Understanding how different systems communicate, share resources, and connect is crucial. Our focus will be on understanding the fundamental of OSI (Open Systems Interconnection) model. This conceptual framework is essential for anyone looking to grasp the complexities of network architecture and operations. It serves as a universal language or a blueprint for designing and implementing network protocols, ensuring diverse systems can interoperate seamlessly.
OSI - OPEN SYSTEMS INTERCONNECTION
OSI stands for Open Systems Interconnection. It is a conceptual framework for how application communicate over a network.The OSI was introduced in 1984 by the International Organization of Standard
LAYERS OF OSI MODEL
The layer of an OSI model is provided by a mixture of network card drivers, OS, networking hardware and application transmitting information over a twisted pair, fiber optics or WiFi protocols. There are:
Physical
Data Link
Network
Transport
Session
Presentation
Application
Physical: This encompasses the network cables, router, power lugs, wireless radio frequencies etc. In networking this is the layer that troubleshooting starts.
Data Link: Series of activities takes place in the Data link layer. The Data link layer is where links are set up across physical networks, checks for transmission errors and the packages are bit into dataframes. This consists of two important control point:
Media Access Control (MAC)
Logical Link Control (LLC)
Network: This layer controls the routing of data, check if data has reached its ultimate target. Sends data to correct destination and manages the mapping across logical address and physical address.
Transport: The Transport layer is responsible for data across network connection, where data goes, how fast and how much data is sent. It maybe provided by TCP and UDP, other protocols may provide utility to the layer.
TCP: Transmission Control Protocol
UDP: User Datagram Protocol
Session: The Session layer is where construction, direction and conclusion of connections between devices occurs. This layer is where authentication, redirection and conclusion of network.
Presentation: Presentation layer performs a syntax processing i.e data from one format to another for the end user.
Application: This is the layer most users interact with and it is easy to recognize. It provides network services to the users e.g http. This helps the application layer transmit and receive data from the presentation layer.
TYPES OF COMPUTER NETWORK
A computer network refers to a group of interconnected computing devices that can exchange data and share resources. There can be categorized based on:
Transmission Medium: This can be a wired or wireless network
Protocols: These include Ethernet network, token-ring network, WiFi network, or cellular phone network
Area Cover: Networks can cover large and small area depending on its configuration. There are: NANO, NFC, BAN, PAN, NAN, LAN, WLAN, CAN, MAN, RAN, WAN, IPN, Internet.
| NETWORK (abbrv.) | FULL NAME |
| NFC | Near Field Communication |
| BAN | Body Area Network |
| PAN | Personal Area Network |
| NAN | Near-me Area Network |
| LAN | Local Area Network |
| WLAN | Wireless LAN |
| CAN | Campus/Corporate Area Network |
| MAN | Metropolitan Area Network |
| RAN | Radio Area Network |
| WAN | Wide Area Network |
As we've journeyed through the intricacies of the OSI model, from the tangible connections of the Physical Layer to the abstract rules of the Application Layer, it's clear that this model is more than just a theoretical construct. It is a foundational framework that underpins the design and operation of network systems worldwide. By segmenting the network communication process into seven distinct layers, the OSI model provides a clear structure for understanding, developing, and troubleshooting network technologies.