A computer network is a group of connected devices that communicate with each other to share data and resources. It enables efficient communication and supports services like email, file sharing, and internet access.
- Nodes are devices such as computers, mobiles, or printers that exchange data.
- Routers and switches control and direct the flow of information.
- Transmission media carries data between devices.
- Wired media includes Ethernet and optical fiber cables.
- Wireless media includes Wi-Fi, Bluetooth, and infrared.
Working
A computer network operates by enabling devices to communicate and exchange data using a shared communication system. Each device in the network follows predefined rules to ensure that data is transmitted accurately, efficiently, and securely.
- A network consists of nodes such as computers, servers, routers, and switches that send or receive data.
- These nodes are connected through links, which may be wired (cables, optical fiber) or wireless (Wi-Fi, radio signals).
- When data is sent, it is broken into small packets and transmitted across the network.
- Protocols define how data packets are formatted, transmitted, received, and acknowledged.
- Each device is identified by a unique IP address, which ensures data reaches the correct destination.
- Network devices like switches and routers forward data packets along the best available path.
- Security mechanisms, such as firewalls, monitor traffic and allow or block data based on security rules.
Types of Computer Network Architecture
Computer Network falls under these broad Categories:
- Client-Server Architecture: Client-Server Architecture is a type of Computer Network Architecture in which Nodes can be Servers or Clients. Here, the server node can manage the Client Node Behaviour.
- Peer-to-Peer Architecture: In P2P (Peer-to-Peer) Architecture, there is not any concept of a Central Server. Each device is free for working as either client or server.
Network Devices
1. Router
A Router is a networking device that connects multiple networks and directs data between them.
- Connects local networks to the internet
- Determines the best path for data packets
- Uses IP addresses to forward data correctly
2. Switch
A Switch connects devices within the same network and manages internal data communication.
- Connects computers, printers, and servers
- Sends data only to the intended device
- Improves network efficiency and performance
3. Hub
A Hub is a basic device that connects multiple devices in a network.
- Broadcasts data to all connected devices
- Does not filter or manage traffic
- Less secure and less efficient than a switch
4. Bridge
A Bridge connects two network segments and filters traffic between them.
- Reduces unnecessary data transmission
- Improves network performance
- Works using MAC addresses
5. Gateway
A Gateway connects two different networks that use different protocols.
- Translates data between different systems
- Enables communication between dissimilar networks
- Commonly used to connect private networks to external networks
6. Access Point (AP)
An Access Point provides wireless connectivity to devices in a network.
- Extends a wired network into Wi-Fi
- Allows mobile devices to connect wirelessly
- Improves network coverage area
7. Modem
A Modem converts digital data into signals suitable for transmission and vice versa.
- Connects a home or office network to the ISP
- Converts digital signals to analog and back
- Enables internet access
8. Firewall
A Firewall is a security device that monitors and controls network traffic.
- Blocks unauthorized access
- Filters incoming and outgoing data
- Protects networks from cyber threats
Goals and Uses of Computer Networks
- Communication and Collaboration: Enable communication through email, messaging, video conferencing, and collaborative platforms.
- Resource Sharing: Allow multiple users to share hardware, software, and data resources efficiently.
- Data Access and Sharing: Provide easy access to stored data and allow information exchange between users and systems.
- Internet and Cloud Access: Enable access to the Internet, online services, and cloud-based applications.
- Cost Efficiency: Reduce operational and infrastructure costs through shared resources and centralized systems.
- Reliability and Availability: Improve system reliability using backup paths and fault-tolerant mechanisms.
- Scalability and Growth: Support easy expansion by adding new devices and services as demand increases.
- Security and Control: Protect data and network resources using authentication, access control, and monitoring.