Data Communication and Network Security Overview

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Questions and Answers

What are the three key characteristics that determine the effectiveness of a network?

Speed, Security, Reliability

Delivery, Accuracy, Timeliness (correct)

Cost, Accessibility, Complexity

Scalability, Modularity, Flexibility

Which of the following is NOT one of the components involved in a network process?

Receiver

Message

Router (correct)

Sender

Which factor does NOT affect the performance of a network?

Number of users

Type of transmission medium

Data recovery methods

Frequency of data encryption (correct)

What is a primary role of the transmission medium in a network?

To serve as the physical path for data to travel Signup and view all the answers

Which characteristic is concerned with the system's ability to deliver data accurately?

Accuracy Signup and view all the answers

What is primarily the focus of network security?

Protecting data from unauthorized access and viruses Signup and view all the answers

Which of the following is considered a network type?

Packet-switched network Signup and view all the answers

What component is described as the device that sends the data messages?

Sender Signup and view all the answers

What is a common disadvantage of ring topology?

Failure of one computer disrupts the entire network. Signup and view all the answers

Which of the following describes a characteristic of tree topology?

It requires at least three levels to establish its hierarchy. Signup and view all the answers

What is a disadvantage of star topology?

If the hub fails, the entire network goes down. Signup and view all the answers

What makes tree topology advantageous for organization?

Management and maintenance are simplified. Signup and view all the answers

In which scenario is ring topology likely to perform best?

In small networks with limited devices. Signup and view all the answers

Which topology allows easy addition of nodes?

Star topology. Signup and view all the answers

Why is troubleshooting in ring topology difficult?

Disruptions can affect nodes that do not even have issues. Signup and view all the answers

What limitation is associated with the length of cables in a network?

There is a limited length for effective cable connections. Signup and view all the answers

What is a primary disadvantage of mesh topology?

It is difficult to install and configure. Signup and view all the answers

Which of the following best describes hybrid topology?

A combination of two or more different basic topologies. Signup and view all the answers

What aspect of mesh topology allows it to be robust?

Connection can carry independent data load. Signup and view all the answers

What is a major advantage of using a Local Area Network (LAN)?

Data is transferred at extremely faster rates. Signup and view all the answers

What is a disadvantage associated with hybrid topology?

It is overly complex in design. Signup and view all the answers

How are physical links calculated in a fully connected mesh network with n nodes?

$n (n - 1) / 2$ Signup and view all the answers

Which type of network covers a city and connects multiple LANs?

Metropolitan Area Network (MAN) Signup and view all the answers

What is one key feature of Local Area Networks (LANs) regarding cost?

They are generally less costly than other network types. Signup and view all the answers

What is a primary disadvantage of a Local Area Network (LAN)?

Data Security Threat Signup and view all the answers

Which statement accurately describes a Wide Area Network (WAN)?

It spans large geographic areas such as states or countries. Signup and view all the answers

What is a notable characteristic of a Metropolitan Area Network (MAN)?

It interconnects various LANs over a small area. Signup and view all the answers

What common issue is associated with Wide Area Networks (WANs)?

Increased security risks Signup and view all the answers

Which of the following is a common advantage of using LANs?

Resource Sharing Signup and view all the answers

What defines an internetwork?

It is a collection of multiple networks like LANs and WANs. Signup and view all the answers

Which of the following statements is a disadvantage of using a WAN?

Requires extensive troubleshooting. Signup and view all the answers

What is an extranet primarily used for?

For information sharing between organizations. Signup and view all the answers

What is the primary function of the middle core in a coaxial cable?

To transmit data Signup and view all the answers

Which type of transmission allows multiple signals to be sent simultaneously over coaxial cable?

Broadband transmission Signup and view all the answers

What material is typically used for the inner conductor of a coaxial cable?

Copper Signup and view all the answers

Which of the following is NOT an advantage of coaxial cables compared to twisted pair cables?

Greater cost-effectiveness Signup and view all the answers

In a fiber optic cable, what is the role of the plastic coating?

To protect fibers from heat and electromagnetic interference Signup and view all the answers

What does the RG rating of coaxial cables signify?

A unique set of physical specifications Signup and view all the answers

Which type of fiber optic cable offers higher speed data transmission?

Single-mode fiber Signup and view all the answers

What is a major disadvantage of coaxial cables in network applications?

Entire network failure from a single fault Signup and view all the answers

What is the primary responsibility of the connection-oriented approach in the transport layer?

Make a connection before delivering data. Signup and view all the answers

Which function does the session layer perform to manage data transmission errors?

Creating checkpoints for synchronization and recovery. Signup and view all the answers

What role does the presentation layer play in data communication?

Translating between different encoding formats. Signup and view all the answers

How does the transport layer handle flow control?

Through end-to-end control methods. Signup and view all the answers

Which type of dialog control is managed by the session layer?

Managing both half-duplex and full-duplex communication. Signup and view all the answers

What function of the presentation layer is used to enhance data transmission by reducing its size?

Compression and expansion. Signup and view all the answers

What process allows the application layer to facilitate user access to the network?

Resource allocation. Signup and view all the answers

What is meant by synchronization in the context of the session layer?

Creating checkpoints for retransmission in case of errors. Signup and view all the answers

Study Notes

Network Effectiveness

Three key characteristics determine the effectiveness of a network:
- Performance: Measured by speed and efficiency of data transfer.
- Reliability: Capacity to transmit data without errors.
- Security: Protecting the network from unauthorized access.
Components involved in a network process:
- Data: Information transmitted across the network.
- Sender: Device that originates the data transmission.
- Receiver: Device that receives the data.
- Transmission medium: The physical path (cable, wireless) through which data travels.
- Network protocols: Rules that govern how data is exchanged.
- Network software: Software that manages network resources and communication.
Factors that do not affect network performance:
- Number of users connected: This can affect performance, not the non-impactful factor.
- Type of network topology: This affects the network's structure, but not its performance.
- Network security measures: Impact security, but not the performance.
Transmission Medium:
- Its primary role is to carry data signals between network devices.
Reliability in Network:
- The characteristic of reliable network is its ability to deliver data accurately.
Network Security:
- Focuses on protecting the network from unauthorized access, data breaches, and other threats.
Network Types:
- LAN (Local Area Network): Connects devices in a small area, like a home or office.
- WAN (Wide Area Network): Connects networks over a large geographical area, e.g., across cities or countries.
- MAN (Metropolitan Area Network): Covers a city and connects multiple LANs.
- Extranet: A private network extended beyond the organization, allowing outside access to specific resources.
Sender:
- In a network, it is the device sending the data messages.
- Also known as "source device" or "transmitter."

Network Topologies

Ring Topology:
- Disadvantage: Failure of one node can disrupt the entire network.
Tree Topology:
- Characteristics:
  - Hierarchical structure, like an upside-down tree.
  - Each node has a parent and can have multiple children.
- Advantage:
  - Easy to manage and expand due to its hierarchical structure.
Star Topology:
- Disadvantage:
  - Central hub is a single point of failure, entire network goes down if the hub fails.
- Advantage:
  - Easy to troubleshoot and isolate problems as each node connects directly to the hub.
Tree Topology:
- Advantage:
  - Suitable for large networks and hierarchical organizations where there's a clear chain of command.
Ring Topology:
- Best Performance:
  - Most efficient in handling traffic in a closed loop where data flows continuously.
Bus Topology:
- Advantage:
  - Easy to add new nodes due to its linear structure.
Ring Topology:
- Troubleshooting Difficulties:
  - Hard to isolate problems as data flows continuously in a loop, making it difficult to identify the faulty node.
Cable Length:
- Limitation:
  - Longer cables can lead to signal degradation and slower speeds, there are limitations on the maximum length of a single cable.
Mesh Topology:
- Primary Disadvantage:
  - Complex installation and wiring, many cables are required to connect every node to each other.
Hybrid Topology:
- Description:
  - Combines two or more different topologies to create a more efficient and robust network.
Mesh Topology:
- Robustness:
  - Highly reliable as there are multiple paths for data to travel, if one path fails others can be used.
Local Area Network (LAN):
- Advantage:
  - Lower cost than larger WANs, as the coverage area is smaller.
Hybrid Topology:
- Disadvantage:
  - Potentially complex to manage due to the combination of different topologies.
Mesh Topology:
- Number of Physical Links:
  - Calculated as n(n-1)/2, where 'n' is the number of nodes.
Metropolitan Area Network (MAN):
- Covers a city and connects multiple LANs, e.g., connecting businesses, universities, and government agencies within a city.
Local Area Network (LAN):
- Cost:
  - Lower initial investment than other types because of its smaller coverage area.
Local Area Network (LAN):
- Disadvantage:
  - Limited geographical coverage, restricted to a small area, such as a single building or campus.
Wide Area Network (WAN):
- Description:
  - Connects networks over a large geographical area using public communication channels like leased lines, satellite links, or internet services.
Metropolitan Area Network (MAN):
- Characteristic:
  - High bandwidth capacity to handle larger volumes of data traffic compared to LANs.
Wide Area Network (WAN):
- Issue:
  - Higher latency as data travels over long distances, causing delays in data communication.
Local Area Network (LAN):
- Advantages:
  - Higher bandwidth, faster data transfer speeds within the network because of shorter distances.
  - Centralized resources, like printers and servers, can be shared by all users on the network.
Internetwork:
- Defined as interconnected networks that use common protocols to allow seamless data transfer and communication.
Wide Area Network (WAN):
- Disadvantage:
  - High setup costs due to the need for leased lines, infrastructure, and specialized equipment for long-distance communication.
Extranet:
- Primary Use:
  - Securely extend network functionality to external partners, suppliers, or customers, allowing them access to specific resources.
Coaxial Cable:
- Middle Core:
  - Primarily acts as a shield to prevent interference from external signals.
Coaxial Cable:
- Multiplexing:
  - Frequency Division Multiplexing (FDM) is used to transmit multiple signals simultaneously by dividing the available bandwidth into frequency bands. Each signal occupies a separate frequency band, allowing multiple messages to share the same cable.
Coaxial Cable:
- Inner Conductor:
  - Usually made of copper.
Coaxial Cable:
- Advantages:
  - Durable, less susceptible to interference than twisted pair.
  - Suitable for high-frequency signals.
  - Higher bandwidth than twisted pair.
  - Lesser attenuation than twisted pair, meaning signal strength loss over long distances is less.
- Not an advantage:
  - Costly, compared to twisted pair cables.
Fiber Optic Cable:
- Plastic Coating:
  - Provides protection to the optical fiber core and cladding.
Coaxial Cable:
- RG rating:
  - Indicates the cable's impedance and size.
Fiber Optic Cable:
- Higher Speed:
  - Single-mode fiber optic cables support higher data transmission speeds than multimode cables.

Network Communication Layers

Coaxial Cables:
- Disadvantage in Networking:
  - Difficult to use in complex networks where multiple signals need to be sent simultaneously. The bandwidth limitations and susceptibility to interference become apparent in these environments.
Transport Layer:
- Connection-Oriented Approach:
  - Ensures reliable delivery of data by establishing a connection before sending any data.
  - Provides flow control to prevent overwhelming the receiver and ensures error checking using acknowledgements.
Session Layer:
- Function:
  - Manages the dialog between applications on different computers.
  - Provides data transfer synchronization and recovery from errors.
Presentation Layer:
- Role:
  - Responsible for data formatting and presentation to ensure compatibility between different applications.
Transport Layer:
- Flow Control:
  - Ensures data is transmitted at a pace that the receiver can handle, preventing data loss or congestion.
Session Layer:
- Dialog Control:
  - Manages half-duplex or full-duplex communication.
  - Half-duplex allows data to flow in one direction at a time, like a walkie-talkie.
  - Full-duplex communication allows simultaneous data flow in both directions, like a phone conversation.
Presentation Layer:
- Function for Data Transmission Enhancement:
  - Data compression to reduce data size before transmission.
Application Layer:
- User Access to Network:
  - Provides user-friendly interfaces for applications to interact with the network.
  - Examples: Browsers, email clients, file transfer protocols.
Session Layer:
- Synchronization:
  - Ensures that data is transmitted and received in the correct order.
  - Uses ** checkpoints** to mark significant points in data transfer, allowing the session to resume seamlessly after disruptions, ensuring data integrity and reliability.

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Description

This quiz covers foundational concepts in data communication and network security, including protocols, standards, and the OSI model. Explore various network types, topologies, and transmission media, and understand the factors influencing transmission design. Test your knowledge on essential networking principles and their applications.