter with HomeKit.

However, essentially Matter will take over a number of the functions currently being done by HomeKit. Interestingly, Matter does not seem to go into Automation, just connectivity.

Extending HomeKit using Matter

Matter introduces the concept of Controllers. You can have a single Controller or multiple ones. A Single Controller could be a HomeKit Controller, such as an tv or a HomePod. Multiples could be HomeKit Smartthings and Alexa, if you were so inclined.

These Controllers are where Automation comes in. With regard to the Apple Ecosystem, this would be in the HomeKit Framework.

On top of the HomeKit Framework is then the various UI's such as Siri, the Apple Home App, Home+, HomeKit Controller, etc.

What's also new is the concept of Controllers are not limited to a "Home" but actually on an individual device. If you think about this, it means that you can now provide control for a "Room" for guests, or your children. Maybe you're running an AirBnB. This also extends into what Matter calls Multi-Dwelling homes, and is covered in this video, although I've yet to see any implementation of this.

Matter has also brought new types of accessories as it has extended beyond its V1.0 Specification.

It also seems from the Apple presentation at WWDC, linked above, that there will not be a double requirement for certification. They clearly state that the object is single certification so if it is certified on Matter, it will work with HomeKit. I believe that this will mean that HomeKit certification will be phased out.

However, there are certain capabilities, such as adaptive Lighting, which are not in the Matter standard, but is in HomeKit. Therefore it will still need to connect via HomeKit rather than Matter (Think Hue or Nanoleaf) and will still need HomeKit certification.

Thread and Matter

Recently in HomeKit we've been seeing a number of Thread devices. Thread is just another transport for HomeKit at this point and, to use it in HomeKit, you need an tv 4K (V2 or V3), a HomePod mini or a 2nd gen HomePod. All of these act as a Thread Border Router, which essentially translates from your normal network to the Thread IPv6 network.... but really it's just replacing any other Transport, such as BLE or WiFi. 

Interestingly, Nanoleaf have released an update for some of their controllers so that they can now act as a Border Router. Nanoleaf have also advertised that they will be releasing an update to their firmware, on Shapes and Lines, so they can act as a Border Router for HomeKit. This means that older models of HomePods and tv's do not need to be upgraded.

However, as Thread is part of the Matter standard, as is WiFi, it should be possible to deliver a software update that will enable Matter support at a later date. This has been announced by Nanoleaf and Eve, for example. Although Nanoleaf have now stated that not all of their existing products can be upgraded to Matter due to the extra hardware requirements. Eve have definitely followed through with this.

Thread 1.3.0 was released which made it ready for Matter and meant that we should be able to move away from specific versions of Thread, such as implemented for HomeKit.

You do have to be careful with Thread though. You really need to be consistent with where it is set up. if you are going to do a multi-platform set up, always do it from an iOS device otherwise you may end up with islands of Thread that do not talk to each other.

What's so special about Thread?

Well, basically it is low powered, it's quick and it creates a mesh. This means it can be used in battery powered devices, you have redundancy in the network, and it's quicker than BLE.

Within Thread you have end points. End Points are devices that you wish to control. They can be anything, but something that is soley and end point tends to be battery powered and is something like a door/window sensor. So, you get the benefits of BLE, but you get much faster speed of response.

The next layer up is called a Router. These create the mesh that the end points connect to. There is a maximum of 64 in any Thread mesh. If there are more than 64 Routers, the rest become Router Enabled End Points and when a Router drops out, one of those Router Enabled End Points is promoted to a router.

Just to confuse things, a Router is also a device you wish to control.

As mentioned before, there is also a border router that passes information into the Thread Mesh. If you have multiple Border Routers, that's just fine. It gives you redundancy.

There is also a master router that controls all of the routers. This is not necessarily the same as the border router.

Anything that is a router is usually powered as it consumes power to deliver the functions. So, Eve Energy or Nanoleaf lights are Thread Routers. Eve Door and Window sensors are end points.

Why Thread rather than Zigbee?

It's an interesting question. They are very similar, but do have some slight differences in how they run the mesh. Zigbee is very centralised and the mesh controller is usually the Zigbee hub. It is a single point of failure. Thread distributes the load around more, and the controller is self elected. This means that if the controller fails, another is appointed. The potential for failure is only if you have a single border router. 

Having said that, essentially because Thread uses IPv6. This means that it reduces complication for the developers. Zigbee is great for low power and low bandwidth, but it is not any good for high bandwidth devices. This means that any developer with both kinds of devices would have to integrate with those 2 layers, one being TCP/IP and the other being Zigbee. With Matter adopting Thread, developers only have to develop to Matter, and Matter will communicate over TCP/IP over WiFi and Thread and, later, other physical layers.

Why Matter rather than Z-Wave

Well, Z-Wave has a huge eco-system, and so will be around for a long time I suspect. It has been a very good solution for low band-width devices and is very stable as it isn't in a crowded radio frequency spectrum. However, it is essentially proprietary, which Matter is not, and I believe it will slowly wither away as Matter picks up speed and market acceptance. For HomeKit users, Z-wave has been, mostly, irrelevant as it is only recently that a bridge has become available. However, for anyone else I'm not advocating not buying z-wave devices if you want that functionality now, as it will be bridged, I think, by at least SmartThings.

WiFi and Matter

Similar to Thread, a software update should also be possible as WiFi is also part of the Matter specification. This sort of update has been announced by Signify for Philips Hue, all be it that their announcement is confusing as they use Ethernet.

Conclusion.

This is a major step forward. Beyond the original 3 amigo's, it is also interesting to see Comcast, SmartThings and Tuya being involved.

This really does seem to be the way forward for IoT. It'll take a while for devices to come out, and the standard will keep evolving and adding new types of devices, such as Cameras.

Meanwhile, HomeKit will continue to work with existing HK accessories, but also with new Matter devices. We are being told that this will be in a seamless manner.

Looking good to me though.