Basics of Computer Networks
A computer network is a collection of computers and other devices interconnected by communication channels that allow sharing of resources and information. Here are some key concepts:
Types of Networks:
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Local Area Network (LAN): Covers a small geographic area, like a home or office. It’s ideal for sharing resources like printers and files.
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Wide Area Network (WAN): Spans a large geographic area, like cities or countries. The internet is the largest WAN.
- Metropolitan Area Network (MAN): Larger than a LAN but smaller than a WAN, covering a city or large campus.
- Personal Area Network (PAN): Used for communication among devices close to one person, like Bluetooth connections between a smartphone and headphones.
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Network Topologies:
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Star Topology: All devices are connected to a central hub. If the hub fails, the entire network goes down.
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Bus Topology: All devices share a common communication line. It’s inexpensive but can be slow and prone to collisions.
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Ring Topology: Devices are connected in a circular fashion. Data travels in one direction, and each device acts as a repeater.
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Mesh Topology: Devices are interconnected, with multiple paths for data. It’s very reliable but can be expensive.
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Network Protocols:
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TCP/IP: The foundational protocol of the internet, responsible for data transmission and addressing.
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HTTP/HTTPS: Used for accessing web pages. HTTPS is the secure version.
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FTP: Protocol for transferring files between computers.
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SMTP: Protocol for sending emails.
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DNS: Translates domain names to IP addresses.
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Network Devices:
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Router: Connects different networks and directs data packets between them.
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Switch: Connects devices within a single network and uses MAC addresses to forward data to the correct destination.
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Modem: Converts digital data to analog signals for transmission over phone lines or cable.
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Firewall: Security device that monitors and controls incoming and outgoing network traffic.
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Wireless Networks:
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Wi-Fi: Common wireless network technology for connecting devices within a LAN.
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Bluetooth: Short-range wireless technology for connecting personal devices.
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Cellular Networks: Used for mobile phone communication, including 3G, 4G, and 5G technologies.
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