1.
Application Layer
Q: What is the function of the Application Layer in the OSI model?
A:
The Application Layer is the topmost layer of the OSI model.
● It provides services directly to the user such as email, file transfer, and web browsing.
● Examples of protocols: HTTP, FTP, SMTP, DNS.
● It acts as the interface between the user and the network.
2. Local Area Network (LAN)
Q: What is a LAN?
A:
A Local Area Network (LAN) is a network that connects computers within a limited area such as
a building, office, or campus.
● High speed and low cost.
● Typically uses Ethernet or Wi-Fi.
● Example: Internet connection in a school computer lab.
3. IPv4 Address Length
Q: What is the length of an IPv4 address?
A:
● IPv4 address length is 32 bits (4 bytes).
● It is written in dotted-decimal notation, e.g., 192.168.1.1.
● Provides about 4.3 billion unique addresses.
4. Node
Q: Define a node in computer networks.
A:
A node is any device in a network that can send, receive, or forward data.
Examples: computer, printer, router, switch, server.
Each node has a unique identifier (MAC address or IP address).
5. Bit Rate
Q: What is bit rate?
A:
● Bit rate is the number of bits transmitted per unit time, measured in bps (bits per
second).
● Example: 1 Mbps = 1 million bits per second.
● Higher bit rate = faster data transfer.
6. Errors in Data Transmission
Q: What are the types of errors in data transmission?
A:
1. Single-bit error → Only one bit changes (0 → 1 or 1 → 0).
2. Burst error → Two or more consecutive bits change.
● Errors occur due to noise, interference, or weak signals.
7. Modes of Data Transmission
Q: Explain modes of data transmission.
A:
1. Simplex → One-way communication (TV broadcast).
2. Half-duplex → Two-way but one at a time (Walkie-talkie).
3. Full-duplex → Two-way simultaneously (Telephone).
8. Criteria of Effective Network
Q: What are the criteria for an effective and efficient network?
A:
1. Performance → Measured by throughput & delay.
2. Reliability → Ability to recover from failures.
3. Security → Protect data from unauthorized access.
4. Scalability → Easy to expand.
5. Availability → Should be accessible when needed.
9. Protocol Elements
Q: What are the key elements of a protocol?
A:
1. Syntax → Structure/format of data.
2. Semantics → Meaning of each field.
3. Timing → When data is sent and at what speed.
10. Circuit Switching vs Packet Switching
Q: Differentiate between circuit switching and packet switching.
A:
Feature Circuit Switching Packet Switching
Dedicated path established before Data broken into packets, each packet
Path
communication may take different path
Resource
Resources reserved for entire call Resources shared dynamically
Allocation
Efficiency Inefficient for bursty traffic Efficient for bursty traffic
Example Telephone network Internet
11. Types of Network
Q: Explain types of networks.
A:
1. LAN (Local Area Network) → Small area (office, school). High speed, low cost.
2. MAN (Metropolitan Area Network) → Covers a city/campus. Higher cost.
3. WAN (Wide Area Network) → Covers countries/continents. Example: Internet.
12. Redundancy
Q: What is redundancy in computer networks?
A:
Redundancy = duplication of critical components to ensure availability and reliability.
● Example: multiple routers, multiple servers.
● If one fails, backup takes over.
● Increases fault tolerance of a network.
