IoT is a network of interconnected things which enable  things to communicate and take actions even without human intervention.  A thing can be a living thing like an animal, plant or even a person or it could be a non-living thing like a device, vehicle or any other equipment. There is a need of a specific architecture to be followed for IoT.

In an IoT stack, “things” share information such as their working status in a cloud database, which can be utilized for the other “things” to coordinate their task.  In IoT, every “thing” has got a unique ID such as an IP associated to it. Information shared by the thing in the network, uses this unique identity for communication.

IoT Architecture Introduction

As a “thing” in the network lacks sensing or analysing capabilities, sensors and microcontrollers are attached to it. Thus meaningful and sensor based data is shared over the internet. Other things acquire this data with the help of receivers and coordinate their tasks based on the firmware programmed. The actuator integrated with the thing, then assists the action.

The discussion will be based on the seven layer architecture suggested by the Internet of Things World Forum Steering Committee which is widely becoming popular according to current trends.

L1 layer (Physical Devices and Controllers) 

The L1 layer consists of physical devices and controllers that might control multiple devices.  These are referred to as “Things” in IoT and they include of a wide range of devices that sends and receive information. This information will include the status of the device and information detected by the sensors, which is processed by a local controller and given for transmission using NFC.  IoT devices that are connected in the network are capable of A to D (Analog to digital) conversion when required. These can generate data and can be queried or controlled over the net.

L2 layer (Connectivity)

L2 layer relays information between devices, across different networks and between L2 and lower layer of L3. The important functions of L2 are:

• Communication between L1 devices.
• Reliable delivery across the network(s)
• Implementation of different protocols supported by the device
• Switching and routing
• Translation between protocols
• Security at the network level
• (Self-Learning) Networking Analytics

The device would be connected to internet using Wifi, Ethernet, 3G and other technologies. This Connectivity layer enables the device to send data to cloud and vice versa.

L3 layer (Edge Computing)

The ‘Edge computing’ layer formats the data into information that can be understood by L4 layer. The important function of L3 layer are:

• Data filtering, clean-up, aggregation & Validation evaluate if it is ok to be processed by L4.
• Formatting: Reformatting data for consistent higher-level processing
• Expanding/decoding
• Distillation/reduction: Compressing data to minimize the impact of data and traffic on the network and higher-level processing systems
• Assessment: Event generation in case of any alerts.

In short, Edge computing layer formats the data to save in a database. It also receives the data from internet and does filtering and normalization operations.

L4 layer (Data Accumulation)

As the sensor data keeps changing with time, L4 layer converts this data in motion to data in rest. Data accumulation layer stores the data in an easy accessible format. The layer dramatically reduces data through filtering and selective storing.

L5 layer (Data Abstraction)

Data abstraction layer or L5 layer takes the essential data that satisfies certain characteristics from the stored data and supplies it to the application layer for processing. The layer focuses on rendering data and its storage in ways that enable developing simpler, performance-enhanced applications.

L6 layer (Application)

Application layer or L6 layer processes data so that it will be accessible for every person or device to coordinate with the activities. It links the software layer with physical layer. This layer interprets data to generate reports for analytics and to apply business intelligence.

L7 layer ( Collaboration and Processes)

L7 or Collaboration and processes layer provides response or action to be taken against the data provided. This action, for instance can even be an actuation of an electromechanical device upon the instruction from the controller.

Conclusion

This is just one of the architectures proposed. IEEE is actively working on IoT Architecture for standardization. Once this comes into effect, we can fully tap the potential of Internet of Things.