What is the Web of Things?
The Web of Things (WoT) seeks to counter the fragmentation of the IoT by using and developing existing standardized web technologies. W3C WoT enables easy integration between IoT platforms and application domains by providing standardised metadata and other reusable technology building blocks.
Connect everything to the Internet and give them an IP address in the first step to the Internet of Things. Things could easily exchange data with each other, but you don’t necessarily understand what that data means.
This is what web protocols like HTTP have brought to the Internet: a universal way of describing images, text, and other media so that machines can “understand” each one. The WoT is simply the next step in this evolution: using and adapting web protocols to connect whatever in the physical world and attend the World Wide Web!
The Architecture of the Web of Things
Just the OSI layer architecture organizes the many protocols and standards of the Internet. The WoT architecture attempts to structure the galaxy of protocols. And web tools into a useful framework for connecting any device or thing to the Internet Web.
The WoT architecture stack is not made up of layers in the strict sense, but layers add additional functionality, as shown in the following figure. Each layer allows WoT to be even more intimately integrated and makes these devices more accessible to applications and humans!
To demonstrate what these layers bring to the IoT table, we’ll showcase the WoT Pi, a Raspberry Pi device running at EVRYTHNG in London. The WoT Pi connect to a series of sensors (e.g. temperature, humidity) and actuators (e.g. LCD screen, LED) with which it can interact via the Internet.
Layer 1: Access
This layer is responsible for turning anything into a web object with HTTP requests like any other reserve on the Mesh. In different words, a WoT is a REST API that lets you interact with it somewhat in the real world, like opening a door or reading a temperature sensor situated anywhere on the planet.
Go ahead and stab this in your browser. You will get user-friendly HTML rendering with links to the sensors. Click on “temperature”, and you will get the temperature. What you are doing here is browsing our Pi’s RESTful API, just like you are browsing a web page.
This is all good, but numerous IoT scenarios are real-time and event-driven. Rather than your app continually requesting data from our Pi, you want to be notified when something is happening in the real world. For example, the humidity hits a certain threshold or noise is detected at night. This is where another web protocol can offer assistance: WebSocket.
This Javascript code below is enough for a webpage to get temperature updates from the WoT Pi automatically. You can paste it into your web browser’s console, and you will see our Pi push the temperature every second to your browser.
Layer 2: Research
Reporting things accessible through HTTP and the WebSocket API is great, but that doesn’t mean that applications can actually “understand” what Thing is, what data or services it offers, etc.
This is where the second layer, Research, gets interesting. This layer ensures that your Thing can not only be easily used by other HTTP clients. But can also be automatically found and usable by other WoT applications. The approach here is to reuse semantic standards from the Web to describe things and their services.
This lets you search for items through search engines and other web indexes. The automatic generation of operator interfaces or tools to interrelate. At this level, technologies such as JSON-LD use a language for semantically annotating JSON. This is also where values such as the Web Things Model and the work of the W3C WoT group help them define an abstract set of REST resources that Things should offer.
Layer 3: Share
The Internet of Things will only thrive if things have a way to share data between departments securely. This is the accountability of the Share layer, which specifies how the data generated by Things can share efficiently and securely on the Website. At this level, another package of web protocols helps.
First, TLS, the protocol that protects transactions on the Website. Then, techniques such as delegate web authentication mechanisms such as OAuth can integrate into our Things APIs. Lastly, we can also use social networks to part objects and their resources to create a social network of things!
Layer 4: Compose
Finally, once the objects are on the Web (Layer 1) where humans and machines can find them (Layer 2) and their resources can safely share with others (Layer 3). It’s time to see how to build large, meaningful and scaled applications for WoT. In other words, we need to comprehend the integration of heterogeneous object data. And services into a huge ecosystem of web tools, such as analytics software and mashup platforms.
Composition layer web tools range from web toolkits (for example, JavaScript SDKs offering top-level abstractions) to panels with programmable widgets. Finally, physical mashup tools like Node-RED, as shown below. Taking inspiration from participatory Web 2.0 services and, in particular, web mashups, physical mashups provide a unified view of the classic Website and the object. And allow users to create applications using data and web object services without the need for knowledge programming.
Conclusion
Web of Things a high-level application protocol design to maximize interoperability in IoT. And we hope this short outline gives you an idea of its potential. Website technologies are very popular and provide all the flexibility and functionality needed for most upcoming IoT applications. It including discovery, security, and real-time messaging.
Also Read: Wireless Sensor Networks – Definition, Applications, Design Issue, and More