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Thread Wireless Networking Protocol

A new open wireless standard developed to balance and improve on the increasingly important requirements of reliability, security, power efficiency and cost.

Thread is a new open global wireless standard developed to balance and improve on the increasingly important requirements of reliability, security, power efficiency and cost effectiveness. Thread runs on the IEEE 802.15.4 physical radio specification and operates in the unlicensed ISM bands including 2.4GHz (v1.0).

The 802.15.4 specification the Thread stack operates on gained ratification by the Institute of Electrical and Electronics Engineers (IEEE) in 2003. The specification is a packet-based radio protocol that communicates in a variety of network topologies using batteries that can last several years.

The Thread Protocol


The Thread protocol has been created and ratified by member companies of the Thread Group, which includes many leading semiconductor manufacturers, technology firms, OEMs and services companies. Thread was created to combine the best of existing solutions while improving on reliability, security and ease-of-use.

Thread features include the following advantages:

  • Simple to setup and use
  • Always secure
  • Power-efficient
  • An open protocol that carries IPv6 natively
  • A robust mesh network with no single point of failure
  • Runs over standard 802.15.4 radios
  • Support for a wide variety of host devices

The network layer implements IPv6 addressing architecture with 6LoWPAN header compression and mesh capabilities for maximum routing efficiency and redundancy. Thread stack also features banking-class AES security and commissioning features across all layers of the IP stack, providing encrypted and secure but simple installation, start-up and operation. Another key advantage of Thread is that the application layer is separated from the actual Thread stack, making it agnostic and flexible for use with independently defined application layer standards, including the familiar ZigBee protocol as well as other popular protocols. This allows a level of forward compatibility between existing and new devices, making Thread attractive for designers and consumers alike.

Figure 1 (courtesy of Thread Group © 2015)

Mesh Networks

Like ZigBee, a key component of the Thread stack is the ability to support mesh networking. In a mesh network, nodes are interconnected with other nodes so that multiple pathways connect each node. Mesh networks are decentralized in nature; each node is capable of self-discovery on the network. Also, as nodes leave the network, the mesh topology allows them to reconfigure routing paths based on the new network structure. The characteristics of mesh topology and ad-hoc routing provide greater stability in changing conditions or failure at individual nodes.

Thread's mesh implementation (Figure 2), is based on the number of routers in the network. With Thread, a network can scale from a basic star topology with a single router to a large mesh topology with multiple routers. This flexibility in network formation makes systems more reliable by allowing radios to forward messages to other radios in a redundant fashion, eliminating the potential for single points of failure.

Figure 2 (courtesy of Thread Group © 2015)

Thread Applications

Thread enables broad-based deployment of wireless networks with secure, easy-to-provision, low-power solutions. It provides the ability to run for years on inexpensive batteries for a host of monitoring and control applications. While the Thread Group is focusing on the Home Automation market initially, significant deployments will be made in more industrial markets like industrial lighting, tank monitoring, and commercial/industrial solar where IPv6, security, and reliability are critical features.

Digi and Thread Group

Digi is a contributing member of the Thread Group. Through its membership, Digi is helping to advance this new technology and help customers connect devices to advanced wireless networks.

Digi is currently developing a new Thread-ready XBee® module that will be available in early 2016. XBee modules enable fast time-to-market, low RF development costs, rugged design and excellent range for those seeking to incorporate wireless capabilities into their products and solutions.

Joel Young
The Thread-ready XBee module provides Digi OEM module customers a simple migration path to quickly and easily drop a future-proof solution into their existing board designs,

Joel Young, Chief Technology Officer, Digi International
Read the press release

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