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Questions and Answers
Which data communication characteristic ensures data reaches the intended recipient?
Which data communication characteristic ensures data reaches the intended recipient?
What constitutes a 'message' in a data communication system?
What constitutes a 'message' in a data communication system?
What is the primary function of a protocol in data communication?
What is the primary function of a protocol in data communication?
Which data representation method uses 32 bits to represent symbols and characters?
Which data representation method uses 32 bits to represent symbols and characters?
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In image representation, what does a matrix of pixels define?
In image representation, what does a matrix of pixels define?
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In simplex mode, which communication pattern is used?
In simplex mode, which communication pattern is used?
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What is a 'jitter' in data communication?
What is a 'jitter' in data communication?
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In half-duplex communication, what is the transmission characteristic?
In half-duplex communication, what is the transmission characteristic?
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What is the primary function of an interface in protocol hierarchies?
What is the primary function of an interface in protocol hierarchies?
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Which of the following is a key design issue that must be addressed in network layers?
Which of the following is a key design issue that must be addressed in network layers?
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Why is error control necessary in network communication?
Why is error control necessary in network communication?
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What problem does flow control aim to solve in network communication?
What problem does flow control aim to solve in network communication?
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What is the purpose of multiplexing in network communication?
What is the purpose of multiplexing in network communication?
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When is routing necessary in network communication?
When is routing necessary in network communication?
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How does a connection-oriented service differ from a connectionless service?
How does a connection-oriented service differ from a connectionless service?
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What is the primary purpose of the OSI model?
What is the primary purpose of the OSI model?
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Which function is NOT a primary responsibility of the session layer?
Which function is NOT a primary responsibility of the session layer?
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What is the purpose of adding checkpoints in the session layer?
What is the purpose of adding checkpoints in the session layer?
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In which communication mode, does the session layer allows two systems to start communication with each other?
In which communication mode, does the session layer allows two systems to start communication with each other?
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How is the session layer represented in the TCP/IP model?
How is the session layer represented in the TCP/IP model?
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Why is it advisable to insert checkpoints when transmitting a large file?
Why is it advisable to insert checkpoints when transmitting a large file?
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What is the primary function of the transport layer?
What is the primary function of the transport layer?
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What is the name given to data in the transport layer?
What is the name given to data in the transport layer?
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What is the significance of the destination port number in the transport layer header?
What is the significance of the destination port number in the transport layer header?
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Which layer defines the transmission rate (bits per second) in data communication?
Which layer defines the transmission rate (bits per second) in data communication?
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Which of the following is an example of a Physical Layer device?
Which of the following is an example of a Physical Layer device?
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What mechanism does the Data Link Layer (DLL) primarily use to transmit a packet to a host?
What mechanism does the Data Link Layer (DLL) primarily use to transmit a packet to a host?
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In the TCP/IP protocol suite, what type of address is used at the Network Layer?
In the TCP/IP protocol suite, what type of address is used at the Network Layer?
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What is the purpose of the ARP (Address Resolution Protocol) request in the context of the Data Link Layer?
What is the purpose of the ARP (Address Resolution Protocol) request in the context of the Data Link Layer?
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Which of the following statements best explains why the OSI model did not fully replace the TCP/IP protocol suite?
Which of the following statements best explains why the OSI model did not fully replace the TCP/IP protocol suite?
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Which of the following layers is NOT present in the TCP/IP protocol suite, but is present in the OSI model?
Which of the following layers is NOT present in the TCP/IP protocol suite, but is present in the OSI model?
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Which of the following is the MOST direct responsibility of the Data Link Layer?
Which of the following is the MOST direct responsibility of the Data Link Layer?
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What happens if the data rate is not constant between sender and receiver, according to the content?
What happens if the data rate is not constant between sender and receiver, according to the content?
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Which sub-layer determines which device takes control over the channel?
Which sub-layer determines which device takes control over the channel?
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Which of the following is primarily responsible for error detection and retransmission of damaged frames?
Which of the following is primarily responsible for error detection and retransmission of damaged frames?
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What is the fundamental unit of data in the Physical Layer?
What is the fundamental unit of data in the Physical Layer?
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What function does the clock provide in the Physical Layer?
What function does the clock provide in the Physical Layer?
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Which of the following describes the 'syntax' element of a protocol?
Which of the following describes the 'syntax' element of a protocol?
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Which organization does not contribute significantly to setting standards in today's international communications?
Which organization does not contribute significantly to setting standards in today's international communications?
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Which of the following best describes the concept of 'protocol layering' in network design?
Which of the following best describes the concept of 'protocol layering' in network design?
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In a layered network model, how is data typically transferred between layer 'n' of one machine to layer 'n' of another machine?
In a layered network model, how is data typically transferred between layer 'n' of one machine to layer 'n' of another machine?
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Which of the following statements accurately distinguishes between 'hardware' and 'software' in a network context?
Which of the following statements accurately distinguishes between 'hardware' and 'software' in a network context?
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What is the primary goal of standards organizations like ISO, ITU-T, and ANSI in the context of computer networks?
What is the primary goal of standards organizations like ISO, ITU-T, and ANSI in the context of computer networks?
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What aspect of data transmission is most directly addressed by the 'timing' element of a network protocol?
What aspect of data transmission is most directly addressed by the 'timing' element of a network protocol?
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What would happen if two entities on a network did not agree on a common communication protocol?
What would happen if two entities on a network did not agree on a common communication protocol?
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Flashcards
Data Communication
Data Communication
The exchange of data between two devices through a medium.
Delivery
Delivery
Ensures data reaches the correct destination.
Jitter
Jitter
Variation in packet arrival time affecting quality.
Transmission Medium
Transmission Medium
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Protocol
Protocol
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Bit Pattern
Bit Pattern
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Simplex
Simplex
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Half-Duplex
Half-Duplex
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Syntax
Syntax
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Semantics
Semantics
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Timing
Timing
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Standards
Standards
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Protocol Layering
Protocol Layering
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Hardware in Networks
Hardware in Networks
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Software in Networks
Software in Networks
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Session Layer Functions
Session Layer Functions
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Synchronization in Session Layer
Synchronization in Session Layer
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Dialog Controller
Dialog Controller
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Purpose of Checkpoints
Purpose of Checkpoints
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Transport Layer Function
Transport Layer Function
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Data Units in Transport Layer
Data Units in Transport Layer
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Segmentation and Reassembly
Segmentation and Reassembly
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Port Numbers
Port Numbers
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Data Link Layer (DLL)
Data Link Layer (DLL)
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Frame
Frame
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MAC Address
MAC Address
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ARP (Address Resolution Protocol)
ARP (Address Resolution Protocol)
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Framing
Framing
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Error Control
Error Control
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Flow Control
Flow Control
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Physical Layer
Physical Layer
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Protocol Hierarchies
Protocol Hierarchies
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Addressing
Addressing
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Multiplexing
Multiplexing
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Routing
Routing
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Connection Oriented
Connection Oriented
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Open Systems Interconnection (OSI) Model
Open Systems Interconnection (OSI) Model
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Bit Rate Control
Bit Rate Control
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Transmission Modes
Transmission Modes
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TCP/IP Protocol Suite
TCP/IP Protocol Suite
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Network Layer Address
Network Layer Address
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OSI Model vs TCP/IP
OSI Model vs TCP/IP
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Study Notes
Data Communications
- Data communication is the exchange of data between two devices through a medium, like a wire cable.
- Four fundamental characteristics that data communication depends on include:
- Delivery: Data must be delivered to the correct destination.
- Accuracy: Data must be delivered accurately.
- Timeliness: Time is a factor in the delivery of data.
- Jitter: Variation in packet arrival time can affect the quality of data, especially video.
Data Communication Systems Components
- Message: Information in any form (text, numbers, images, audio, video).
- Sender: Device initiating the data message (computer, workstation, camera).
- Receiver: Device receiving the data message (computer, television).
- Transmission medium: Physical path for data transmission (wire cable, coaxial cable, fiber optic cable).
- Protocol: Set of rules governing data communication between devices. Without protocols, two devices may be connected but not communicate.
Data Representation
- Text: Represented by bit patterns (sequences of 0s and 1s). Different coding systems exist, like Unicode (using 32 bits per symbol) and ASCII (American Standard Code for Information Interchange, with 127 characters).
- Numbers: Represented by bit patterns.
- Images: Composed of pixels (small dots). Pixel values represent the color (e.g., black = 00, white = 11).
- Audio: Recording or broadcasting of sound or music.
- Video: Recording or broadcasting of pictures or movies.
Data Flow
- Simplex: Unidirectional communication (one-way street). Only one device can transmit, the other only receives. (e.g., keywords and traditional monitors).
- Half-Duplex: Both devices can transmit and receive, but not simultaneously. (e.g., walkie-talkies, crossing road by a car).
- Full-Duplex: Both devices can transmit and receive simultaneously. (e.g., telephone network).
Network
- A network is an interconnection of devices for communication. (computers, desktops, laptops, cell phones).
- Criteria for networks include performance (measured by transit time and response time), reliability (measured by frequency of failure and recovery time), and security (protecting data from unauthorized access).
Physical Structures
- Types of connections: A network links two or more devices.
- Point-to-Point: Dedicated link between two devices; the entire link capacity is reserved for transmission. Examples include changing channels on a device from remote to TVs/satellite link.
- Multipoint: More than one device shares the same link.
LAN Topologies (Physical)
- LAN Topology: Geometric arrangement of LAN components.
- Mesh Topology: Every device has a dedicated point-to-point link to every other device. Dedicated point to point links carry traffic only between the two devices. The physical links for n nodes require n(n-1) links, or , n(n-1)/2 if both directions duplex mode is used.
- Advantages: Dedicated link guarantees data load; fault isolation/identification is easy; privacy/security possible.
- Disadvantages: The sheer bulk of wiring can exceed available space, increasing the number of I/O ports.
- Star Topology: A common point connects all devices; each device can access the media independently. Star topology is the dominant topology in modern LANs, rendering bus and ring topologies outdated.
- Advantages: Easier to manage, higher performance than bus topology, failure of one node or link does not affect the rest of the network.
- Disadvantages: If the central device fails, the entire network is down; costs increase with a switch or router as the central device.
- Bus Topology: All devices are connected to a single cable. Both ends of the cable must be terminated.
- Advantages: Easy to implement and extend (especially with temporary networks); typically less expensive.
- Disadvantages: Difficult to administer/troubleshoot; limited cable length and number of stations; a break in the cable disables the whole network; maintenance can be high in the long run; performance degrades with added computers.
- Ring Topology: Devices are connected in a closed loop. Data is transmitted unidirectionally around the ring.
- Advantages: Highly organized and efficient; eliminating the need for a network server; additional components do not affect network performance; each computer has equal access to resources. Advantages: Highly organized and efficient; eliminating the need for a network server; additional components do not affect network performance; each computer has equal access to resources.
- Disadvantages: If one workstation or port fails, the whole network suffers; the network depends entirely on the connecting cable.
Network Types
- LAN: Local Area Network. Covers a limited geographic area (less than 1km). Data flow capacity of 10 Mbps to 1 Gbps. Typical of a building or campus.
- MAN: Metropolitan Area Network. Covers a larger geographic area (1-10 km), linking local area networks, like a city.
- WAN: Wide Area Network. Network spans a large geographic area, including states, countries, or even the entire world.
Protocols and Standards
- Protocols: Set of rules and conventions for communication between entities in computer networks (computers, devices). An entity is capable of sending/receiving information.
- Key elements of a protocol: Syntax (structure/format of data); Semantics (meaning of bits); Timing (when data should be sent and how fast).
- Standards: Guidelines for manufacturers, vendors, and other service providers to ensure interconnectivity.
- Organizations that establish standards: ISO (International Organization for Standardization); ITU-T (International Telecommunication Union - Telecommunication Standards Sector); ANSI (American National Standards Institute); IEEE (Institute of Electrical and Electronics Engineers).
Network Models
- Protocol layering: An approach to structuring communication networks where layers operate in a hierarchical manner. Each layer builds upon the layer below it.
- Layered tasks: Each layer uses the services of the layers beneath to perform its assigned functions. This hierarchy makes design complexity more manageable.
OSI Model
- A standard reference model for communication between two end-users.
- Deals with connecting open systems (systems that can communicate with each other).
- Seven layers for communication: Application, Presentation, Session, Transport, Network, Data Link, and Physical.
TCP/IP Protocol Suite
- A practical layering model for the internet that emerged before the OSI model.
- Composed of five layers: Application, Transport, Network, Data Link, and Physical,
- Missing two layers compared to OSI.
Data Transfer (Connection Oriented/Connection Less)
- Connection-Oriented: Modeled after the telephone system; involves initial connection establishment, data transfer, and final disconnection. It is reliable and secure.
- Connectionless: Modeled after the postal system; each message has the complete destination information in the header and is routed independently of other messages. This type of method is faster but less secure.
Encapsulation/Decapsulation
- Encapsulation: Adding headers/trailers to data at each layer.
- Decapsulation: Removing headers/trailers at each layer in the receiving host. Routers take packets, remove headers/trailers from the top layer and add new headers/trailers.
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Description
Test your knowledge of key concepts in data communication with this quiz. Explore topics such as data representation, protocols, transmission modes, and error control. Perfect for students or anyone interested in the principles of network communication.
