SAN JOSE, Calif. — Even before its $3.2 billion acquisition by Google, Nest Labs was quietly building into all its products a low-power mesh networking protocol. Now it hopes to make it an industry standard, called Thread, for home automation devices.
A handful of chip and system makers, including ARM, Freescale, Silicon Labs, and Samsung, have joined the ad hoc Thread Group led by Nest. It aims to release the royalty-free protocol this year to anyone who joins the group.
Thread is one of a growing number of efforts to unify or supply some missing piece for the highly fragmented Internet of Things sector. In an interview with EE Times, Chris Boross, a technical marketing manager with Nest and president of the Thread Group, explained why current protocols for consumer home automation products don't meet its requirements.
Thread is an implementation of a 6LoWPAN software stack that is based on IPv6 and includes IP routing. It supports, over IEEE 802.15.4 radios, a mesh network handling up to 250 nodes with encryption and authentication required for each node.
“WiFi is great. Nest uses it in all its products, and that won't change,” says Boross. “But we think there needs to be a second network, a device-to-device mesh.”
Nest embeds 15.4 radios and an early version of Thread in all its products, he tells us. A Nest thermometer teardown last year by the editor of IoT World (a sister site) uncovered a Silicon Labs EM357, which has a 2.4 GHz 802.15.4-2003 transceiver.
Thread is built for use in any home automation product, including items Nest currently does not make, such as lighting and security systems. Big Ass Fans and Yale Security are also founding members of Thread, signaling their plans to use the protocol.
Boross downplays concerns that OEMs might shy away from using technology from a competitor, especially one with the backing of Google. The new protocol is being developed “as an industry initiative. It's not just about Nest.”
Thread is designed to be limited to residential products. “We are not trying to solve for industrial use cases, because they have other requirements.”
The protocol uses AES encryption at the 802.15.4 MAC layer and will release details this year about its authentication technique that uses “pieces of existing technologies wrapped into something new,” Boross says. “All Thread networks are always secure, all traffic is encrypted, and all nodes authenticated by default.”
The protocol operates at the UDP level and supports any IPv6 application layer protocol (see chart). Thus Thread devices could be controlled by Android, iOS, or Windows PCs, phones, or tablets using an IPv6 link, probably over WiFi. Boross expects some devices to act as bridges between WiFi and 15.4 networks.
Thread will release terms for membership this year. Once members pay an annual fee, they will get access to the specification to use on a royalty-free basis.
The group plans to create a certification program in the first half of next year, when initial products are expected to ship. Freescale expects to provide a version of Thread with many of its chips geared for home automation systems — a path other chip vendors in the group are likely to follow.
Boross says the group has no roadmap beyond a 1.0 specification coming this year. It aims to maintain a single version as long as possible to reduce fragmentation and interoperability issues.
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