Computer Networks Lecture Notes

A computer network is a collection of computers or other devices connected together, enabling communication and resource sharing.

End-user devices are computers or devices directly used by individuals for tasks like browsing, working, or gaming.

Intermediate network devices facilitate communication between end-user devices and the network, often managing data flow and security.

A repeater regenerates or amplifies signals to maintain signal strength over longer distances, extending network reach.

A hub is a simple network device that broadcasts data to all connected devices, making it less efficient for larger networks.

A bridge acts like a traffic policeman, forwarding data selectively between different segments, improving network performance.

A switch, smarter than a hub, forwards data directly to the intended recipient, reducing network congestion.

A router connects different networks (LANs, WANs, etc.), directing data packets efficiently to their destination based on network addresses.

A modem converts digital data from your computer into an analog signal for transmission over phone lines and back again, allowing communication over phone networks.

A network interface card (NIC) is a physical card inserted into a computer that provides a connection point for network media, enabling the computer to join a network.

A proxy server acts as an intermediary between your computer and the internet, enhancing security and managing internet access.

Copper cable utilizes electrical pulses to transmit data, a common but less efficient option compared to newer technologies.

Fiber-optic cable transmits data using light pulses, offering high bandwidth and speed, ideal for long-distance communication.

Wireless communication transmits data using electromagnetic waves, including radio waves, microwaves, and infrared, offering flexibility and convenience.

Bandwidth represents the data transmission capacity of a network connection, measured in bits per second.

An intranet refers to a private network exclusively for an organization's members, often containing internal information and resources.

An extranet provides controlled access to an organization's network for external parties, such as suppliers or partners.

The Internet represents a global network of interconnected networks, enabling worldwide communication and access to information.

DSL (Digital Subscriber Line) provides a dedicated, always-on high-speed internet connection over existing phone lines, suitable for home or small office use.

Cable internet utilizes the same coaxial cables as cable TV to provide a high-speed internet connection, often offering fast speeds.

Dial-up internet uses a traditional modem and phone line to connect, offering low speed and limited availability.

Satellite internet uses satellites to beam internet signals, providing an option for remote areas without cable or DSL availability.

Cellular internet uses a mobile phone network, providing internet access via a smartphone or mobile device.

A network protocol is a set of rules and standards that define how data is formatted, exchanged, and interpreted across a network.

TCP/IP (Transmission Control Protocol/Internet Protocol) is a widely used network protocol suite that enables data exchange over the internet and other networks.

A data packet is a small unit of data encapsulated with information about its origin and destination, used for data transmission across networks.

Network security measures protect network infrastructure and data from unauthorized access, cyber threats, and potential breaches.

A firewall is a network security device that acts as a barrier between your network and the outside world, filtering incoming and outgoing traffic.

An intrusion detection system (IDS) analyzes network traffic for suspicious patterns and potential threats, alerting administrators to security breaches.

A VPN (Virtual Private Network) creates an encrypted tunnel over a public network, enhancing security and privacy for data transmission.