Computer Network:

A computer network refers to a collection of computers or devices that are linked together to facilitate data transfer and the exchange of information.
In the field of computing, the term "network" is used to describe the interconnection of two or more devices using various means such as cables, signals, waves, or other methods, with the primary objective of transmitting data, sharing information, resources, and services

Importance of Computer Network:

Sharing of Resources: Networking enables the availability and accessibility of resources to multiple users, regardless of the physical location of the resource or the user. This promotes efficient utilization of resources, simplifies maintenance, and reduces costs.
Sharing of Information: Alongside the sharing of physical resources, computer networking facilitates the exchange of information. By connecting computers located in different physical locations, information stored on networked computers becomes accessible to other computers on the network.
Communication Medium: Networking plays a crucial role in facilitating the transmission of electronic mail (email) messages globally. Users can send and receive data in various formats, such as text, audio, video, and images, via email, enabling faster and cost-effective online communication. Networking also enables video conferencing, allowing individuals in distant locations to hold meetings where they can hear and see each other in real-time.
Centralized Administration and Support: Networking involves the central management and control of all computers and components through a server. This allows for the automatic dissemination of rules, security measures, and other configurations to all clients. Additionally, networking simplifies administration and support tasks by enabling them to be performed from a single location. The network administrator can carry out administrative functions on any computer within the network, with the necessary updates being initially implemented on the server.
Faster and Cost-Effective Communication: The interconnected nature of computers in a network enables fast and cost-effective communication. Messages can be swiftly and inexpensively transmitted between computers. This enables efficient long-distance communication, ultimately saving time.
Backup and Support: Networked computers can be utilized for backing up critical data. In situations where continuous computer availability is required, another computer within the network can take over in the event of a failure.

Advantages of Networking:

Connectivity and Communication: Networking enables the connection and communication between computers and devices.
Data Sharing: Networking facilitates the sharing of data and information between connected computers.
Hardware Sharing: Networking allows for the sharing of hardware resources, such as printers or scanners, among connected devices.
Internet Access: Networking provides the capability to access the internet, enabling users to browse websites, access online services, and communicate globally.
Internet Access Sharing: Networking enables multiple devices to share a single internet connection.
Data Security and Management: Networking involves implementing measures to ensure data security and efficient data management within the network.
Performance Enhancement and Balancing: Networking can enhance performance by optimizing data transmission and balancing the load across network devices.
Entertainment: Networking allows for the sharing and streaming of multimedia content, facilitating entertainment options such as online gaming, streaming movies, or music.

Disadvantages of Computer Networking:

Initial setup cost can be high: While computer networks are generally considered cost-effective once they are up and running, the initial setup cost can still be significant, particularly based on the number of computers to be connected. Expenses may arise from the need for devices like routers, switches, hubs, as well as network interface cards (NICs) for workstations if they are not already built-in.
Expense involved: The formation of a computer network requires additional devices and resources like network interface cards (NICs), hubs, cables, modems, which contribute to the overall cost of networking.
Data security concerns: Despite the server's management and control over the networked computers, data transmitted during communication can be susceptible to hacking and unauthorized access, leading to data corruption and leaks within the network.
Requirement for specialized technical knowledge: Operating a networking system necessitates skilled personnel with specific technical expertise, which can be a challenge.
Increased vulnerability to computer viruses and malware: Networking environments can be more prone to computer viruses and malware, potentially resulting in corrupt files. Regular system checks and file inspections by network administrators are essential to mitigate such risks.

Types of Computer Networks:

On the basis of geographical area:

On the basis of User:

INTERNET
INTRANET
EXTRANET

On the basis of Architecture:

Client/Server(C2S)
Peer to Peer(P2P)
Value Added Network(VAN)

On the basis of Topology:

BUS
STAR
RING
MESH

On the basis of geographical area:

Local Area Network (LAN):

The network expands across different areas, including rooms, floors, buildings, and organizations.
The network coverage extends within a radius of approximately 1 kilometer.
Various types of media can be employed for network connectivity, such as twisted pair cables, coaxial cables, wireless radio modems, and more.
Switches are commonly used as the primary connecting devices in the network.
Both peer-to-peer and client/server technologies can be utilized in the network.
The network is characterized by simplicity and cost-effectiveness.
The star topology is predominantly employed in network configurations.
The network offers significantly faster data transmission compared to other types of networks.

Metropolitan Area Network (MAN):

Metropolitan Area Networks (MANs) connect multiple local area networks within a metropolitan area, typically spanning around a 50-mile radius.
An example of a MAN is a cable TV network.
MANs commonly utilize the bus topology, and coaxial cables are typically employed for connectivity.
The speed of a MAN is comparable to that of a local area network (LAN).
MANs are private networks, designed to serve a specific geographical area.
MANs tend to be costlier to implement and maintain compared to LANs.

Wide Area Network(WAN):

Wide Area Networks (WANs) encompass extensive geographical areas, including large cities, metropolitan areas, entire countries, and even multiple countries or continents.
WANs are essentially networks of networks, commonly referred to as the internet.
Various topologies can be employed in WAN configurations.
Wireless technology and fiber optic cables are commonly used in WAN connections.
WANs do not have a single owner or controller, as they are decentralized networks.
Compared to local area networks (LANs) and metropolitan area networks (MANs), WANs tend to have slower speeds and higher costs.
Different protocols, such as TCP/IP, HTTP, FTP, and others, are utilized in WAN communications.

On the basis of Architecture:

Peer to Peer (P2P):

Each computer in the network is directly connected to each other or through a connecting device.
The interconnected computers are referred to as peer computers.
The connected computers can function both as clients and servers.
Peer-to-peer networks are straightforward to set up and do not require advanced technical skills.
Twisted pair cables are commonly used for connectivity in this type of network.
Remembering usernames and passwords can be challenging in a peer-to-peer network.
Privacy and security may be lacking in peer-to-peer networks.

Characteristics:

The installation and configuration of computers in a peer-to-peer network are easy to perform.
Unlike a server-client architecture where the server shares all the resources and contents, in a peer-to-peer network, all peers share resources and contents with each other.
Peer-to-peer networks are more reliable as there is no central dependency. The failure of one peer does not impact the functioning of other peers. In contrast, in a client-server network, if the server goes down, the entire network is affected.
There is no requirement for a full-time system administrator in a peer-to-peer network. Each user acts as the administrator of their own machine and can control their shared resources.
The overall cost of building and maintaining a peer-to-peer network is relatively low.
Peer-to-peer technology is used in torrents, enabling the sharing of files among users.

Advantages:

Installation and configuration are straightforward.
Users have control over their own shared resources.
Operating costs are low.
No additional hardware or software is required apart from a suitable operating system.
Each computer in the network can function as a server, eliminating the need for a dedicated server.
Failures in one computer do not impact the functioning of all other computers.
Reduced expenses.
Faster configuration and implementation process.
No need for dedicated administrators.

Disadvantages:

Network security measures are applied to individual resources one at a time.
Each machine needs to be backed up separately to ensure the protection of shared data.
There is no centralized organizational structure for locating or controlling access to data.
Without a server, there is no control over access to data.
Easy remote access can potentially expose systems to security breaches.

Client Server Network:

In a network, computers are connected, with one specific computer known as the server and the rest as clients.
The server is a high-end computer that provides services in response to client requests.
Clients are computers that request services and typically function as workstations.
Twisted pair cables are commonly used for connectivity.
The network follows a client-server architecture, where the server is responsible for providing services and the clients make requests for those services.
The network system can be expensive to implement.
Skilled personnel are required to operate the network.
Resources are centrally stored in the network.
Privacy is safeguarded, and a robust security system is in place.
Unauthorized users are prevented from accessing the network resources.
Resources are available online at all times.
Usernames and passwords are easy to remember in the network system.

Value Added Network:

It is a privately owned network accessible to authorized users.
The network enables Electronic Data Interchange (EDI) and various other services.
It serves as a middleman between business partners who exchange standardized information.
The network ensures secure and protected data exchange.
Additional services such as EDI translation, message encryption, secure email, management reporting, error detection and correction, protocol conversion, and more are now available to customers.

On the basis of Topology:

Bus Topology:

Bus topology is a network configuration where devices are connected to a central cable known as the "bus."
Devices in this topology share the same communication medium, enabling bidirectional data transmission.
Each device on the bus receives transmitted data and checks if it is the intended recipient based on the data packet's address.
Bus topology is a straightforward and cost-effective solution to implement.
Compared to other topologies, it requires less cabling as all devices connect to a single cable.
However, if the main bus cable fails, the entire network may experience disruptions.
Adding or removing devices from the bus can momentarily interrupt network communication.
Bus topology is best suited for small networks with a limited number of devices.
It is commonly utilized in local area networks (LANs) and frequently seen in Ethernet networks.

Star Topology:

Star topology is a network setup where all devices connect to a central hub, such as a switch or a hub.
Each device has its own dedicated connection to the central hub.
Data is transmitted by sending it to the hub, which then forwards it to the intended recipient.
The hub serves as a central control point for communication between devices.
If one device experiences a failure or issue, it does not impact the functioning of other devices in the network.
Adding or removing devices in a star topology does not disrupt the overall network's operation.
Troubleshooting and maintenance are simplified in a star topology, as each device's connection can be easily examined.
However, star topology requires more cabling compared to other topologies, as each device requires a separate connection to the central hub.
It offers scalability, making it suitable for networks of varying sizes, from small to large.
Star topology is commonly used in Ethernet networks and is commonly found in home and office environments.

Ring Topology:

Ring topology
is a network setup where devices are connected in a circular loop.
Each device in the ring connects to two neighboring devices, creating a continuous ring.
Data travels in one direction around the ring, passing through each device until it reaches its destination.
Devices check if they are the intended recipients and forward the data accordingly.
Token passing is often used in ring topology to control data transmission, where a special token circulates the ring.
If a device or connection fails in the ring, it can disrupt the entire network.
Adding or removing devices can cause disruptions and require reconfiguration of the ring.
Ring topology is less common in modern networks but is still used in specific applications like token ring networks.
It provides equal access to all devices and can be efficient for certain data transmission scenarios.
Troubleshooting and maintenance can be more challenging due to the reliance on a continuous ring.
Ring topology is not as scalable as other topologies and may not be suitable for large networks.

Mesh Topology:

Mesh topology is a network configuration where each device is directly connected to every other device in the network.
This fully interconnected network allows for direct data transmission between any two devices without relying on intermediaries.
The mesh topology offers high redundancy and fault tolerance as multiple paths are available for data transmission.
In the event of a connection or device failure, data can still be routed through alternative paths.
Mesh topology is highly scalable, allowing for the easy addition of new devices without disrupting existing connections.
It provides reliable and high-performance networking, particularly suitable for large networks with heavy traffic.
However, implementing a mesh topology requires a significant amount of cabling, which can be costly.
Managing and configuring a mesh network can be complex due to the numerous connections involved.
Mesh topology is commonly deployed in critical infrastructure settings like telecommunications networks and large-scale data centers, where reliability and fault tolerance are paramount.

Computer System

Computer Network