Questions and Answers
Which of these are types of computer networks?
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?
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What is a Personal Area Network (PAN) typically used for?
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What is a key feature of a Metropolitan Area Network (MAN)?
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A ______ is used to modulate and demodulate data signals.
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What is the primary use of fiber optic cables?
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In a Local Area Network, resources such as ______ can be shared between computers.
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Which of the following is a characteristic of wired connections?
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Which layers of the OSI model do modems operate at?
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What is the primary function of a modem?
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How does a Network Interface Card (NIC) connect to a network?
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A hub operates at the data link layer of the OSI model.
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What is the main purpose of a repeater?
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Which of the following devices connects multiple network segments and operates at the data link layer?
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What defines the main function of a router?
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A gateway can function as a router but typically offers more functionalities.
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What is the primary purpose of a firewall?
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What role does a server play in a network?
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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.
