Computer Networks important Questions Of BCA 5th Semester CCSU

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1. What do you understand by distributed processing?

Distributed processing refers to the use of multiple computers or processors connected via a network to share computational tasks. The goal is to divide large problems into smaller parts, which can be processed simultaneously to improve efficiency and performance.

Features:

• Resource Sharing: Resources such as files and printers can be shared across systems.
• Scalability: Systems can be scaled by adding more processors.
• Fault Tolerance: If one node fails, others can continue processing.
• Examples: Cloud computing, distributed databases, and blockchain.

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2. Differentiate between TDM and FDM.

Feature	TDM (Time Division Multiplexing)	FDM (Frequency Division Multiplexing)
Definition	Divides time into slots and assigns each user a time slot.	Divides the frequency spectrum into bands, assigning each user a separate band.
Data Transmission	Sequential (time-based).	Simultaneous (frequency-based).
Synchronization	Requires precise synchronization.	Does not require synchronization.
Efficiency	More efficient for digital signals.	More efficient for analog signals.
Example	Telephone networks (digital systems).	Radio and television broadcasting.

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3. What is the DTE-DCE interface?

DTE (Data Terminal Equipment) and DCE (Data Communication Equipment) refer to the devices and their interface in a communication system.

• DTE: Devices like computers or terminals that generate or receive data.
• DCE: Devices like modems or routers that establish, maintain, and terminate connections.

The DTE-DCE interface defines the physical and logical connection between these devices, enabling communication. Common standards include RS-232 and V.35.

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4. Write a short note on computer networks and e-mail.

• Computer Network:
  A computer network is a collection of interconnected devices (computers, servers, printers, etc.) that share resources and communicate.
  Types: LAN, WAN, MAN, PAN.
  Applications: File sharing, online communication, and resource sharing.

• E-mail:
  E-mail is a method of exchanging digital messages over the internet.
  Components:

  • SMTP (Simple Mail Transfer Protocol) for sending emails.
  • POP/IMAP for receiving emails.
    Advantages: Cost-effective, fast communication, and supports attachments.

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5. Explain attenuation in a signal.

Attenuation refers to the loss of signal strength as it travels through a medium, such as a cable or wireless channel.

• Causes: Distance, interference, and the medium's resistance.
• Effects: Reduced signal quality and increased error rates.
• Solutions:
  • Amplifiers to boost signal strength.
  • Repeaters to regenerate the signal.
  • Shorter transmission distances.

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6. Differentiate between Gateways and Routers.

Feature	Gateways	Routers
Definition	Connects two different networks using different protocols.	Connects multiple networks using the same protocol.
Layer	Works at all layers of the OSI model.	Works at the network layer of the OSI model.
Function	Protocol conversion and data translation.	Routing data packets between networks.
Example	Connecting LAN to WAN.	Connecting two LANs.

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7. What are the services of the transport layer?

The transport layer in the OSI model provides reliable data delivery between systems.

Services:

1. Segmentation and Reassembly: Divides data into smaller packets and reassembles them at the destination.
2. Error Detection and Correction: Ensures data integrity during transmission.
3. Flow Control: Manages data flow to prevent congestion.
4. Connection Establishment: Establishes, maintains, and terminates connections.
5. Multiplexing: Allows multiple applications to share the same connection.

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8. Differentiate Bridges and Repeaters.

Feature	Bridges	Repeaters
Definition	Connects two or more LAN segments.	Amplifies and regenerates signals.
Layer	Works at the data link layer.	Works at the physical layer.
Function	Filters and forwards data based on MAC addresses.	Regenerates weak signals to extend distance.
Usage	Reducing traffic within a network.	Extending the range of a network.

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9. Explain Ethernet protocol.

The Ethernet protocol is a widely used standard for local area networks (LANs).

• Standards: IEEE 802.3.
• Transmission Method: Uses a CSMA/CD (Carrier Sense Multiple Access with Collision Detection) technique to manage access to the network.
• Speed: Supports speeds from 10 Mbps to 100 Gbps.
• Advantages: High speed, reliability, and cost-effectiveness.

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10. (a) Explain topology and its types with advantages and disadvantages.

• Topology: The physical or logical arrangement of devices in a network.

Types:

1. Star Topology: All devices connect to a central hub.
   • Advantages: Easy to set up and troubleshoot.
   • Disadvantages: Single point of failure.
2. Bus Topology: Devices are connected to a single communication line.
   • Advantages: Cost-effective.
   • Disadvantages: Difficult to troubleshoot.
3. Ring Topology: Devices are connected in a circular manner.
   • Advantages: Data flows in one direction, reducing collisions.
   • Disadvantages: Failure in one node affects the entire network.
4. Mesh Topology: Every device is connected to every other device.
   • Advantages: High reliability.
   • Disadvantages: Expensive and complex.

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(b) Explain Transmission Mode.

Transmission modes define the direction of data flow between devices:

1. Simplex: One-way communication. Example: Keyboard to monitor.
2. Half-Duplex: Two-way communication, but only one direction at a time. Example: Walkie-talkie.
3. Full-Duplex: Simultaneous two-way communication. Example: Telephone.

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(c) Explain Data Communication.

Data communication is the exchange of data between devices through a transmission medium (wired or wireless).

Key Components:

• Sender: The device sending the data.
• Receiver: The device receiving the data.
• Medium: The channel through which data travels.
• Message: The data being communicated.
• Protocol: Rules governing the communication.

Characteristics: Delivery, accuracy, timeliness, and security.

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Here are accurate and detailed answers for the 5 marks questions:

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11. Brief about the importance of Simple Network Management Protocol (SNMP).

Simple Network Management Protocol (SNMP) is a protocol used for managing devices in a network. It enables network administrators to monitor, manage, and configure network devices (e.g., routers, switches, servers).

Importance:

1. Device Monitoring: Collects data about device performance, uptime, and error rates.
2. Fault Management: Alerts administrators about issues in real-time using trap messages.
3. Scalability: Supports large-scale networks with centralized management.
4. Flexibility: Works across diverse devices and vendors.
5. Automation: Simplifies tasks like updating firmware or adjusting configurations.

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12. Draw a neat diagram of OSI model and explain the functioning of each layer.

OSI Model Diagram:

+---------------------+
| Application Layer   |
+---------------------+
| Presentation Layer  |
+---------------------+
| Session Layer       |
+---------------------+
| Transport Layer     |
+---------------------+
| Network Layer       |
+---------------------+
| Data Link Layer     |
+---------------------+
| Physical Layer      |
+---------------------+

Functioning of Each Layer:

1. Physical Layer: Handles raw data transmission over physical media (cables, radio waves).
2. Data Link Layer: Ensures error-free data transfer between adjacent nodes using MAC addresses.
3. Network Layer: Handles logical addressing (IP) and routing of data packets.
4. Transport Layer: Provides reliable data transfer using protocols like TCP/UDP.
5. Session Layer: Manages and controls connections (sessions) between devices.
6. Presentation Layer: Ensures data is in a readable format, handling encryption and compression.
7. Application Layer: Interfaces with user applications (e.g., web browsers, email clients).

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13. Explain:

(a) Ring & Star Topology

• Ring Topology: Devices are connected in a circular structure.

  • Advantages: Data flows in one direction, reducing collisions.
  • Disadvantages: Failure in one device affects the entire network.

• Star Topology: Devices are connected to a central hub.

  • Advantages: Easy to troubleshoot and scalable.
  • Disadvantages: Central hub failure affects the whole network.

(b) LAN and MAN

• LAN (Local Area Network): Covers a small area like a building.
  • High speed, low cost, limited coverage.
• MAN (Metropolitan Area Network): Covers a city or town.
  • Moderate speed, higher cost, wider coverage.

(c) Transmission Modes

• Simplex: One-way communication (e.g., TV broadcast).
• Half-Duplex: Two-way communication, but one direction at a time (e.g., walkie-talkies).
• Full-Duplex: Simultaneous two-way communication (e.g., phone calls).

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14. Discuss Point-to-Point Protocol (PPP).

Point-to-Point Protocol (PPP) is a data link protocol used to establish a direct connection between two devices, often over serial links.

Features:

1. Framing: Defines a standard way to encapsulate network-layer data.
2. Authentication: Supports protocols like PAP and CHAP for secure connections.
3. Error Detection: Uses cyclic redundancy check (CRC).
4. Multiprotocol Support: Works with multiple protocols like IP, IPX, etc.

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15. Explain error detection and error correction code.

• Error Detection: Identifies errors in transmitted data using techniques like parity check, checksum, and cyclic redundancy check (CRC).

  • Example: CRC detects errors in data blocks during transmission.

• Error Correction: Fixes errors in the received data without retransmission.

  • Example: Hamming Code adds redundant bits to identify and correct single-bit errors.

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16. Write short notes on:

(a) Throughput & Wavelength:

• Throughput: Measures the actual data transferred per second in a network (e.g., Mbps).
• Wavelength: The distance between two peaks of a signal wave; affects transmission speed and bandwidth.

(b) Synchronous Protocols:

• Transfer data blocks at regular intervals using a clock signal (e.g., HDLC).
• Reliable but requires precise timing.

(c) Routers:

• Network devices that forward packets based on IP addresses.
• Operates at the network layer of the OSI model.

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17. Explain TCP packet format in detail.

TCP Packet Format:

Field	Description
Source Port	Identifies the sender's port.
Destination Port	Identifies the receiver's port.
Sequence Number	Ensures proper data ordering.
Acknowledgment Number	Confirms receipt of data.
Data Offset	Specifies the header length.
Flags	Control bits (e.g., SYN, ACK).
Window Size	Specifies available buffer space.
Checksum	Ensures data integrity.
Urgent Pointer	Points to urgent data (if any).
Data Payload	Contains the actual data being transmitted.

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18. Write short notes:

(a) ISDN (Integrated Services Digital Network):

• A digital communication system for voice, video, and data over telephone lines.

(b) Connection Management:

• Ensures proper setup, maintenance, and termination of connections in a network.

(c) Shannon’s Capacity:

• Defines the maximum data rate of a channel:
  $C = B \log_2(1 + S/N)$, where $B$ is bandwidth and $S/N$ is the signal-to-noise ratio.

(d) CSMA/CD (Carrier Sense Multiple Access with Collision Detection):

• A protocol used in Ethernet to detect and handle data collisions.

(e) Gateways:

• Devices that connect networks with different protocols, translating data formats.

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19. What is Congestion Control Algorithm? Explain with example.

Congestion control algorithms manage network traffic to avoid overloading and ensure smooth data flow.

Types:

1. Open Loop: Prevents congestion before it occurs (e.g., traffic shaping).
2. Closed Loop: Reacts to congestion (e.g., TCP congestion control).

Example:
TCP's Additive Increase Multiplicative Decrease (AIMD) adjusts the transmission rate based on feedback. If a packet loss is detected, the sender reduces its transmission rate.

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20. Explain Transport layer, Session layer, and Application layer.

Transport Layer:

• Provides reliable data delivery using protocols like TCP/UDP.
• Handles segmentation, error correction, and flow control.

Session Layer:

• Manages sessions between applications.
• Ensures synchronization and recovery.

Application Layer:

• Interfaces directly with user applications.
• Examples: HTTP, FTP, SMTP.

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 NOTE : 

•  This is an expected question answer which you have appeared in most of the exams. You will be able to study chapterwise most important topics as per your knowledge and will not be afraid of giving the paper. This is a great tool to improve your preparation.

•  The answers which are given in short cut or less words, here you can write and read them according to your understanding.