Physical and Logical Design of IOT

Physical and Logical Design of IOT

1 September 2023 0 By Anshul Pal

In this article we discuss about the Physical and Logical Design of IOT. The Internet of Things (IoT) is when everyday things like your fridge or your car are connected to the internet so they can talk to each other and share information. This is getting really popular, and companies are using it to work better and save time. But, it’s not always easy for companies to figure out how to use IoT in their daily work.

Physical and Logical Design of IOT

There are two important parts to making IoT work: how you plan it and how you build it. We breakdown both them into Physical and Logical Design of IOT:

  1. Planning it (Logical Design): This is like drawing a map of how everything will work together. It’s like making a plan without getting into all the tiny details. It’s more about the big picture of how things will talk to each other and share information. But it doesn’t say exactly what technology or products to use.
  2. Building it (Physical Design): This is like actually making all the things in the plan. It’s not just about making products, but making a smart system that works well for people using it. It’s important to make sure the design fits what people need. In the planning part, we understand how things are related logically, but in the building part, we figure out the best way to store and get the information.

So, we breakdown both Physical & Logical Design of IOT in two parts – Logical design is like making a general plan of how everything will connect, while physical design is about actually creating a smart system that meets people’s needs.

Physical Design of IOT

The idea of Physical Design in the world of IoT is about IoT Devices and their matching IoT Protocols. We can consider these “Things” as Node devices. Which hold distinct identities and have the ability to perform tasks such as remote sensing, actuation, and monitoring. IoT Protocols play a vital role in establishing a seamless connection between these Things and a cloud-based server across the vast expanse of the Internet. These protocols serve as the set of rules and methods that facilitate effective communication between these Things and the central server, forming the backbone of the IoT ecosystem’s connectivity.


In simple terms, “Things” are the special devices used in IoT. They have their own names and can do things like sensing from a distance, controlling stuff, and keeping an eye on things. These Things are the important parts of IoT setups. They can be all sorts of devices like sensors, smart watches, electronic gadgets, wearable sensors, cars, and big machines in factories. These devices generate various types of information, and when specific computer systems organize this information, they provide valuable insights that help us decide what to do next, whether it’s something close by or far away.


For example, Temperature data generated by a Temperature Sensor in Home or other place. When processed can help in determining temperature and take action according to users.

Above picture, shows a generic block diagram of IoT device. It may consist of several interfaces for connections to other devices. IoT Device has I/O interface for Sensors, Similarly for Internet connectivity, Storage and Audio/Video.

IoT devices gather data from sensors either on their own or connected to them. They send this data to other devices or cloud-based servers. These days, we have many cloud servers made just for IoT systems. People call these special platforms “IoT Platforms.” They’re created specifically for IoT requirements, which makes analyzing and processing data a straightforward task.

Logical Design of IOT

A logical design for an IoT system is like planning how to set up its parts (like computers, sensors, and actuators) to do a certain job. It doesn’t get into detailed instructions about building each part with technical programming details. For understanding Logical Design of IoT, we describes given below terms.

  • IoT Functional Blocks
  • IoT Communication Models
  • IoT Communication APIs

IoT Functional Blocks

IoT systems consist of various functional blocks like Devices, communication, security, services, and management. These blocks offer abilities for sensing, identification, actuation, management, and communication. Inside these functional blocks, there are devices that manage communication between the server and the host, enable monitoring and control functions, handle data transfer, ensure IoT system security through authentication and other functions, and provide an interface for controlling and monitoring different aspects.

The functional blocks are as follows:

  1. Device: IoT systems include devices that can sense, actuate, monitor, and control functions.
  2. Communication: This block manages the communication within the IoT system.
  3. Services: It offers services like device monitoring, device control service, data publishing services, and device discovery services.
  4. Management: This block provides various functions to oversee the IoT system.
  5. Security: This block ensures the security of the IoT system by offering functions like authentication, authorization, message and content integrity, and data security.
  6. Application: It’s an interface that users can utilize to control and monitor different aspects of the IoT system. The application also lets users check the system status and view or analyze the processed data.

IoT Communication Model

The Internet of Things (IoT) enables various ways for entities within an IoT system to communicate. These communication methods include the following:

  1. Response Request Model: The Request-Response Model is a crucial framework that involves two main entities: the client and the server. The client can take various forms, such as a web application or a mobile app, and its purpose can range from browsing web pages to accessing emails.
  2. Publish-Subscribe Model: The Publish-Subscribe Model is a way of communication that has three main parts: the publisher, consumer, and broker. In this setup, the publisher regularly sends out messages, often at set intervals. For example, in IoT, sensors can act as publishers, providing data as topics. The broker acts as a central hub that manages different topics for consumers to subscribe to. Usually implemented as a server, the broker keeps track of the messages published by the publishers. Consumers, typically represented by IoT apps that users use, access the data published by the publishers. Consumers can subscribe to one or more topics managed by the broker.
  3. Push-Pull Model: In the push-pull model, there are three main parts: the publisher, the consumer, and the queues. Publishers are responsible for pushing messages into the queues. The data they create is then stored in one or more queues.

    One key difference between the push-pull model and the publish-subscribe model is how messages are ordered. In the push-pull model, consumers take the initiative to pull messages directly from the queues and then consume them. Typically, a consumer in this context refers to an IoT application that helps users interact.

  4. Exclusive Pair Model: The Exclusive Pair Model works with two main entities: the client and the server. These entities create a full duplex connection to facilitate the exchange of data.

IoT Communication APIs

An Application Programming Interface (API) works as a standardized way to access server resources. APIs act as middlemen that enable IoT devices to interact with the Internet and other interconnected elements in the network.

Websockets API IoT

In the realm of IoT, there are two main types of communication APIs:

  1. REST-based Communication APIs: REST-based Communication APIs, which stands for Representational State Transfer, consist of a set of principles for designing web services and web APIs. REST mainly focuses on effectively managing a system’s resources and ensuring smooth handling and transfer of resource states. APIs developed in this manner follow REST’s request-response model and adhere to specific architectural constraints that apply to components, connectors, and data elements within the system.
  2. WebSocket-based communication APIs: WebSocket-based communication APIs enable full-duplex communication between clients and servers, following an exclusive web pair communication model. This communication method is known for its stateful nature, allowing continuous and efficient interactions.


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