GATE CS 2015 Set 3 — Question 19

MCQ+1 / -0.33MediumTCP vs UDPTransport LayerComputer NetworksTCP Reliable Transfer

Computer Networks → Transport Layer → TCP Reliable Transfer

Last updated 5 September 2026

Question

Consider the following statements. I. TCP connections are full duplex II. TCP has no option for selective acknowledgement III. TCP connections are message streams

Correct answer (A) Only I is correct Solution Statement I: TCP is a full-duplex protocol, meaning data can be sent and received simultaneously on a single connection. This is correct. Statement II: TCP does have an option for Selective Acknowledgement (SACK), which allows the receiver to inform the sender about all segments that have been received successfully, so the sender only needs to retransmit the lost segments. The statement says it has 'no option', so it is incorrect. Statement III: TCP is a byte-stream oriented protocol, not a message-stream oriented protocol. UDP is message-oriented. So this statement is incorrect. Therefore, only statement I is correct. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (A) Only I is correct Solution Statement I: TCP is a full-duplex protocol, meaning data can be sent and received simultaneously on a single connection. This is correct. Statement II: TCP does have an option for Selective Acknowledgement (SACK), which allows the receiver to inform the sender about all segments that have been received successfully, so the sender only needs to retransmit the lost segments. The statement says it has 'no option', so it is incorrect. Statement III: TCP is a byte-stream oriented protocol, not a message-stream oriented protocol. UDP is message-oriented. So this statement is incorrect. Therefore, only statement I is correct.

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