Network Topologies Quiz

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Questions and Answers

What is a key disadvantage of bus topology?

Allows private messages between nodes

Failure of the cable results in network failure (correct)

Easy to troubleshoot network issues

Requires a central hub for connections

Which topology allows for a single point of failure due to its structure?

Star topology

Bus topology

Ring topology (correct)

Mesh topology

What is one of the primary advantages of star topology?

Guarantees high data transmission rates

Enables direct connections between all nodes

Supports secure private communications

Requires less cabling and is less expensive (correct)

Which statement best describes the data transmission direction in bus topology?

Data is transmitted in only one direction Signup and view all the answers

How does the ring topology affect message transmission efficiency?

Unnecessary message passing occurs to all nodes Signup and view all the answers

Which of the following correctly identifies a limitation of the ring topology?

Difficult to recover from failure of one node Signup and view all the answers

What type of connection is used in the bus topology?

RJ-45 cable or coaxial cable Signup and view all the answers

What is a notable feature of the data communication protocol mentioned in relation to duplex modes?

Maintains data integrity and order Signup and view all the answers

Which organization is NOT involved in defining the Physical layer technologies?

World Trade Organization (WTO) Signup and view all the answers

What is the primary purpose of encoding in the Physical layer?

To convert a stream of data bits into a predefined code Signup and view all the answers

Which of the following describes signaling in the Physical layer?

Generating electrical, optical, or wireless signals to represent bits Signup and view all the answers

Which of the following is a fundamental function of the Physical layer?

Encoding data into recognizable patterns Signup and view all the answers

What is NOT a characteristic that distinguishes network cables?

Color of the cable Signup and view all the answers

Which group establishes standards for signal representation on the Physical layer?

International Telecommunication Union (ITU) Signup and view all the answers

Which of the following statements about the Physical layer is false?

It is primarily concerned with routing data across networks. Signup and view all the answers

What role do national telecommunications authorities, such as the FCC, play regarding the Physical layer?

They define standards related to signal characteristics. Signup and view all the answers

What is a key characteristic of twisted-pair cables?

They consist of pairs of wires twisted together to reduce electromagnetic interference. Signup and view all the answers

Which type of cable is most suitable for high-frequency signals with minimal attenuation?

Fiber-optic cable Signup and view all the answers

What differentiates microwaves from radio waves in terms of communication?

Microwaves require directional antennas for point-to-point communication. Signup and view all the answers

What is a common disadvantage of wireless channels compared to guided media channels?

Higher susceptibility to errors and interference. Signup and view all the answers

Which statement about infrared communication is true?

It is suitable for communication in closed areas with line-of-sight propagation. Signup and view all the answers

What is a characteristic limitation of coaxial cables?

They are less capable of supporting high bandwidth than fiber-optic cables. Signup and view all the answers

Which type of antenna is commonly used for radio communications?

Omnidirectional antenna Signup and view all the answers

What defines the performance of optical fiber in fiber-optic cables?

The propagation modes of the light transmitted. Signup and view all the answers

What occurs at each node when a packet is transmitted through the network?

The packet is received, stored briefly, and then transmitted. Signup and view all the answers

Why is resource sharing important in packet-switching networks?

To save or make money by efficiently using network resources. Signup and view all the answers

What is the primary function of protocols in network communications?

To define the formats, timing, and actions of messages exchanged. Signup and view all the answers

Which organization is known as a non-treaty agency of the United Nations that develops IT standards?

ISO Signup and view all the answers

In the context of circuit switching, what is the primary characteristic of capacity allocation?

Fixed allocation regardless of actual usage. Signup and view all the answers

What scenario reflects advantageous use of packet switching?

When users have bursty communication patterns. Signup and view all the answers

What outcome is associated with contention in packet-switching networks?

Packets arrive simultaneously at the same destination. Signup and view all the answers

Which standard body is responsible for coordinating standards development across the United States?

ANSI Signup and view all the answers

What is a key characteristic of half duplex transmission?

Messages can only be sent one at a time. Signup and view all the answers

Which of the following is an example of full duplex transmission?

Local telephone calls Signup and view all the answers

What does the PTT switch do in half duplex systems?

Turns off the transmitter while receiving Signup and view all the answers

In which scenario is full/full duplex possible?

On multipoint circuits with multiple users Signup and view all the answers

What defines a two-wire circuit?

One wire transmits and the other acts as a return path. Signup and view all the answers

What is a feature of full duplex transmission that differentiates it from half duplex?

Simultaneous data transmission is allowed. Signup and view all the answers

Which type of circuit is characterized by the use of four insulated conductors?

Four-wires circuit Signup and view all the answers

What best describes simplex communication?

One-way only communication. Signup and view all the answers

What is the main characteristic of a bus topology?

All devices connect to a single main cable. Signup and view all the answers

What is a disadvantage of bus topology?

The cable length is limited, restricting connections. Signup and view all the answers

Which of the following accurately describes ring topology?

Each node has access to a token for communication. Signup and view all the answers

What is an advantage of ring topology?

It ensures a very orderly network for data transmission. Signup and view all the answers

What issue arises if one node fails in a ring topology?

The entire network could become non-functional. Signup and view all the answers

What is the purpose of the central hub in a star topology?

To manage and route data between nodes. Signup and view all the answers

What is a common disadvantage of ring topology compared to bus topology?

It is more prone to disruptions from single node failures. Signup and view all the answers

Which network topology is considered best suited for small networks due to its low cost and ease of installation?

Bus Topology Signup and view all the answers

Study Notes

Data Communications

Data communications is the exchange of data between two or more connected devices.

Introduction to Data Communications

Data can include text, images, audio, video, and multimedia files.
Communication is the act of sending or receiving data.
Data communication refers to the exchange of data between two or more networked devices.
These devices must be able to send and receive data via a communication medium.

Examples of Devices

Personal computers
Mobile phones
Laptops

Simple Network

A simple network comprises four types of devices: computer, printer, server, and switch.
These devices are interconnected through a medium to carry information from one end to the other.

Forces Driving Communication

The continual growth in data traffic
Development of new services
Advancements in technology

Intended Learning Outcomes

Define terms related to data, data communications, and data communication networks.
Describe the evolution of data communications.
Define data communications networks architecture.
Describe data communications protocols.
Explain the basic concepts of connection-oriented and connectionless protocols.
Describe syntax and semantics and how they relate to data communications.
Define data communication standards and explain their necessity.

Data vs Information

Data: Raw, unorganized facts and figures
Information: Data that is organized, structured, and processed to be meaningful.

Data Communications Model

Source: Generates data to be transmitted.
Transmitter: Converts data into transmittable signals.
Transmission system: Carries data from the source to the destination.
Receiver: Converts the received signal into data.
Destination: Takes incoming data.

Data Communications Do

Enables information systems to deliver information.
Improves the flexibility of data collections and transmission.
Forms the basis for virtual organizations.
Provides e-collaboration.

Basic Concepts of Data Communication

Bandwidth: Amount of data transferrable in a specific time period.
Attenuation: Loss of power in a signal as it travels.
Broadband: Simultaneous transmission of multiple data pieces to increase rate.
Narrowband: Limited transmission rate (e.g., voice-grade).
Protocols: Rules that govern data communication, including error detection, message length, and transmission speed.

5 Components of Data Communication

Sender
Protocol
Message
Medium
Receiver

Data Representation

Text: ASCII (7-bit) and Extended ASCII (8-bit), Unicode (32-bit).
Numbers: Binary numbers.
Images: Matrix of pixels.
Audio: Continuous analog signal.
Video: Can be analog or digital.

Data Flow

Simplex: One-way communication.
Half-duplex: Two-way communication, but not simultaneous.
Full-duplex: Two-way communication, simultaneous.

Networks

Growth of computers and their power created the need for interconnection.
Data, voice, and video technologies are rapidly integrating.
Two broad categories of networks: LANs and WANs

Network Components

Network: A collection of interconnected devices.
Node: A device capable of sending and receiving data.
Link: The path between nodes over which data travels.

Communication Media

Selection depends on internal or long-distance use.
Technology changes the mix of media (e.g., fiber optic, wireless).
Transmission costs are still high, necessitating efficiency improvements.
Types of media include: twisted pair wire, coaxial cable, fiber optic cable, radio, infrared, satellites.

Physical Structure

Type of connection: point-to-point (single transmitter/receiver); multipoint (multiple recipients of a single transmission).
Physical topology: Connection of devices (e.g., bus, star, ring, mesh, tree, hybrid)
Transmission type: unicast, multicast, broadcast.

Types of Connection

Point-to-Point Protocol (PPP): Defines the communication between two devices.
Multipoint Connection: A connection in which multiple devices share a single communications link.

Types of Network Topologies

Star Topology
Ring Topology
Bus Topology
Tree Topology
Hybrid Topology
Mesh Topology

Circuit Switching

A dedicated communication path is established for the duration of the conversation.
The path comprises a sequence of physical links, creating a dedicated logical channel.
Resources are dedicated throughout the call duration.
Example: Telephone network.

Packet Switching

Data is divided into small chunks called 'packets'.
Packets are sent along different paths, potentially out of sequence.
The network shares resources between packets.

Packet switching is more efficient compared to circuit switching when users are 'bursty', meaning they send and receive data in bursts interspersed with periods of inactivity.

Protocols

Rules that govern data communication between network elements.
Defines message formats, timing, and actions.

Standard Bodies

Organizations that define and standardize data communications.
Examples include: ISO, ITU, ANSI, IEEE, Telcordia, ETSI, IAB, IETF, IRTF, OMG, WWW consortium.

The Internet

Evolved from ARPANET.
First operational packet network.

Networking Today

Growth and interconnection of computers.

The Changing Environment

Devices accessing data & content via various networks (BYOD).

Network Trends; Online Collaboration; Cloud Computing

Cloud computing benefits (organizational flexibility, agility, reduced cost).

OSI Layer - Physical Layer

Controls how data is placed on physical media (copper wires, fiber optics, wireless).
Encodes binary digits into signals.
Transmits and receives signals across the media.

OSI Layer - Data Link Layer

Provides error-free communication across physical links.
Frames data into blocks to be transmitted.
Handles physical addressing and error detection.

OSI Layer - Network Layer

Enables routing data between different networks/subnetworks.
Includes routers and their software for data routing.

OSI Layer - Transport Layer

Controls the end-to-end integrity of data transmission.
Handles message routing, segmentation, error recovery.
Provides connection-oriented and connectionless services to upper-layer protocols.
The transport layer is the highest layer in the OSI hierarchy in terms of communications, and may provide data tracking, connection flow control, sequencing of data, error checking, and application addressing and identification.

OSI Layer - Session Layer

Responsible for network availability (data storage and processor capacity).
Provides logical connection entities for applications.
Includes network log-on/log-off and user authentication procedures.

OSI Layer - Presentation Layer

Ensures data independence for application processes.
Addresses code and syntax conversion for data presentation in a standard communication format.
Supports encryption, compression, and virtual terminals.

OSI Layer - Application Layer

Highest layer in the hierarchy, akin to the general manager of the network.
Provides access to the OSI environment.
Distributes information services, controlling interactions between applications and users.

Transmission Modes (Two-wire and Four-wire Circuits)

Two-wire circuits:
- Used for short distances.
- Generally analog.
- Lower quality/performance due to analog transmission.
Four-wire circuits:
- Facilitate multiple simultaneous communications in full duplex mode.
- Improve error performance due to digital transmission.

Transmission Media

Guided Media:
- Twisted-pair cable
- Coaxial cable
- Fiber-optic cable
Unguided Media:
- Radio waves
- Microwaves
- Infrared

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Description

Test your knowledge on various network topologies including bus, star, and ring. Understand the advantages and disadvantages of each topology, as well as their impact on data transmission. This quiz covers essential concepts in networking for students and professionals alike.