Computer Networks: Classifications & Media

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Questions and Answers

Which of these are types of computer networks?

Local Area Networks

Wide Area Networks

Metropolitan Area Network

All of the above (correct)

What is a Local Area Network (LAN)?

A LAN is a small, single-site network connecting devices within a limited geographical area, managed by a single entity.

A wide area network (WAN) spans a small geographical area.

False

What device connects LANs to a WAN?

Router Signup and view all the answers

What is a Personal Area Network (PAN) typically used for?

Connecting personal electronic devices Signup and view all the answers

What is a key feature of a Metropolitan Area Network (MAN)?

Interconnects LANs within a city Signup and view all the answers

A ______ is used to modulate and demodulate data signals.

Modem Signup and view all the answers

What is the primary use of fiber optic cables?

To transmit light signals for high-speed data transmission. Signup and view all the answers

In a Local Area Network, resources such as ______ can be shared between computers.

hardware and software Signup and view all the answers

Which of the following is a characteristic of wired connections?

Lower susceptibility to interference Signup and view all the answers

Which layers of the OSI model do modems operate at?

Data Link Layer (Layer 2) Signup and view all the answers

What is the primary function of a modem?

To encode digital information onto an analog carrier signal and decode it back to digital. Signup and view all the answers

How does a Network Interface Card (NIC) connect to a network?

Physically via cables or wires Signup and view all the answers

A hub operates at the data link layer of the OSI model.

False Signup and view all the answers

What is the main purpose of a repeater?

To receive, clean, and retransmit electronic signals at a higher power level. Signup and view all the answers

Which of the following devices connects multiple network segments and operates at the data link layer?

Switch Signup and view all the answers

What defines the main function of a router?

To connect two different networks and forward data packets based on IP addresses. Signup and view all the answers

A gateway can function as a router but typically offers more functionalities.

True Signup and view all the answers

What is the primary purpose of a firewall?

To monitor incoming and outgoing network traffic and enforce security rules. Signup and view all the answers

What role does a server play in a network?

Provides services and resources to client computers Signup and view all the answers

Study Notes

Network Classifications

Computer networks are classified into categories based on purpose and geographical area.
Two primary categories: Local Area Networks (LAN) and Wide Area Networks (WAN), with other types like PANs, CANs, and SANs.

Local Area Network (LAN)

LAN serves a single site, connecting devices within a small geographical area, typically a few kilometers.
Common in homes, offices, schools, hospitals, and factories, facilitating resource sharing (e.g., printers, software).
Managed by a single individual or organization.
Uses wired (Ethernet cables) or wireless (Wi-Fi) connections for flexibility and mobility.
Enables efficient communication and collaboration among connected devices.

Wide Area Network (WAN)

WAN spans a large geographical area, connecting multiple LANs and remote sites across countries or continents.
Commonly uses routers for connection and often relies on telecommunications or internet service providers (ISPs).
Employs a mix of public and private communication links, such as fiber optics, leased lines, and satellites.
Examples include corporate networks, research institutions, and government entities.
High availability and fault tolerance are ensured through redundant links.

Metropolitan Area Network (MAN)

MAN interconnects users within a specific geographic area, larger than LAN but smaller than WAN (typically a city).
Often uses bridges to link multiple LANs and can provide high-speed internet via local ISPs.
Functions as a middle layer connecting LANs to WANs, offering services like file sharing and internet access.
Examples include networks for educational institutions, government agencies, and corporate entities.

Personal Area Network (PAN)

PAN is a small network designed for personal use, covering an area within an individual's immediate surroundings, like a room.
Connects personal devices such as smartphones, tablets, wearables, via wired (USB) or wireless (Bluetooth, Zigbee) technologies.
Typically, PANs do not connect directly to the internet but can connect to a LAN for internet access.

Transmission Media

Transmission media refers to materials carrying energy waves for data transfer, classified as wired (guided) and wireless (unguided).

Wired Transmission Media

Twisted-Pair Cables: Composed of twisted pairs of copper wires. Varieties include shielded (STP) and unshielded (UTP) cables. UTP is inexpensive and prevalent in offices. STP offers better signal quality due to shielding.
Coaxial Cables: Robust cables with a central conductor surrounded by insulation and shielding. Commonly used in telecommunications, identified by RG numbers (e.g., RG-6).
Fiber Optic Cables: Transmit data as light pulses; faster with less signal loss. Includes single-mode (long distance, high bandwidth) and multimode (shorter distance) fibers.

Wireless Transmission Media

Wireless signals travel through air using electromagnetic waves, eliminating the need for physical connections.
Radio Waves: Cover frequencies from 3 kHz to 1 GHz, suitable for long-distance communication.
Microwaves: Frequencies from 1 to 300 GHz; ideal for unicast communications like cellular and satellite networks.
Infrared: Frequencies from 300 GHz to 400 THz; limited to short-range, line-of-sight communications, preventing interference.

Comparison of Wireless and Physical Media

Wireless offers mobility but has limitations in range and reliability; physical media provides higher data rates and reliability but lacks mobility.

Network Devices

Modem: Modulates and demodulates data signals, connecting devices to WANs and converting digital to analog signals and vice versa. Operates at physical (Layer 1) and data link (Layer 2) OSI layers.
Network Interface Card (NIC): A hardware component enabling device connection to networks, supporting wired or wireless communication. Operates at data link layer (Layer 2).
Repeaters: Receive and amplify electronic signals to extend transmission distances.

Modem vs. NIC

NIC connects devices to LANs; modem connects to WANs (e.g., internet) and handles digital-to-analog signal conversion.### Repeaters
Used to regenerate or amplify signals for long-distance transmission.
Operate at the physical layer of the network to combat signal attenuation and loss.
Receive and clean weak or degraded signals, retransmitting them at a higher power to extend network range.

Hubs

Basic networking device connecting multiple devices via cables, functioning at the physical layer.
Distributes data received at one port to all other ports, leading to collisions in larger networks.
Serves as a central connection point, but is inefficient and less common in modern networks.

Bridges

Networking devices that segment networks to manage traffic and reduce congestion.
Operate at the data link layer, connecting multiple LANs and forwarding data packets.
Examine MAC addresses for forwarding decisions, improving network performance.

Switches

More intelligent than hubs, with capabilities to selectively send data to specific ports.
Operate at the data link layer, using MAC addresses for forwarding data packets.
Offer greater performance and are essential in networks with many devices, commonly used in modern Ethernet.

Switches vs Bridges

Switches provide advanced features over bridges, including higher port density and VLAN support.
Enable improved performance through full-duplex operation and increased scalability.

Routers

Communication devices that connect different networks, forwarding data packets based on IP addresses.
Operate at the network layer, sorting incoming data for the correct destination.
Essential components of the Internet, navigating traffic based on routing decisions.

Gateways

Interface between networks using different protocols, translating data for compatibility.
Can be hardware devices, software applications, or both, connecting local networks to the Internet.
Function like routers but with added protocol translation capabilities.

Firewalls

Network security devices that monitor and control incoming and outgoing traffic based on security rules.
Protect networks from unauthorized access and various threats, acting as barriers between internal networks and the Internet.
Can exist as hardware or software solutions, ensuring proper resource access while blocking unwanted traffic.

Servers

Dedicated computers providing services and resources to client computers on a network.
Handle client requests for shared resources, data storage, and application access.
Critical for managing user queries, hosting content, and facilitating various network tasks.

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Description

This quiz explores the various classifications of computer networks along with the types of transmission media and devices used. Gain a deeper understanding of Local Area Networks and more. Perfect for students in networking courses to test their knowledge.