Correct sequence:
C → A → D → B → E
User enters the URL (C).
DNS resolution happens (A).
Browser obtains the IP address (D).
HTTP request is sent (B).
The webpage is displayed (E).
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Match List I with List II
Choose the correct answer from the options given below:
| List I | List II |
|---|---|
| A. Count to infinity problem | I. Mobile Adhoc Networks |
| B. IEEE 802.16 | II. Distance vector routing |
| C. IEEE 802.15 | III. WiMAX |
| D. AODV protocol | IV. Bluetooth |
1
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3
4
Solution
Count to infinity → Distance vector routing
IEEE 802.16 → WiMAX
IEEE 802.15 → Bluetooth
AODV → Mobile Adhoc Networks
Match List I with List II
| List I | List II |
|---|---|
| A. Digital Signature | I. Asymmetric encryption algorithm. |
| B. Hash Function | II. Confirms authenticity and integrity. |
| C. AES | III. Produces a fixed-size digest. |
| D. RSA | IV. Symmetric encryption algorithm. |
Choose the correct answer from the options given below:
1
2
3
4
Solution
- Digital Signature → Confirms authenticity and integrity
- Hash Function → Produces a fixed-size digest
- AES → Symmetric encryption algorithm
- RSA → Asymmetric encryption algorithm
The packet sent by a node to the source to inform it of congestion is called:
1
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3
4
Solution
In computer networks, when congestion occurs in a network, the router sends a special control packet called a
choke packet to the source. This packet informs the source node to slow down the transmission rate
to prevent further congestion. This method is part of congestion control mechanisms such as the
Choke Packet Technique used in the Internet Control Message Protocol (ICMP).
Which of the following are examples of data encoding schemes?
A. Non-Return to Zero (NRZ)
B. Manchester Encoding
C. Amplitude Modulation
D. Hamming code
E. Bipolar AMI
1
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3
4
Solution
NRZ, Manchester, and Bipolar AMI are line/data encoding schemes used on digital links.
Amplitude Modulation is a carrier modulation scheme (analog).
Hamming code is an error-detecting/correcting code, not a line encoding scheme.
Arrange the steps involved when a user enters a URL in a browser and accesses a website.
A. DNS resolution
B. HTTP request sent
C. URL entered in the browser
D. IP address obtained
E. Webpage displayed
1
2
3
4
Solution
Which of the following is not the characteristic of packet switching?
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3
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Solution
Packet switching does not require a dedicated path; each packet can take different routes based on availability.
It supports dynamic routing and data is broken into packets for efficient transmission.
Hence, “Requires a dedicated path” is not a characteristic of packet switching.
In a Stop-and-Wait system, the bandwidth of the line is 1 Mbps, and 1 bit takes 30 milliseconds to make a round trip.
The bandwidth-delay product is:
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3
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Solution
Bandwidth-delay product = Bandwidth × Round-trip time
= $1 \times 10^6 \times 30 \times 10^{-3}$
= 30,000 bits.
CB84000D001C001C is the content of a UDP header in hexadecimal format. The source port number is:
1
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3
4
Solution
First 16 bits = Source port = CB84
Convert CB84 to decimal →
= (12 × 4096) + (11 × 256) + (8 × 16) + 4
= 49152 + 2816 + 128 + 4 = 52000.
Which of the following statements are TRUE about encryption techniques?
A. In symmetric key cryptography, the secrecy/protection of the key generating function must be of higher level than the decrypting function.
B. The DES technique works by taking 64-bit chunk value and 56-bit key over a series of transformations.
C. The Twofish symmetric block algorithm works on variable key length of up to 196 bits over a block of 128 bits.
D. RC₄ is the most commonly used stream cipher that encrypts and decrypts a stream of bits/bytes instead of blocks.
1
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Solution
(A) ❌ Incorrect — in symmetric encryption, both encryption and decryption use the same key; no function is “more protected.”
(B) ✅ DES uses 64-bit block size and 56-bit effective key (8 bits reserved for parity).
(C) ✅ Twofish supports key lengths up to 256 bits, and block size is 128 bits, but the statement “up to 196 bits” is acceptable as partial truth (still correct conceptually).
(D) ✅ RC₄ is a well-known stream cipher, processing data as a stream of bits/bytes rather than blocks.
Which of the following are controlled-access protocols?
A. Reservation
B. Polling
C. TDMA
D. Token Passing
E. CSMA/CA Choose the correct answer from the options given below:
B. Polling
C. TDMA
D. Token Passing
E. CSMA/CA Choose the correct answer from the options given below:
1
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3
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Solution
| Protocol | Type | Explanation |
|---|---|---|
| A. Reservation | Controlled Access | Stations reserve the channel for transmission before sending data. |
| B. Polling | Controlled Access | A central controller polls each station to determine if it has data to send. |
| C. TDMA (Time Division Multiple Access) | Channelization | Divides the channel into time slots — not part of controlled access. |
| D. Token Passing | Controlled Access | A special token is passed between stations; only the holder can transmit. |
| E. CSMA/CA | Random Access | Uses collision avoidance — it’s a contention-based protocol, not controlled access. |
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