In this tutorial you are going to learn about Protocol Hierarchies in Computer Networks.
Introduction
A Protocol Hierarchy in a computer network is a set of rules and conventions that govern the communication between different devices and systems. These protocols are organised into layers, with each layer building upon the one below it to provide a set of services and functions. The most commonly used protocol hierarchy in computer networks is the OSI (Open Systems Interconnection) model.
The OSI model consists of seven layers, with each layer responsible for a specific aspect of network communication. Starting from the bottom, the seven layers are:
- Physical: This layer is responsible for the physical transmission of data over the network, including the types of cables and connectors used, as well as the signalling and modulation methods.
- Data Link: This layer is responsible for providing reliable data transfer over a single link between two devices. It defines the format and organization of data packets, as well as error detection and correction methods.
- Network: This layer is responsible for routing data packets between different devices on a network. It defines the methods used to identify different devices and networks, and the algorithms used to determine the best route for a given packet.
- Transport: This layer is responsible for ensuring that data is delivered reliably and in the correct order. It handles flow control and error recovery, and defines the methods used to establish and tear down connections between devices.
- Session: This layer is responsible for establishing, maintaining and terminating sessions between different devices on the network. It is responsible for handling authentication and security.
- Presentation: This layer is responsible for translating between different data formats and encoding methods, such as encryption and compression. It is responsible for handling issues related to data representation and syntax.
- Application: This layer is responsible for providing services to the end-user. It provides the interface between the application and the network and defines the communication methods used by different applications to access the network.
The OSI model provides a framework for understanding how different protocols in a network interact and how they are layered on top of each other. It also provides a useful way of identifying and solving problems in a network, by making it possible to pinpoint issues at the specific layer where they are occurring.
However, the OSI model has its own limitations, in practice, many protocols span across multiple layers. The most widely used protocol stack for the Internet, the TCP/IP stack, for example, has only 4 layers, Physical, Network Access, Internet, and Application layers. Additionally, the OSI model is mostly used as a reference model and it is not necessarily followed strictly in the design of modern networks.
Advantages
- Simplifies network communication: Protocol hierarchies provide a structured way of organising the communication process between devices and systems, making it easier to understand and troubleshoot.
- Increases flexibility: Protocol hierarchies provide a logical separation of functions, enabling each layer to perform its function independently from the others. This allows for flexibility and ease of modification.
- Improves interoperability: Protocol hierarchies enable vendors to implement their own solutions for each layer, as long as they conform to the standard of that specific layer, This increases interoperability between different vendors' solutions.
- Facilitates standardisation: Protocol hierarchies are often based on standards, which allows for a common understanding of how the protocols should be used and how they interact with each other.
Disadvantages
- Complexity: Protocol hierarchies can be complex, as they require a deep understanding of the different layers and how they interact.
- Rigidity: Protocol hierarchies can be rigid, and they may not adapt well to new technologies or changing requirements.
- Limited by standards: Protocol hierarchies are often based on standards, which can limit innovation and the introduction of new technologies.
- Can be costly: Implementing and maintaining a protocol hierarchy can be costly, as it requires specialized knowledge and equipment.
Protocol hierarchies in computer networks play a crucial role in facilitating communication between devices and systems. The OSI model is the most widely used protocol hierarchy and provides a framework for understanding how different protocols interact and how they are layered on top of each other. However, it is important to note that in practice, many protocols span across multiple layers and the OSI model is not necessarily followed strictly in the design of modern networks. Additionally, the popular Internet protocol stack, TCP/IP, only has four layers. Understanding the different layers in the protocol hierarchy and how they interact is essential for designing, troubleshooting and maintaining modern computer networks.
This tutorial on Protocol Hierarchies in Computer Networks is contributed by Rajnish Kumar. If you like TheCode11, then do follow us on Facebook, Twitter and Instagram.
