GATE CS 2021 Set 2 — Question 17
Go beyond PYQs with Success TrackerAI-powered personalised practice and doubt support. Unlimited practice on eligible plans; AI usage limits apply.MCQ+1 / -0.33EasyTCP HandshakeTransport LayerComputer Networks
Computer Networks → Transport Layer → TCP Handshake
Last updated
Question
Consider the three-way handshake mechanism followed during TCP connection establishment between hosts and . Let and be two random 32-bit starting sequence numbers chosen by and respectively. Suppose sends a TCP connection request message to with a TCP segment having SYN bit = 1, SEQ number = , and ACK bit = 0. Suppose accepts the connection request. Which one of the following choices represents the information present in the TCP segment header that is sent by to ?
Correct answer
(C) SYN bit = 1, SEQ number = Y, ACK bit = 1, ACK number = X+1, FIN bit = 0
Solution
In the TCP three-way handshake process:
1.Host to Host (SYN): sends a segment with SYN = 1, ACK = 0, and its initial sequence number SEQ = .
2.Host to Host (SYN-ACK): responds by acknowledging 's request. It sets SYN = 1 and ACK = 1. It chooses its own initial sequence number SEQ = . The acknowledgment number (ACK number) is set to the next expected sequence number from , which is . Since this is not a connection termination, FIN = 0.
3.Host to Host (ACK): acknowledges 's segment by setting SYN = 0, ACK = 1, SEQ = , and ACK number = .
The question asks for the segment sent by to (step 2). This corresponds to SYN bit = 1, SEQ number = , ACK bit = 1, ACK number = , and FIN bit = 0. Thus, option (C) is correct.Continue learning with Success Tracker
A step still unclear? Work through it with support
Use Success Tracker to ask about the reasoning, then try another GATE CS question to check your understanding.
AI-powered practice· Unlimited practice on eligible plans
- PYQs with solutions
- Attempt available previous-year questions, then compare your reasoning with the worked solution. Coverage varies by stream.
- Practice that adapts
- Choose a topic, work on weaker areas and bookmark questions to revisit. Your attempts feed your progress tracking.
- AI doubt support
- Ask follow-up questions about a step or concept while practising, instead of stopping at the final answer.
Unlimited practice is available on eligible plans. Free practice and AI usage have limits; check the current plan allowances before choosing.
This page stays readable without an account. AI responses can be wrong; check them against the solution and source material.
More questions on Transport Layer
2026 Set 1 Q18With respect to a TCP connection between a client and a server, which one of the following…2026 Set 1 Q19Which of the following statements is/are true with respect to the interaction of a web browser with…2026 Set 2 Q21Consider a file of size 4 million bytes being transferred between two hosts connected via a path…2026 Set 2 Q22Which one of the following protocols may need to broadcast some of its messages?2026 Set 2 Q33If an IP network uses a subnet mask of 255.255.240.0, the maximum number of IP addresses that can…