Protocols > Thread
Application Scenario
Thread is specifically designed for low-power smart home devices such as lighting, thermostats, and door locks. Its mesh network features self-healing capabilities for faulty nodes, ensuring stable and reliable connectivity.
Thread is suitable for large commercial building automation scenarios, such as lighting, HVAC, security, and asset tracking. Its excellent scalability and reliability support stable communication for massive numbers of devices.
Thread achieves secure connection of devices to the internet and cloud through a Border Router, supporting functions like remote monitoring and firmware updates. Thread versions 1.3.0 and 1.4 have standardized the Border Router design, further simplifying the integration process with IP infrastructure.
Thread is based on the IPv6 protocol and is seamlessly compatible with existing IP networks such as Wi-Fi and Ethernet. The Border Router provides bidirectional IPv6 connectivity, supporting cross-network device interoperability, such as the interconnection between Matter devices connected over Wi-Fi and those over Thread in a home environment.
As a network layer protocol, Thread supports multiple application layer protocols (such as Matter, KNX IoT, DALI+) to run concurrently on a single network, effectively enhancing the interoperability of devices from different vendors.
Thread is specifically designed for low-power smart home devices such as lighting, thermostats, and door locks. Its mesh network features self-healing capabilities for faulty nodes, ensuring stable and reliable connectivity.
Thread is suitable for large commercial building automation scenarios, such as lighting, HVAC, security, and asset tracking. Its excellent scalability and reliability support stable communication for massive numbers of devices.
Thread achieves secure connection of devices to the internet and cloud through a Border Router, supporting functions like remote monitoring and firmware updates. Thread versions 1.3.0 and 1.4 have standardized the Border Router design, further simplifying the integration process with IP infrastructure.
Thread is based on the IPv6 protocol and is seamlessly compatible with existing IP networks such as Wi-Fi and Ethernet. The Border Router provides bidirectional IPv6 connectivity, supporting cross-network device interoperability, such as the interconnection between Matter devices connected over Wi-Fi and those over Thread in a home environment.
As a network layer protocol, Thread supports multiple application layer protocols (such as Matter, KNX IoT, DALI+) to run concurrently on a single network, effectively enhancing the interoperability of devices from different vendors.
Basic Working Principle
The Thread protocol constructs a low-power IPv6 network based on the IEEE 802.15.4 standard. It uses a 6LoWPAN adaptation layer to compress IPv6 headers, thereby reducing transmission overhead, and performs fragmentation and reassembly when data packets exceed the maximum transmission unit (MTU) of the MAC layer. Simultaneously, it employs a Mesh Header at the link layer to achieve multi-hop data forwarding, reducing the load on the network layer, while the combination of IP routing and 6LoWPAN link-layer forwarding enhances transmission efficiency. Network devices support automatic IPv6 address configuration and transmit data through routing protocols. In terms of security mechanisms, Thread uses a network-wide key to protect data frames at the MAC layer, and employs the DTLS protocol to ensure the safety of the commissioning process. New devices require authorized configuration and are centrally managed by a Commissioner for joining the network and parameter transmission.
The Thread network comprises two roles: Routers and End Devices. Routers act as the backbone of the network and maintain an always-on state, responsible for routing data packets. The Thread network can support a maximum of 32 active routers to form a mesh topology, providing redundancy and self-healing capabilities. Routers optimize message forwarding by maintaining a routing table.
End Devices rely on a parent router for communication and can be classified into Router-Eligible End Devices (REEDs) and Sleepy End Devices (SEDs). REEDs have the capability to upgrade to a router, while SEDs are low-power devices that remain active only when necessary and do not participate in network routing.
Thread network devices are classified into Full Thread Device (FTD) and Minimal Thread Device (MTD). An FTD can function as a Router, a Router-Eligible End Device (REED), or a Full End Device (FED), and maintains links with neighboring routers. In contrast, an MTD has lower hardware requirements and power consumption, operating as an End Device (ED) that communicates through a parent router and wakes periodically to synchronize. End devices are classified into three types: Sleepy End Devices (SED), Synchronized Sleepy End Devices (SSED), and Wake-up End Devices (WED). The SSED utilizes the Coordinated Sampled Listening (CSL) mode for data reception, achieving higher energy efficiency by precisely managing its sleep-wake cycles. WED (Wake-up End Device) is a type of device that offers a time-slotted synchronous transmission mode. Its core characteristic is the ability to be directly awakened for a connection by a Wake-up Coordinator (WC), such as a smartphone, even in the absence of an existing Thread network. After the control operation is complete, the WED can quickly return to a lower-power, wake-up listening state. This mechanism not only provides WED with advantages like low power consumption, high flexibility, and strong adaptability, but also enables better support for multi-protocol coexistence.
A Border Router is responsible for interconnecting Thread network nodes with external IP networks (Internet/LAN/VPN) and forwarding data. Since it is based on the same IPv6 protocol eliminates the need for protocol translation, thereby simplifying communication processes.
A Thread network can also support multiple active Border Routers to provide redundancy and resilience, avoiding single points of failure. Additionally, Border Routers may additionally offer application-layer services (e.g., Thread device discovery proxies). During commissioning, when the Commissioner resides on an external network, the Border Router acts as a secure intermediary to assist device access. Simultaneously, Border Routers can participate in external routing protocols, announcing global IPv6 prefixes and assigning addresses to each node.
Thread network implementations are categorized into three hardware architectures:
System-on-Chip (SoC): Integrates radio frequency (RF), processor, and protocol stack into a single chip. Controllable directly via Thread APIs, it features low power consumption, cost-effectiveness, and multi-protocol coexistence (e.g., Wi-Fi/Bluetooth). Suitable for end devices like sensors.
Radio Co-Processor (RCP): Deploys the protocol stack on the host processor while retaining MAC layer control on the RF module. Communication occurs via SPI/UART interfaces using the Spinel protocol. The host processor runs continuously to ensure reliability, adapting to high-computing power devices like video hubs.
Network Co-Processor (NCP): Runs the full OpenThread protocol stack on a co-processor. The host processor sends commands via UART/SPI and can enter sleep mode, while the co-processor maintains network connectivity. Suitable for multitasking devices such as gateways or IP cameras.
Specification Parameters
- Compliance with the IEEE 802.15.4-2015 specification
- Hardware CSMA-CA mechanism, automatic ACK response, and FCS check
- Support for all CCA modes (ED/CS/Combined Mode) and reports per packet RSSI/LQI report
- Hardware AES-CCM security engine
- Coexistence mechanism for multi-protocol PHY layers
- Fully support Zigbee Pro and Zigbee 3.0 protocols
- Fully support for the latest Thread protocol (Thread 1.4)
- Supports other protocols based on IEEE 802.15.4, e.g., RF4CE
Advantages
Supports concurrent operation of Thread (or Zigbee) and BLE protocols on a single chip.
Providing a complete solution for smart home IoT featuring low power consumption, low latency, and high performance.
The single chip is equipped with rich peripheral interfaces and provides comprehensive application examples to accelerate the IoT product development process.
Product Applications
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