Specifically, the two groups have announced that the ZigBee Cluster Library Application Protocol will run on Thread Networks. This may seem like a minor step, but it could help break a log-jam of competing, partially overlapping approaches to the wirelessly connected smart home.
The ZigBee Cluster Library is a set of functions and commands that can be used to build applications divided up into sector specific groups. These groups include: general, lighting, sensors, industrial, HVAC and security. Thread networks are defined as IPv6-based routing on top of 6LoWPAN together with security and commissioning protocol, all riding on 802.15.4
Google subsidiary Nest Labs founded Thread in 2014 with Samsung, Freescale Semiconductor, ARM, Yale Security, Silicon Labs and Big Ass Fans (see Google Launches Smart Home IoT Protocol). With such a strong set of founders, it is no surprise that the group has gathered more than 50 members.
As both ZigBee and Thread are defined to exist on top of the IEEE802.15.4 standard for low-rate wireless communications, the move does not have to be a great technical stretch. In essence, ZigBee provides a well-established application-level wireless standard, while Thread is adding IPv6 routing security. The two together could provide a standard end-to-end protocol with significant industry support.
It therefore also serves as a starting point in trying to reduce the multitude of approaches to short-range connectivity and the Internet of Things (IoT). Unchecked fragmentation raises the cost of deploying and adopting the technology and thereby limits the pace of adoption.
The two groups say, that by working together, they can provide an interoperable solution to help streamline product development and ultimately improve the consumers’ experience in the connected home.
While cooperation can clearly bring benefits, both ZigBee and Thread say they remain committed to their independence but will cooperate to benefit their respective members.
"By agreeing to work together, ZigBee and Thread are taking a big step towards reducing fragmentation in the industry," says Chris Boross, president of the Thread Group and technical product marketing manager at Nest, in the statement.
"Thread is designed to work with and support many different application layer protocols, and we look forward to working with ZigBee to create a combined solution for the connected home,” Boross says.
However, the move also represents a bit of a turnaround for Thread, according to Lee Ratliff, principal analyst for connectivity and IoT at IHS. "At Thread's foundation, it was critical of ZigBee application profiles. Thread argued they interoperability issues and used them as an argument for the creation of Thread," says Ratliff.
He continues: "Whether this is a big deal or small deal depends on what happens next. The Thread specification is not complete and not published. Thread stops just below the application layer and they have not said before how they intend to solve that. But it does become Thread's problem. Somebody has to worry about end-to-end interoperability.
GreenPeak Technologies BV (Utrecht, The Netherlands) is a supplier of
IEEE 802.15.4 and ZigBee RF connecitivity and controller ICs and a member of the ZigBee alliance. GreenPeak CEO Cees Links welcomes the move by ZigBee and Thread, which he says provides ZigBee with a clear IP routing strategy and the Thread Group with a standard for application profiles.
"However, it is clear that a lot of work needs to be done to get this all in place, including proper test specifications and certification procedures," Links says. Links highlights three challenges that remain to be addressed but are not in the initial announcement from the two industry organizations. These are:
1) Coexistance and migration of the ZigBee PRO networking layer and the Thread networking layer.
2) Integration of ZigBee Green Power (ultralow power) end devices in a Thread environment.
3) The bridging of RF4CE ZRC2.0 capabilities across ZigBee/Thread networks.
"In principle all the key components are available to build an efficient IoT local area networking environment, but to make this secure, power efficient, easy to use (self-install) and cost effective at the same time will be a challenge," says Links. "This announcement positions two credible IoT standardization bodies to provide direction for the first end-to-end protocol, including IEEE 802.15.4 (for the physical layer), IETF 6LoWPAN (for the networking layer) and the ZigBee Cluster Library (for the application layer). At first glance, this may appear as a small step, but in the near future this step could become a key milestone in the development of the IoT and the Smart Home," concludes Links.
"This isn't the end-game for Thread,” Ratliff says. “It may have been done to provide immediate interoperability of networking, to kickstart a Thread user community. Maybe they intend to supplement this with other application profiles such as Alljoyn. Clearly, ZigBee also gets something. They get to keep close to Thread."
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