1.4 Thread General Characteristics
The Thread stack supports IPv6 addresses and provides low-cost bridging to other IP networks and is optimized for low-power / bat-
tery-backed operation, and wireless device-to-device communication. The Thread stack is designed specifically for Connected Home
and commercial applications where IP-based networking is desired and a variety of application layers can be used on the stack.
These are the general characteristics of the Thread stack:
• Simple network installation, start-up, and operation: The Thread stack supports several network topologies. Installation is simple
using a smartphone, tablet, or computer. Product installation codes are used to ensure only authorized devices can join the network.
The simple protocols for forming and joining networks allow systems to self-configure and fix routing problems as they occur.
• Secure: Devices do not join the network unless authorized and all communications are encrypted and secure. Security is provided
at the network layer and can be at the application layer. All Thread networks are encrypted using a smartphone-era authentication
scheme and Advanced Encryption Standard (AES) encryption. The security used in Thread networks is stronger than other wireless
standards the Thread Group has evaluated.
• Small and large home networks: Home networks vary from several to hundreds of devices. The networking layer is designed to
optimize the network operation based on the expected use.
• Large commercial networks: For larger commercial installations, a single Thread network is not sufficient to cover all the applica-
tion, system and network requirements. The Thread Domain model allows scalability for up to 10,000s of Thread devices in a single
deployment, using a combination of different connectivity technologies (Thread, Ethernet, Wi-fi, and so on).
• Bi-directional service discovery and connectivity: Multicast and broadcast are inefficient on wireless mesh networks. For off-
mesh communication, Thread provides a service registry where devices can register their presence and services, and clients can
use unicast queries to discover the registered services.
• Range: Typical devices provide sufficient range to cover a normal home. Readily available designs with power amplifiers extend the
range substantially. A distributed spread spectrum is used at the Physical Layer (PHY) to be more immune to interference. For com-
mercial installations, the Thread Domain model allows multiple Thread networks to communicate with each other over a backbone,
thus extending the range to cover many mesh subnets.
• No single point of failure: The Thread stack is designed to provide secure and reliable operations even with the failure or loss of
individual devices. Thread devices can also incorporate IPv6-based links such as Wi-Fi and Ethernet into the topology to reduce the
probability of multiple Thread partitions. This way, they can utilize the higher throughput, channel capacity, and coverage of those
infrastructure links, while still supporting low-power devices.
• Low power: Devices efficiently communicate to deliver an enhanced user experience with years of expected life under normal bat-
tery conditions. Devices can typically operate for several years on AA type batteries using suitable duty cycles.
• Cost-effective: Compatible chipsets and software stacks from multiple vendors are priced for mass deployment and designed from
the ground up to have extremely low-power consumption.
1.5 OpenThread
OpenThread released by Google is an open-source implementation of Thread®. Google has released OpenThread to make the net-
working technology used in Google Nest products more broadly available to developers, in order to accelerate the development of prod-
ucts for the connected home and commercial buildings.
With a narrow platform abstraction layer and a small memory footprint, OpenThread is highly portable. It supports both system-on-chip
(SoC) and radio co-processor (RCP) designs.
OpenThread defines an IPv6-based reliable, secure, and low-power wireless device-to-device communication protocol for home and
commercial building applications. It implements all features defined in Thread Specification 1.1.1, Thread Specification 1.2, Thread
Specification 1.3.0, and draft Thread Specification 1.4 (as of the release of this document).
Silicon Labs has implemented an OpenThread-based protocol tailored to work with Silicon Labs hardware. This protocol is available on
GitHub and also as a software development kit (SDK) installed with Simplicity Studio 5. The SDK is a fully tested snapshot of the Gi-
tHub source. It supports a broader range of hardware than does the GitHub version, and includes documentation and example applica-
tions not available on GitHub.
UG103.11: Thread Fundamentals
Introduction
silabs.com | Building a more connected world. Rev. 1.6 | 4