In the past decade, numerous technologies have emerged transforming industries, homes, and offices. One such technology which has revolutionized device interoperability and the way humans work and interact is the Internet of Things. The Internet of Things has allowed sophisticated connectivity between devices while ultimately leading to development of more intelligent solutions across geographical regions and industries. However, any developer aspiring to establish a career path in this domain must inculcate diverse skillsets. The IoT market is growing, employing millions of developers around the world. The market value is also growing steadily and is expected to cross $630 billion in 2025 as per the latest data. With growing IoT solutions all around the world, the IoT market is expected to grow even further.
The point is that the developers aspiring for a career in IoT must understand its fundamentals and core concepts deeply. And one of the core concepts that is comprehensively covered in IoT interview questions is logical and physical design of IoT. Having complete knowledge of physical and logical framework enables IoT developers to understand effective executions.
In this blog, let us comprehensively discuss IoT logical and physical design. The blog will touch upon numerous components and their interoperability that will lead to reliable, effective, and scalable IoT solutions.
Let us begin from absolute basics. However, before we do that, let us slightly digress and understand what IoT is first.
What Is IoT?
Internet of Things can be defined as an interconnectivity between intelligent devices having embedded sensors or actuators. This powerful interconnectivity allows devices to share real-time data. It provides numerous advantages in home automation and industrial applications. This is why its adoption is accelerating worldwide. The use of IoT is across industries encompassing healthcare, weather monitoring systems, smart homes, smart cities, manufacturing, etc.
Basics of Logical and Physical Design of IoT
Even if you are a novice in the world of Internet of Things, you must be familiar with smart devices like your smartphone, smartwatches, laptops, Amazon Alexa, etc. Ranging from smart thermostat, fitness tracker, to a biometric scanner in your office. All these devices are nothing, but a real-life application of a useful concept called Internet of Things. Have you ever wondered what makes such devices truly intelligent? They are the fundamental design architectures.
And, the design architecture of any IoT environment can be widely categorized into two main types:
- IoT Physical Design.
- IoT Logical Design.
Let us explore the design architecture in further detail-
Logical Design: The IoT’s Brain
Imagine that an IoT is not a collection of various systems but a single entity. The brain of the entity is the logical design. Basically, logical design is nothing but the brain of the complete IoT environment. It defines the flow of information, how IoT devices share data, and how the information is processed and stored in the environment. The logical design concept helps IoT developers determine protocols, data models, and numerous rules that define the operation of IoT platform.
Physical Design: The IoT’s Body
With logical design, we have defined the brain of the IoT ecosystem. However, in order to make the IoT work, we also require a functional body. The body of IoT is defined by the physical design that includes sensors, microcontrollers, and network infrastructure that can share and collect data in the real world. IoT physical design comprise of actual device that you can touch, feel, observe, and interact with in the real world. It holds the responsibility for implementing IoT capabilities in the real world.
Understanding both logical and physical design of IoT is crucial because they are connected with one another and interoperate. No matter how advanced your sensors are, they will only function correctly in an IoT environment if you have implemented the correct data protocols. On the other hand, a reliable software architecture needs strong hardware for effective deployment.
In the succeeding sections, let us understand both components of the design architecture:
Physical Design of IoT
The physical design of IoT involves physical devices connected to an IoT environment and the protocols leveraged to ensure an active IoT environment. Every IoT device comprise of specific tasks such as actuating, remote sensing, etc., based on the IoT environment they are connected to. Such devices can also transfer data and share files via distinct types of wired or wireless connections. They can create data, which is leveraged to perform analysis and operations for enhancing the system.
Now, let us discuss the two main elements of IoT physical design: IoT node devices and IoT communication protocols.
Node Devices
Node devices are utilized to establish a connection, process information, render interfaces, and store data in an IoT ecosystem. Note devices create data that can be assessed by the IoT environment and programmed to execute processes and enhance the system.
Now, from the following points, let us try to understand which devices are applicable for which function in an IoT environment.
- Audio/Video Interfaces: System interfaces such as RCA and HDMI devices record videos and audio.
- Connectivity: Devices such as Ethernet and USB hosts ensure connectivity between the server and devices.
- Processor: Processors such as the central processing unit and other units process the information. This is utilized to enhance the decision quality of an IoT environment.
- Input/Output: Devices such as SPI, UART, CAN, etc., provide input and output signals to IoT sensors and IoT actuators.
- Activity Control: Devices such as GPU and DDR control the IoT system activity.
- Storage Interfaces: IoT devices such as MMC, SD, and SDIO are used for storage of data.
IoT Protocols
IoT communication protocols help in establishing a connection between the node device as well as the server via the internet. Essentially, it sends commands to an IoT device and then receives data from the IoT device. Both client and server side depend on distinct types of protocol. Furthermore, these IoT communication protocols are managed via network layers. The main types of network layers include transport, application, network, and link layers. IoT communication protocols are one of the pillars of logical and physical design of IoT.
Some of the protocols are
- HTTP (Hyper Text Transfer Protocol)- This protocol is utilized for transmitting media documents by establishing a communication link between servers and web browsers.
- Application Layer Protocol: Protocols used in this layer define how the information is being sent over the network. It depends on underlying link, transport, and network layer protocols to deliver the information across the network. Examples of Application layer protocol includes: WebSocket, MQTT, XMPP, AMQP, and DDS protocols.
- Web Socket: It allows two-way communication between the host and the client and mostly web browsers leverage it.
- Transport Layer: It controls the overall flow of data segments. Moreover, it also manages error-control and end-to-end capability for message transfer.
- Transmission Control Protocol: It sets up and maintains a network that can ensure data exchange via the internet protocol.
Different types of network layer are as follows-
- Network Layer: In IoT, the network layer is basically used to send datagrams from the source network to destination network. Main examples of network layer include IPv6 and IPv4.
- Link Layer: The link layer is utilized to send data over the physical layer of the network. It defines how the packets are being programmed and signaled by the devices.
- Ethernet: It is a comprehensive set of protocols utilized in Local Area Networks that defines the medium access control and physical layer of LANs.
- Wireless Fidelity (Wi-Fi): It is a group of LAN protocols. It defines the set of media access controls and physical layer for LANs.
Logical Design of IoT
It is the actual design of the IoT system. It illustrates the assembling and configuration of the components i.e. computers, sensors, and actuators.
As stated earlier, logical design describes the brain of the IoT system. It describes the configuration and assembling of components, which includes sensors, computers, and actuators.
The various components of IoT Logical Design are as follows:
- IoT functional blocks.
- IoT communication models.
- IoT communication APIs.
- Web-Socket-based Communication API
1. IoT functional blocks
The IoT functional blocks render identification, sensing, management, actuation, and communication capabilities to the IoT environment. The devices included in the functional blocks manage the communication between the host and the server. This allows tracking of control functions, handling the data transfer, protecting the IoT system via authentication, and ensuring an interface for tracking and controlling numerous functions. IoT functional blocks are one of the most crucial aspects of logical and physical design of IoT.
The functional blocks of IoT include the following:
- Device: Devices render actuation, sensing, tracking, and control functions to the IoT platform. The common devices used in the IoT ecosystem include the following sensors, RFID tags, appliances, actuators, machines, and gadgets. These devices can be tethered to the IoT environment either via wireless chip or cable.
- Communication: It handles communication within the IoT environment. Communication is a crucial facet of the entire IoT framework as this makes IoT devices capable of communicating with another platform or with one another.
- Services: Services cover various functionalities like device control, device tracking, device discovery, and data publishing. In Internet of Things, there is a management service layer which is responsible for handling these services.
- Management: This functional block provides functionalities to control the IoT system. It includes numerous functions such as controlling and handling the devices, enforcing standards of security, implementing data encryption and segmentation, etc.
- Security: It ensures security for the IoT platform. It performs authorization, authentication, data security functions, and message and content integrity. Security helps in safeguarding devices and save details from manipulation, theft, and unauthorized accessibility.
- Application: The application functional block provides an interface where users can track and control numerous facets of the IoT system. It empowers users to check the status of the system and assess the processed data. The user-friendly interface helps users to ensure effective use of the collected data.
2. IoT Communication Models
The purpose of IoT communication models is to ensure strong communication between the server and the system. The various types of IoT communication models include the following:
Request-Response Model:
In this model, there is a client that transmits request signals to the server and then the server responds to the request. Once the request is received, the server then chooses how to respond by retrieving the data, fetching the resource representation, creating the response, and sending responses to the client. In this model, the protocol followed between server and client is HTTP.
Publish-Subscribe Model:
The model comprises of three main entities: Brokers, Publishers, and Consumers.
- Publisher: It is the data source that transfers data to the topic.
- Consumers: In the publisher-subscribe model, the consumer subscribes to various topics.
- Brokers: The brokers then accept the data sent by the publishers and send it to the consumers.
Push-Pull Model:
The model comprises of data consumers, data publishers, and data queues:
- Publishers: In the push-pull model, the message is first published by the publishers and then pushed in the queue.
- Consumers: Consumers remain present on the other side and get the data out of the queue.
- Queue: It aids in decoupling the message between consumer and producer.
Exclusive Pair:
Exclusive pair forms the bi-directional model that involves full-duplex communication between the server and client. In this model, the client first sends the request, and the server stores the record of all the connections. Here, only the WebSocket-based communication API is utilized.
IoT Communication API:
There are two distinct types of communication API:
REST-driven Communication API:
The full form of REST is Representation State Transfer. It involves a complete set of architectural protocols via which you can design web APIs and web services. Such APIs and web services focus on the resources of the system and how the resource states are being sent and addressed. It depends on a request-response communication model, and the architectural aspects include connectors, components, and data elements. They collaborate via a distributed hypermedia system.
The main benefits of REST-based communication APIs involve the following:
Flexibility: REST APIs support a diverse range of applications and services. They can provide support to straightforward web apps to a more complete enterprise platform.
Simplicity: The process to design and deploy REST API does not involve any complications. This is precisely the reason why it has emerged as a preferable choice for creating APIs for web applications.
Stateless: Every request in REST API is independently processed and is not associated with previous requests. This simplifies distribution and scalability.
Caching: REST APIs depend a lot on caching to improve performance and reduce service load.
Web-Socket-driven Communication API:
Web-Socket API can be described as the full-duplex and bi-directional communication model between servers and clients. It does not need a fresh connection to set up for every message between servers and clients. Once the connection is established, the messages can be consistently sent and received without disruption. It is an ideal choice for IoT applications with specific needs such as high throughput and low latency.
Go through the following points to understand the benefits of web-socket-based communication APIs:
- Scalability: Since they can render support to a vast range of connections (up to thousands) per each server, Web Socket APIs prove to be extremely scalable.
- Efficiency: Web Socket APIs prove to be more efficient in real-time communication. They depend on consistent communication to ascertain bidirectional communication.
- Reduced Overhead: When compared to Rest APIs, it has comparatively less overhead since it relies on single-point communication to transfer information.
- Real-time Communication: Web Socket APIs are the best option for applications that rely on real-time updates. They are more widely preferred because they allow strong communication between client and server in real-time.
Fog and Edge Computing in IoT Architectures
As IoT networks start to become more layered and decentralized, extensively relying on cloud infrastructure can cause performance issues. To fix this problem, edge and fog computing are vastly integrated in IoT logical design.
As far as edge computing is concerned, the information is processed locally either via gateways or routers or within the device. This proves to be crucial for latency-sensitive application areas such as autonomous vehicles, smart cameras, or predictive maintenance in factories. Fog computing ensures intermediate processing between remote cloud infrastructure as well as local edge nodes, allowing real-time analytics and bandwidth optimization.
When edge and fog computing are combined, they improve scalability, efficiency, and responsiveness of IoT deployments while proving to be compatible with distributed and modular architecture.
Security and Privacy in IoT Design
As the number of connected platforms expands, emphasizing privacy and security becomes a vital aspect of IoT physical design. Without effective protection, IoT connectivity can become vulnerable to data breaches, unauthorized access, and unauthorized modifications at the device level.
From physical enclosures and safe boot mechanisms to end-to-end encryption and access control, every layer need protection. Protocols required for network encryption make sure that network encryption is secure while application-level controls such as token-based authentication and Application Programming Interfaces protect user access.
Privacy concerns also require proactive solutions. Specific techniques like anonymization, data minimization, and compliance with GDPR/CCPA standards ensure that the personal data is handled responsibly. Incorporating zero-trust models for dependable hardware elements and security into physical design makes it quite easy to create resilient and compliant IoT ecosystems.
Comparing Logical Designs of IoT and Physical Designs of IoT
The following table expound on the main difference between logical and physical design of IoT:
| Aspect | Physical Design of IoT | Logical Design of IoT |
| Definition | Comprises the tangible devices and components utilized in the IoT platform. | It involves the abstract system describing the functionality of an IoT system as well as the data flow. |
| Focus | Hardware elements such as actuators, sensors, devices, network infrastructure, and communication modules. | Interaction models, software architecture, data processing, and communication protocols. |
| Components | Includes gateways, IoT devices, cloud servers, RFID tags, physical network setups, and cloud servers. | Involves message queues, APIs, event-based logic, data formats (XML, JSON), and services. |
| Representation | Covers the type of devices that exist and their placement in the network. | It deals with how devices process, communicate, and share data. |
| Example | One of the common examples is a Wi-Fi module sending information to the cloud. | The logical design covers transmission of data through MQTT protocol and assessed via stream-processing service. |
Conclusion
The Internet of Things is one of the pillars that drives the advanced technological solutions that we see today. A few of the main examples of IoT include connected cars, smart appliances, intelligent agriculture equipment, healthcare monitors, etc. The significance of IoT exists across niches, industries, and geographical locations. It is quite valuable in weather monitoring systems, healthcare platforms, and smart cities. However, to create an effective and smart IoT ecosystem, IoT developers must be sound in their technical skills.
In this blog, we have focused on one of the fundamental aspects of logical and physical design of IoT. They are the cornerstones of every successful IoT system.
While physical design of IoT deals with the infrastructure of the IoT system, logical design emphasizes intelligence and interaction models. The physical design involves tangible components such as sensors or actuators as well as communication models. On the other hand, the logical design focuses on functional blocks, communication models, and API. In order to drive success in every IoT development project, it is critical to understand how physical and logical design work and their interoperability.
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