Computer Networks and Computer Devices

Computer Network

A group of interconnected devices (like computers, servers, and other hardware) that communicate with each other to share data, resources, and services.

Local Area Network (LAN)

Covers a small geographic area, like a home, office, or building.

Wide Area Network (WAN)

Spans a large geographical area, often connecting multiple LANs.

Metropolitan Area Network (MAN)

Covers a city or campus, larger than a LAN but smaller than a WAN.

Personal Area Network (PAN)

Small, short-range network around an individual, like Bluetooth or infrared connections between a phone and a computer.

Wireless Local Area Network (WLAN)

Similar to LAN but uses wireless connections (e.g., Wi-Fi) instead of cables.

Protocols

Rules for communication between devices.

TCP/IP

Transmission Control Protocol/Internet Protocol, the core protocol suite for the internet.

HTTP/HTTPS

Protocols used for accessing the web.

FTP

File Transfer Protocol, used for transferring files.

SMTP

Simple Mail Transfer Protocol, for email transmission.

Bandwidth

The amount of data that can be transferred over a network in a given amount of time.

Latency

The time it takes for data to travel from one point to another in a network.

Network Devices

These are hardware components that allow communication between computers and other devices on a network.

Router

Directs data between different networks, typically between a local network (e.g., your home) and the internet. It finds the best path for data packets to travel.

 Switch

Connects devices within a LAN and forwards data to the intended device. It operates at the Data Link Layer (Layer 2) of the OSI model.

Hub

A basic network device that connects multiple devices on a network but broadcasts data to all ports, not just the intended device.

Modem

Converts digital data from a computer into analog signals for transmission over telephone lines and vice versa. Typically used to connect to the internet.

Access Point (AP)

Extends the range of a wireless network by allowing more devices to connect to the network wirelessly. It connects to a router or switch.

Firewall

Monitors and controls incoming and outgoing network traffic based on predefined security rules. It can be hardware or software-based.

Network Interface Card (NIC)

A hardware component that allows a computer or device to connect to a network. Each NIC has a unique MAC address.

Bridge

Connects two or more LANs, filtering traffic and reducing network congestion. It operates at the Data Link Layer.

Gateway

A device that acts as a "gate" between two networks, often used to connect a private network to the internet. It can translate between different protocols and network architectures.

Proxy Server

Acts as an intermediary between a user and the internet, providing security, anonymity, and caching.

Bus Topology

All devices share a common communication line or bus.

Star Topology

Devices are connected to a central hub or switch.

Ring Topology

Devices are connected in a circular fashion, where each device is connected to two others.

Mesh Topology

Every device is connected to every other device, providing high redundancy.

OSI Model

A conceptual framework used to understand how different networking protocols interact. It has 7 layers.

Physical Layer

Transmits raw data over physical media (cables, radio waves).

Data Link Layer

Handles error detection and flow control over the physical medium.

Network Layer

Routes data between different networks (IP).

Transport Layer

Ensures data is transmitted error-free and in sequence (TCP).

Session Layer

Manages sessions between networked applications.

Presentation Layer

Ensures data is in a usable format (encryption, compression).

Application Layer

Interacts with the end user (HTTP, FTP).

Repeater

Amplifies or regenerates signals to extend the range of a network. It is commonly used in large networks or wireless systems.