In principle, any IPv6-bearing network is suitable for Matter deployment, subject to supporting a few core IPv6 standards. In the current version of the specification, we focus on three link layer technologies: Ethernet, Wi-Fi and Thread. We restrict the specification to the above so that the specification can suitably cover provisioning of these link layers, and so that the amount of testing in certification is suitably bounded.
Matter treats networks as shared resources: it makes no stipulation of exclusive network ownership or access. As a result, it is possible to overlay multiple Matter networks over the same set of constituent IP networks. This protocol may operate in the absence of globally routable IPv6 infrastructure. This requirement enables operation in a network disconnected or firewalled from the global Internet. It also enables deployment in situations where the Internet Service Provider either does not support IPv6 on consumer premises or where the support proves otherwise limiting, for example, if the delegated prefix cannot accommodate all the networks and devices on premises. This protocol supports local communications spanning one or more IPv6 subnets. Canonical networks supporting a fabric may include a Wi-Fi/Ethernet subnet, or one or more low power and lossy networks (LLN) subnets. In this version of the specification, Thread is the supported LLN standard. Matter uses IPv6 for its operational communications, and leverages both IPv6 Unicast and Multicast addressing for accessing its Nodes and Groups, respectively.
This is the simplest transport for Matter, as there is no need to communicate any network credentials to the device; it is simply connected to the Ethernet network. Commissioning of devices should use the on-network bitmask in the Discovery Capabilities of the Onboarding Payload and the device will be discovered via DNS-SD.
Matter devices may use the 802.11 (Wi-Fi) standard for connectivity, any of the approved versions of this spec are compatible with Matter and all the approved frequency bands may be used (subject to local regulatory limits). In order for a Matter device that uses Wi-Fi to be certified the manufacturer must first obtain Wi-Fi certification for the device from the Wi-Fi Alliance. This can often be obtained via the Wi-Fi chipset vendors existing certification. For commissioning, Wi-Fi devices may use the Bluetooth Low Energy (BLE) method of discovery and conveying of network credentials or the device may already be connected to the IP network via an existing proprietary method.
Thread is a low power 802.15.4 mesh-based radio protocol designed for IP transport. There are a number of additional considerations when using Thread for a Matter device which are explained on the dedicated Thread page of this site. In order for a device that uses Thread to be Matter certified, the manufacturer must first obtain Thread certification for the device from the Thread Group. When a device uses Thread, it must also use BLE for Discovery and Commissioning in order to provision the Thread network credentials to the device.
BLE is used in Matter as part of the discovery and commissioning stage as a method for passing the credentials of the Wi-Fi or Thread network that the device will use for operational communication. BLE is required where a device uses Thread and optional for Wi-Fi. BLE cannot be used as the sole transport technology for a Matter Device.