CN PYQS 2026 MCQs
Q1A fully connected mesh network contains 8 nodes. Every pair of nodes requires a dedicated point-to-point link. How many links are required?
Explanation: For n nodes, links = n(n−1)/2 = 8×7/2 = 28.
Q2Wavelength Division Multiplexing is primarily associated with
Explanation: WDM combines multiple optical signals of different wavelengths over a single optical fiber.
Q3A communication code has minimum Hamming distance dmin = 5. What is the maximum number of errors that can be detected?
Explanation: A code with minimum Hamming distance dmin can detect up to dmin − 1 errors. Therefore, 5 − 1 = 4.
Q4A sender transmits frame 5 but does not receive its acknowledgement within the timeout interval. Assume the frame or its acknowledgement has been lost. What should the sender do?
Explanation: When an acknowledgement is not received before timeout, the sender retransmits the unacknowledged frame.
Q5Which statement correctly distinguishes IPv6 from IPv4?
Explanation: IPv6 uses 128-bit IP addresses, whereas IPv4 uses 32-bit IP addresses.
Q6Host A knows the IP address of Host B, and both hosts are on the same LAN. Host A does not have Host B's MAC address in its ARP cache. What happens first?
Explanation: Host A broadcasts an ARP request to find the MAC address associated with Host B's IP address.
Q7An application requires reliable, ordered delivery with retransmission of lost data. Which transport protocol is more appropriate?
Explanation: TCP provides reliable, ordered delivery and retransmits lost data.
Q8A client wants to access www.example.com but does not know its IP address. Which application-layer service is responsible for resolving the domain name?
Explanation: DNS resolves domain names such as www.example.com into IP addresses.
Q9Consider the following TCP exchange: (i) Client → Server: SYN, (ii) Server → Client: SYN + ACK, (iii) Client → Server: ACK. What is the purpose of this exchange?
Explanation: SYN, SYN+ACK, and ACK form the TCP three-way handshake used to establish a connection.
Q10A web browser sends a request to a web server and receives a response containing the requested resource. Which communication model is primarily illustrated?
Explanation: The client sends a request and the server sends a response, which is the request-response communication model.