Fundamentals of Networking - Physical Topology

Physical Topology

• Represents the physical layout of a network, including computers, cables, and components.
• Alternative terms: Physical layout, Design, Diagram, Map.
• Composed of links connecting multiple devices; link structures form a topology.

Logical Topology

• Bound to network protocols that define data movement across the network.

Impact of Topology

• Affects network capabilities, equipment requirements, scalability, and management.

Basic Topologies

• Bus, Star, Ring, Mesh, and Hybrid.

Bus Topology

• Uses a single long cable as a backbone connecting all devices.
• Advantages: Easy connections and lower cable usage.
• Disadvantages: Network failure if the main cable breaks, requires terminators, troubleshooting issues.

Star Topology

• Each device connects to a central controller or concentrator.
• Advantages: Robust, easy fault isolation, cheaper than mesh.
• Disadvantages: Single point of failure, requires more cable than bus topology.

Ring Topology

• Devices connect to two neighbors, allowing signal transmission in one direction.
• Utilizes repeaters in each device to maintain signal strength.

Mesh Topology

• Each device has a direct point-to-point link with every other device.
• Advantages: No traffic problems, robust, enhanced privacy, easy fault identification.
• Disadvantages: High cabling and port requirements make it more expensive.

Hybrid Topology

• Combines elements from different topologies, e.g., star and bus.

Internetworking

• Interconnection among various networks, known collectively as the internet.
• Variants include Intranet (controlled by a single entity), Extranet (open to external parties), and Internet (global network of networks).

Mode of Transmission

• Refers to how signals flow between devices:
  • Simplex: One-way communication (e.g., TV).
  • Half-duplex: Two-way but not simultaneously (e.g., walkie-talkies).
  • Full-duplex: Two-way communication at the same time (e.g., telephones).

Transmission Media

• Guided or unguided mediums transmit data via electromagnetic waves.
• Success depends on signal quality and transmission medium characteristics.

Analog vs. Digital Data Representation

• Analog data: Continuous values (e.g., audio).
• Digital data: Discrete values (e.g., text).
• Signals can be analog (continuous) or digital (discrete).

Signals Characteristics

• Amplitude: Signal strength at a specific point.
• Frequency: Collection of all component frequencies.
• Bandwidth: Width of frequency spectrum.

Transmission Impairments

• Signals may degrade during transmission, leading to analog quality loss or digital bit errors.
• Common causes: Attenuation, delay distortion, and noise.
• Solutions: Amplifiers for analog signals, repeaters for digital signals.

Attenuation

• Signal strength diminishes over distance; depends on medium.
• Essential for received signal to be detectable and higher than noise levels.

Delay Distortion

• Occurs in guided media where signal propagation speeds vary with frequency.

Noise Types

• Thermal noise, crosstalk, impulse noise, and inter-modulation noise impact signal clarity.

Signal vs. Data

• Analog signals can encode both analog and digital data; digital signals primarily encode digital data.

Pulse Code Modulation (PCM)

• Converts analog signals into digital form by sampling, quantizing, and encoding.

Modulation Techniques

• Used for effective transmission of high-frequency analog data over shared mediums:
  • Amplitude Modulation (AM)
  • Frequency Modulation (FM)
  • Phase Modulation (PM)

Multiplexing

• Combines multiple signals into one over a shared medium, optimizing resource use.
• Demultiplexing retrieves original signals on the receiving side.
• Basic types:
  • Time-Division Multiplexing (TDM) for digital signals.
  • Frequency-Division Multiplexing (FDM) for analog signals.

Explore the concepts of physical topology in networking, focusing on the arrangement of devices and connections. This quiz delves into the definitions, characteristics, and types of physical layouts in a network. Test your understanding of how these components work together to form a functional network.