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Table of contents
1.
Introduction
2.
Layered Architecture
2.1.
Core Components of the Layered Architecture
2.2.
Advantages of Layered Architecture
2.3.
Disadvantages of Layered Architecture
3.
OSI Model
3.1.
Advantages of OSI Model
3.2.
Disadvantages of OSI Model
4.
TCP/IP Model
4.1.
Advantages of TCP/IP Model
4.2.
Disadvantages of TCP/IP Model
5.
Frequently Asked Questions
5.1.
What are the 3 types of network models?
5.2.
Why use a network model?
5.3.
Is TCP a session layer?
5.4.
Explain what the TCP/IP Reference Model is.
6.
Conclusion
Last Updated: Mar 27, 2024
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Introduction to Computer Network Models

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computer network models

Introduction

A computer network comprises software and hardware that allows one device to communicate and receive data from another. Hardware specifies the set of instructions that utilizes the hardware equipment for data transmission, while software defines the set of instructions that uses the hardware equipment for data transmission. A basic data transfer entails numerous steps over several levels of a computer network. We will go through computer network models in-depth to understand how data is transported and received at the computer level.

Let's talk about the layers that make up a computer model before going into the computer network models. Let's start with a fundamental understanding of the layers involved in data transfer.

Layered Architecture

The major goal of having several layers in a computer network architecture is to break down transmitting and receiving data into smaller, more manageable activities. Each lower layer contributes to the top layer, resulting in a comprehensive collection of services for managing communications and running applications. These levels are interconnected, with each layer providing and receiving data from its immediate upper and lower layers. Dividing a model into layers simplifies the structure, making it easier to see a problem if it arises. A Computer Network model is made up of three primary componentsA sender, A recipient, and A carrier.

It offers modularity and explicit interfaces, allowing subsystems to communicate. It maintains layer independence by offering services from a lower to a higher layer without specifying how they are implemented. Any changes made to one layer will not affect the other levels. From network to network, each layer's levels, functions, and contents will vary. The objective of each layer, on the other hand, is to deliver a service from a lower to a higher layer while masking the specifics of how the services are performed from the layers.

Core Components of the Layered Architecture

The core components of the layered architecture are services, protocols, and interfaces.

  1. Service: It is a collection of activities delivered to a higher layer.
  2. Protocol: It is a collection of rules that a layer follows while exchanging data with a peer entity. These guidelines primarily address the contents and sequence of the messages used.
  3. Interface: This is the method through which information is passed from one layer to the next.
    Layer n on one computer will communicate with layer n on another machine in a layer n architecture. The rules employed in the dialogue are known as a layer-n protocol.

 

Read more about Layered Architecture

Let's look at a five-layered architecture as an example.

example img of five-layered architecture

 

In a layered architecture: 

  • No data is transmitted from layer n of one machine to layer n of another. Instead, each layer passes data to the one right below it until the lowest layer is reached. 
  • True communication occurs in the physical medium, which is found below the layer 
  • Unmanageable jobs are separated into multiple tiny and manageable tasks in a layered architecture.
  • Data is sent from the top layer to the lower layer through an interface. The most fundamental information is carried between layers in a layered design, which produces a straightforward interface. It also ensures that implementing another layer may easily replace the implementation of one layer.
  • Network architecture is a collection of these layers and protocols.
     

Also see, Message Switching in Computer Networks and Basic Networking Commands

Advantages of Layered Architecture

  • The divide-and-conquer method breaks large tasks into smaller, more manageable ones during the design phase. In a word, we can say that this strategy reduces the complexity of the design.
  • The modularity of layered architecture is greater. Modularity provides layer independence, making it easier to understand and use.
  • It maintains layer independence, allowing one layer's implementation to be altered without impacting other layers.
  • Each layer of the layered architecture may be researched and tested individually.

Disadvantages of Layered Architecture

There are some disadvantages to using a layered architecture:

  • Complexity: Layered architecture can increase the complexity of the software due to the additional layers and their interactions. It can also make it harder to understand the overall design and organization of the application.
  • Performance Overhead: Each layer adds a level of abstraction and indirection, which can result in performance overhead. The communication between layers can also slow down the application if not optimized properly.
  • Maintenance Costs: Maintaining a large and complex architecture can be difficult and time-consuming, especially if changes need to be made to multiple layers.
  • Rigidity: The strict separation of responsibilities in a layered architecture can make it difficult to adapt to changing requirements and can lead to a rigid design that is hard to modify.
  • Over-engineering: It's possible to create too many layers, which can lead to over-engineering and unnecessary complexity. This can make the software harder to maintain and understand.
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OSI Model

The OSI (Open Systems Interconnection) model is a seven-layer framework used to describe the flow of information between different network systems. Each layer has a specific function and is responsible for specific aspects of communication. The layers are:

  • Physical: This layer deals with the physical components of the network, such as cables and network devices.
  • Data Link: This layer manages the transfer of data between devices on the same network segment.
  • Network: This layer routes data from one network to another.
  • Transport: This layer ensures reliable delivery of data between endpoints.
  • Session: This layer establishes and manages sessions between applications.
  • Presentation: This layer formats and encrypts data for the application layer.
  • Application: This layer provides the interface between the network and the end-user applications.

Advantages of OSI Model

The advantages of OSI Models are: 

  • Modularity: Divides network communication into seven separate layers, each with a specific function, making it easier to understand and manage.
  • Scalability: Offers a flexible framework that can be adapted to different network sizes and configurations.
  • Improved Troubleshooting: Facilitates the identification and resolution of network issues by breaking down communication into separate layers.
  • Improved Security: Enables the implementation of security measures at different layers, enhancing the overall security of the network.
  • Enhanced Interoperability: Allows for the integration of different network systems and technologies, promoting interoperability and improving communication.

Also see,  Personal Area Network

Disadvantages of OSI Model

The OSI (Open Systems Interconnection) model is a widely accepted standard for network communication, but it also has some disadvantages:

  • Complexity: The OSI model can be complex and difficult to understand, especially for those without a technical background.
  • Implementation Difficulty: Implementing the OSI model in practice can be challenging, especially in large, complex networks.
  • Lack of Flexibility: The strict separation of functions into separate layers can limit the flexibility of network design and implementation.
  • Overhead: The additional layers and processes defined by the OSI model can result in performance overhead, particularly in large networks.
  • Implementation Inconsistencies: The implementation of the OSI model can vary between different vendors, leading to inconsistencies and compatibility issues.
  • Inflexibility: The strict separation of functions into separate layers can make it difficult to adapt to changing network requirements.

 

Read more about - OSI Model and What are payloads

TCP/IP Model

The TCP/IP model is the standard communication protocol for transmitting data over the internet. The TCP/IP (Transmission Control Protocol/Internet Protocol) model is widely used for communication on the internet and other computer networks. 
It consists of 4 layers:

  • Link Layer- The Link Layer deals with transmitting data over physical connections.
  • Internet Layer - The Internet Layer routes data packets between networks.
  • Transport Layer - The Transport Layer ensures reliable transmission of data.
  • Application Layer - The Application Layer provides interfaces for various applications to communicate using the underlying transport protocols.

You can read related articles such as Congestion Control in Computer Networks .

Advantages of TCP/IP Model

The TCP/IP (Transmission Control Protocol/Internet Protocol) model is widely used for communication on the internet and other computer networks. Some of the advantages of the TCP/IP model include the following:

  • Wide Adoption: TCP/IP is the foundation of the internet and is widely used in a variety of networks and communication systems.
  • Simplicity: The TCP/IP model is relatively simple compared to other network models, making it easier to understand and implement.
  • Scalability: TCP/IP is designed to be scalable and can accommodate growth and changes in network size and complexity.
  • Interoperability: TCP/IP is designed to be flexible and interoperable, allowing different networks and systems to communicate with each other.
  • Robustness: TCP/IP is designed to be robust and reliable, ensuring the delivery of data even in the presence of network errors and failures.
  • Flexibility: The TCP/IP model is flexible and allows for the integration of new technologies and applications into existing networks.

Disadvantages of TCP/IP Model

The TCP/IP model has several disadvantages:

  • Complexity: The TCP/IP model has a complex structure with multiple layers, protocols, and standards, making it difficult for novice users to understand and implement.
  • Security: Although it provides some security measures, it is still vulnerable to attacks such as hacking, malware, and denial-of-service (DoS) attacks.
  • Scalability: As the number of internet-connected devices increases, the TCP/IP model may become less scalable and unable to accommodate the growing demands placed on it.
  • Performance: The TCP/IP model's performance can be affected by network congestion, outdated protocols, and slow transmission speeds.
  • Flexibility: The TCP/IP model is not very flexible, and changing or updating protocols can cause compatibility issues with existing systems.
     

Read more about TCP/IP Model

Frequently Asked Questions

What are the 3 types of network models?

Network models include Peer-to-Peer (P2P), where devices communicate equally, Client-Server with dedicated servers serving multiple clients efficiently, and Hybrid networks combining P2P and client-server aspects for flexibility and scalability in network design and management.

Why use a network model?

Network models are used to design and manage communication structures efficiently, ensuring data transmission, security, and resource optimization.

Is TCP a session layer?

No, TCP (Transmission Control Protocol) is not a session layer protocol. It operates at the transport layer of the OSI model, responsible for reliable data transmission and error recovery.

Explain what the TCP/IP Reference Model is.

It is a compressed version of the OSI model with just four levels. It was created in the 1980s by the US Department of Defense (DoD). The name of this architecture is derived from the employment of two common protocols, TCP (Transmission Control Protocol) and IP (Internet Protocol) (Internet Protocol).

Conclusion

This article discussed about the layers that make up a computer model along with the computer network models which is the main crux of this article. Also we studied about the core components of the layered architecture, its advantages in detail.

Recommended Readings:

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