Introduction To Data Communications Flashcards
Q: What are the five components of data communication?
A:
Message: The information to be communicated (text, numbers, images, audio, video). Sender: The device that sends the message (e.g., computer, phone). Receiver: The device that receives the message (e.g., computer, TV). Transmission Medium: The physical path for data transmission (e.g., cables, radio waves). Protocol: Rules that govern data exchange (e.g., HTTP, TCP/IP).
Q: What are the four characteristics of an effective data communication system?
A:
Delivery: Data must reach the intended recipient only. Accuracy: Data must arrive without alteration. Timeliness: Data must be delivered on time (real-time for audio/video). Jitter: Minimal variation in packet arrival time.
Q: What are the modes of data flow in communication systems?
A:
Simplex: One-way communication (e.g., keyboard to monitor). Half-Duplex: Two-way communication, but only one direction at a time (e.g., walkie-talkies). Full-Duplex: Two-way simultaneous communication (e.g., phone calls).
Q: What are the key criteria for a network?
A:
Performance: Measured by throughput and delay. Reliability: Frequency of failures and recovery time. Security: Protection from unauthorized access and data loss.
Q: Describe the main network topologies.
A:
Mesh: Every device is connected to every other device.
Advantages: High robustness and privacy.
Disadvantages: High cost and cabling complexity.
Star: Devices connect to a central hub.
Advantages: Easy to install and robust.
Disadvantage: Hub failure affects the entire network.
Bus: All devices share a single backbone.
Advantages: Simple and cost-effective.
Disadvantages: Faults in the bus affect the entire network.
Ring: Devices form a closed loop, passing data in one direction.
Advantages: Easy to install and reconfigure.
Disadvantage: Single point of failure.
Q: What are the categories of networks and their key features?
A:
LAN (Local Area Network): Small area, high speed (e.g., office networks). WAN (Wide Area Network): Covers large distances using technologies like packet switching. MAN (Metropolitan Area Network): Connects LANs within a city using high-speed backbones.
Q: What are examples of commonly used Internet protocols?
A:
HTTP: For web data transfer. TCP/IP: For reliable communication between devices. SMTP: For email exchange.
Q: What are the two types of standards in networking?
A:
De Facto: Widely used but not officially approved (e.g., TCP/IP). De Jure: Approved by a recognized body (e.g., IEEE standards).
Q: What are examples of transmission mediums in data communication?
A:
Twisted-pair wire Coaxial cable Fiber-optic cable Radio waves
Q: How is data represented in communication systems?
A:
Text: ASCII or Unicode encoding. Numbers: Binary representation. Images: Matrix of pixels. Audio: Waveform recordings. Video: Sequence of images (frames) in motion.
Q: What is jitter, and why is it significant in data communication?
A:
Definition: Variation in packet arrival time.
Impact: Affects real-time applications like video streaming and VoIP.
Examples:
If the 2nd packet arrives 10ms earlier than expected: Clumping.
If it arrives 10ms late: Dispersion.
Q: What factors influence network performance?
A:
Transit Time: Time for data to travel from sender to receiver. Response Time: Time between a request and its response. Throughput: Amount of data transmitted per unit time. Delay: Time lag caused by congestion or hardware inefficiencies.
Q: What are key measures of network reliability?
A:
Frequency of failures. Recovery time after failures. Robustness during disasters
Q: Differentiate between point-to-point and multipoint connections.
A:
Point-to-Point: Dedicated link between two devices (e.g., phone line). Multipoint: A single link shared by multiple devices, either spatially or temporally.
Q: What are the pros and cons of mesh, star, bus, and ring topologies?
A:
Mesh:
Pros: High robustness, fast communication.
Cons: Expensive, complex cabling.
Star:
Pros: Easy to install, robust.
Cons: Hub failure disrupts the network.
Bus:
Pros: Cost-effective, simple.
Cons: Cable failure stops all transmissions.
Ring:
Pros: Easy reconfiguration.
Cons: A single break affects the network unless bypass mechanisms exist.
Q: How are networks categorized based on size and scope?
A:
LAN (Local Area Network): Small-scale, private. MAN (Metropolitan Area Network): City-wide network. WAN (Wide Area Network): Large-scale, spans countries or continents.
Q: How is the Internet organized hierarchically?
A:
ISP Tiers:
Tier 1: Backbone providers (global reach).
Tier 2: Regional providers.
Tier 3: Local providers.
Interconnection: LANs, MANs, and WANs are linked using TCP/IP.
Q: What are the main layers of the Internet Protocol Stack?
A:
Application Layer Transport Layer Network Layer Data Link Layer Physical Layer
Q: What organizations define networking standards?
A:
ISO (International Organization for Standardization) IEEE (Institute of Electrical and Electronics Engineers) IETF (Internet Engineering Task Force) ITU (International Telecommunication Union)
Q: What are the key elements of a protocol?
A:
Syntax: Data format and structure. Semantics: Meaning of data fields. Timing: Synchronization and speed of communication.
Q: What are the different types of network connections?
A:
Switched Networks: Use intermediary nodes for data transfer. Point-to-Point: Directly connects two devices. Wireless Networks: Uses radio waves or infrared signals.
Q: Why is packet switching preferred over circuit switching?
A:
Efficient use of bandwidth. Can handle multiple connections simultaneously. More robust to individual link failures.
Q: What are the main components of the Internet?
A:
Routers: Direct traffic between networks. ISPs: Provide Internet access to users. End Devices: User devices like PCs, phones. Backbone Networks: High-speed links connecting major ISPs.
Q: How do LAN, WAN, MAN, and SAN differ?
A:
LAN (Local Area Network): Small-scale; used in offices or campuses. WAN (Wide Area Network): Covers vast areas; interconnects LANs. MAN (Metropolitan Area Network): City-level coverage; connects multiple LANs. SAN (Storage Area Network): High-speed network for storage devices.
Q: What is virtualization in networking?
A: It involves creating virtual versions of network components (e.g., virtual machines, virtual switches) to enhance flexibility, scalability, and cost efficiency in modern infrastructures like cloud environments.
Q: Why is bandwidth critical in modern networking?
A: Bandwidth determines data transfer capacity. Higher bandwidth ensures smooth video streaming, fast downloads, and better cloud application performance.
Q: Match protocols to their functions:
A:
HTTP/HTTPS: Web browsing and secure data exchange. FTP: File transfers. DNS: Resolves domain names to IP addresses. SMTP: Sends emails. SSL/TLS: Encrypts data for secure transmission.
Q: Where are different topologies used?
A:
Mesh: Data centers needing reliability. Star: Corporate networks with a central hub. Ring: Legacy systems, some metropolitan networks. Bus: Rare today, found in simple LANs. Hybrid: Combines topologies for custom solutions.
Q: What are common network problems and solutions?
A:
Connectivity Loss: Check cables, ports, or wireless settings. Slow Performance: Monitor bandwidth usage and optimize routing. Security Breaches: Update firewalls and scan for malware.
Q: How have networking technologies evolved?
A: From ARPANET to modern TCP/IP-based networks, advancements include faster data rates, increased reliability, and secure communications.
Q: What are the OSI model layers and their purposes?
A:
Physical: Hardware connections. Data Link: Frames and error correction. Network: Routing and addressing. Transport: Ensures data reliability. Session: Manages communication sessions. Presentation: Data formatting. Application: Interfaces for network services.
Q: What are the types of cloud networks?
A:
Public Cloud: Services for multiple users, e.g., AWS. Private Cloud: Dedicated resources for a single organization. Hybrid Cloud: Combines public and private. Community Cloud: Shared infrastructure for specific groups.
Q: What are the key characteristics of effective data communication?
A: Delivery, accuracy, timeliness, and minimal jitter.
How does congestion impact delay?
Increases delay by queuing data packets at network nodes.
