IoT Network Architectures and Topologies

Architecture of IoT

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The architecture of IoT is divided into 4 different layers i.e. Sensing Layer, Network Layer, Data processing Layer, and Application Layer. 

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• Sensing Layer: 

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• The sensing layer is the first layer of the Internet of Things architecture and is responsible for collecting data from different sources.

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• This layer includes sensors and actuators that are placed in the environment to gather information about temperature, humidity, light, sound, and other physical parameters.

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• Wired or wireless communication protocols connect these devices to the network layer.

• Network Layer: 

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• The network layer of an IoT architecture is responsible for providing communication and connectivity between devices in the IoT system.

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• It includes protocols and technologies that enable devices to connect and communicate with each other and with the wider internet.

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• Examples of network technologies that are commonly used in IoT include WiFi, Bluetooth, Zigbee, and cellular networks such as 4G and 5G technology.

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• The network layer may include gateways and routers that act as intermediaries between devices and the wider internet.

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• It includes security features such as encryption and authentication to protect against unauthorized access.

• Data processing Layer: 

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• The data processing layer of IoT architecture refers to the software and hardware components that are responsible for collecting, analyzing, and interpreting data from IoT devices.

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• This layer is responsible for receiving raw data from the devices, processing it, and making it available for further analysis or action.

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• The data processing layer includes a variety of technologies and tools, such as data management systems, analytics platforms, and machine learning algorithms. These tools are used to extract meaningful insights from the data and make decisions based on that data.

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• Example of a technology used in the data processing layer is a data lake, which is a centralized repository for storing raw data from IoT devices.

• Application Layer: 

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• The application layer of IoT architecture is the topmost layer that interacts directly with the end-user.

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• It is responsible for providing user-friendly interfaces and functionalities that enable users to access and control IoT devices.

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• It includes middleware services that allow different IoT devices and systems to communicate and share data seamlessly.

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• It also includes analytics and processing capabilities that allow data to be analyzed and transformed into meaningful insights, machine learning algorithms, data visualization tools.

IoT Network Topologies: The Internet of Things (IoT), it is defined as the communication of sensors, actuators, and gateways with each other. Some common topologies are invaluable for IoT. In this article, we will discuss these common topologies.

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Point-to-Point Network (PPP):

It is possible for two points to communicate directly over PPP, which is one of the data link layer protocols.

• protocol, user control, data compression, and encrypted communication are possible.
• Example:Bluetooth connection between a mobile phone and a headset is an example of this topology.
• Advantages:Easy to configure and implement
• Less complex than other types of connections
• It is low cost
• Disadvantages
• Provides decentralized management
• Efficiency drops as the network grows

Bus:

• It is a network topology in which devices are connected to each other with a single cable.
• This cable is defined as the bus of the system. The signal travels through all stations. Each station checks the address of the signal and all stations that this signal passes along the way process the signal whether this address is relevant to them or not.
• Advantages:The cable structure is reliable.
• Adding a new station is easy.
• No central unit is needed.
• Disadvantages:Failure of one station disables the entire network.
• Fault detection is difficult

Ring:

• A ring topology is a bus topology in a closed loop.
• It accepts if the destination address is its own address. Otherwise, the incoming information will be out of the process.
• The information flow in the ring is unidirectional. In other words, the computers included in the ring are responsible for transmitting the incoming information.
• Advantages:All devices on the network have the same privileges
• New devices added to the network have minimal impact on performance
• Does not need any server
• Disadvantages:
• Failure of one device on the network means the entire network crashes
• It is quite expensive as the amount of cable used is large

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Star:

• Each device on the network is connected to router equipment such as a switch or hub with regulation capability in the center. The information sent from one station to the other first arrives at this central unit, and from there it is directed to the target.
• Advantages:
• Adding new devices to the network and removing existing devices is quite simple,
• Its structure and understanding are quite simple,
• In the Bus-Topology, only one device can send data at a certain time, while in the Star-Topology, more than one device can send and receive data on the line at the same time,
• Failure of a device on the network does not affect the data flow on the network,
• Detection of cable errors that may occur on the network is very simple.
• Disadvantages:
• Failure of the Switch / Hub in the center means the collapse of the network,
• Cable usage is quite high compared to other topologies.

Mesh:

In a mesh network topology, each device is connected to all other devices in the network via a dedicated point-to-point connection. Dedicated means that the connection carries data for only two connected devices. Let’s say we have n devices in the network, then each device must be connected to (n-1) devices in the network. The number of connections in a mesh topology of N devices will be (n * (n-1)) / 2.

• Advantages: There is no data traffic issue as there is a private connection between the two devices which means the connection is only available for these two devices. So this connection is secure.
• Mesh topology is reliable and robust. Because the failure of a link never affects other links and communication between other devices on the network.
• The mesh topology is secure because there is a point-to-point connection and therefore unauthorized access is never possible.
• Fault detection is quite easy in this topology.
• Disadvantages: The amount of cable required to create and connect the topology can get very tedious.
• The number of I/O ports required is very large as each device must be connected to other devices.
• There is a scalability issue. Because each device on the network has a private point-to-point connection. Therefore, it is not possible to send data to many devices at the same time.

Networking fundamentals: OSI and TCP/IP models

The OSI (Open Systems Interconnection) model and the TCP/IP (Transmission Control Protocol/Internet Protocol) model are fundamental frameworks for understanding how data is transmitted across networks. The OSI model is a conceptual, layered model, while the TCP/IP model is a practical, protocol-specific implementation, particularly for the internet. 

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OSI Model

• The OSI model divides network communication into seven layers, each responsible for specific tasks. This layered framework standardizes communication, supports interoperability, and aids troubleshooting.
• 7Layers:
• Application: User interface and network services (e.g., email, file transfer). 
• Presentation: Data formatting, encryption, and compression. 
• Session: Establishes, manages, and terminates connections between applications. 
• Transport: Reliable or unreliable data transfer (e.g., TCP/UDP). 
• Network: Logical addressing and routing (e.g., IP). 
• Data Link: Physical addressing and error detection. 
• Physical: Transmits raw bit stream over the physical medium. 

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Layer 7 – Application

• Function: Interfaces directly with user applications and provides network services (e.g. HTTP, SMTP (Simple Mail Transfer Protocol), DNS (Domain Name System)).�Facebook example: When you use the Facebook web or mobile app, the app uses HTTPS (HTTP over TLS(Transport Layer Security)) to interact with Facebook servers.

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Layer 6 – Presentation

• Function: Formats and translates data between the application and network; handles encryption and compression.�Facebook example: Images or videos you upload are compressed (JPEG/MPEG) and encrypted via TLS before sending to Facebook.

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Layer 5 – Session

• Function: Establishes, manages and terminates sessions between applications; coordinates dialog and checkpoints.�Facebook example: When you log into Facebook and open multiple browser tabs or device sessions, session layer protocols maintain your session state across those connections.

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Layer 4 – Transport

• Function: Ensures end‑to‑end data delivery, error recovery, flow control via TCP or UDP.�Facebook example: Data between your device and Facebook servers often uses TCP to reliably deliver feeds, messages, and images. Real‑time features (e.g. video chat) may use UDP for lower latency.

Layer 3 – Network

• Function: Handles routing using logical addressing (IP), packet forwarding across intermediate networks.�Facebook example: When you view a Facebook post, your IP‑based request is forwarded through routers over the internet to Facebook’s data‑center IP, and back.

Layer 2 – Data Link

• Function: Provides error‑free transfer between adjacent nodes; uses MAC addressing and frame control.�Facebook example: In your home or mobile network, your device connects to a Wi‑Fi access‑point or switch using MAC addressing and frame checks before packets leave your LAN.

Layer 1 – Physical

• Function: Transmits raw bits over physical medium—cables, Wi‑Fi radio waves, fiber optics, electrical signals.�Facebook example: The bits of your Facebook request travel over Ethernet cables, optic fiber, or cellular radio waves all the way to Facebook’s servers.

Example Scenario: Viewing a Facebook Photo

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1. Application: You click a photo in Facebook app → HTTP(S) request.
2. Presentation: Request is encrypted using TLS; image responses are compressed JPEGs.
3. Session: Your login session maintains state across tabs/devices.
4. Transport: TCP sends data segments reliably.
5. Network: Routing via IP ensures packets reach Facebook’s server and return.
6. Data Link: Frames sent over your LAN using MAC addressing, error detection.
7. Physical: Bits transmitted over Wi‑Fi, fiber, or mobile network.

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TCP/IP Model

• The TCP/IP model simplifies the OSI model into four layers. 
• Practical Implementation: It is the foundation of the internet and is used to implement actual network communication. 
• 4 Layers:
• Application: Combines the functionality of the OSI's Application, Presentation, and Session layers. 
• Transport: Handles reliable data transfer (TCP) or unreliable data transfer (UDP). 
• Internet: Defines logical addressing (IP) and routing. 
• Network Access: Deals with physical addressing and accessing the network medium. 

TCP/IP Model

• The TCP/IP model simplifies the OSI model into four layers. 
• Practical Implementation: It is the foundation of the internet and is used to implement actual network communication. 
• 4 Layers:
• Application: Combines the functionality of the OSI's Application, Presentation, and Session layers. 
• Transport: Handles reliable data transfer (TCP) or unreliable data transfer (UDP). 
• Internet: Defines logical addressing (IP) and routing. 
• Network Access: Deals with physical addressing and accessing the network medium. 

Model Comparison

Summing Up

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The TCP/IP model drives today’s Internet and most modern networks. It’s the practical, real-world protocol suite in daily operation, optimized for scalability and performance.

The OSI model remains valuable as a teaching tool and troubleshooting framework. Its layered abstraction helps network professionals conceptualize and communicate about networking concepts.

When asked “Which is used now, TCP/IP or OSI?”: TCP/IP is used operationally, whereas OSI is used for educational and conceptual clarity.

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