Connect the Dots: Use ZigBee’s dotdot Protocol to Simplify IoT Device Connectivity

Create: 02/10/2017 - 17:43

You can’t have a Connect the Dots blog for IoT solution providers and not discuss dotdot, the new – new – universal language for connecting IoT devices. The protocol is still being birthed by the ZigBee Alliance, but by 2018 certified “smart” objects will be able to work together across any network.

The basic problem being addressed by dotdot is one that every solution provider runs into at some point: devices are on different networks, wired or wireless. Then, even if they are on the same network, they don’t use the same communications protocols. This leads to extra time, effort and processing horsepower being dedicated to protocol translation instead of application development and execution.

The inefficiency of this need to support multiple protocols is anathema to the fundamental IoT requirements for ultra-low power consumption and ease of connectivity. Any toaster needs to talk with any coffee machine, and any light bulb needs to chat with any light switch, or energy meter or any number of sensors, actuators or monitoring devices and systems.

This is why the competing AllSeen Alliance with its AllJoyn framework and the Open Connectivity Foundation (OCF) with its IoTivity framework joined under the OCF name and bylaws (Figure 1). The group is open source and is dedicated to finding common ground for connectivity, security and programmability.


Figure 1: The drive for efficient, universal IoT connectivity drove the founding members of the AllSeen Alliance and OCF to merge the IoTivity and AllJoyn framework efforts. (Source: Linux Foundation)

In a further sign of consolidation and a desire to find common ground, the UPnP Forum merged under the OCF in January.

For its part, dotdot is the ZigBee Alliance’s way of rebranding the upper layers of the ZigBee specification that fall under the ZigBee Cluster Library (ZCL). The ZCL is divided into a number of functional domains, each one addressing clusters related to specific functionality. Example clusters include HVAC, lighting, security and safety and measurement and sensing. The ZCL is analogous to the Bluetooth profiles for audio, human-machine interface devices (HIDs), printing, cordless telephony and others.

The essential goal is to completely abstract the underlying network layer from application-layer, device-to-device communications (Figure 2). In this way, smart objects can discover each other and recognize each others’ functions and communicate efficiently and securely, with human interaction being optional.


Figure 2. The dotdot protocol unifies the ZigBee application layers so devices can communicate efficiently regardless of explicit function. (Source: ZigBee Alliance)

The dotdot paradigm has already been demonstrated over Thread’s IP-based network and specifications and certification will roll out during the coming year.

The OCF and the ZigBee Alliance have memberships in the hundreds, many of which overlap. Further consolidation around a common protocol is required. The IoT is moving too fast and has too much potential to worry about differentiating at the physical and network layer.

The future is in the intelligence that can be gathered from connected devices and applying that intelligence toward better processes and outcomes. The present lies in first getting them to talk to each other.

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Patrick Mannion
Patrick Mannion is an independent writer and content consultant who has been working in, studying, and writing about engineering and technology for over 25 years.

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