The GATE Grind

GATE 2024 CS (CS1) – Question 29

Computer Networks · TCP: Flow Control, Congestion Control, Socket API · 1 mark · Multiple select

TCP client P successfully establishes a connection to TCP server Q. Let $N_P$ denote the sequence number in the SYN sent from P to Q. Let $N_Q$ denote the acknowledgement number in the SYN ACK from Q to P. Which of the following statements is/are CORRECT?

  1. The sequence number $N_P$ is chosen randomly by P
  2. The sequence number $N_P$ is always 0 for a new connection
  3. The acknowledgement number $N_Q$ is equal to $N_P$
  4. The acknowledgement number $N_Q$ is equal to $N_P+1$

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: (A) The sequence number $N_P$ is chosen randomly by P; (D) The acknowledgement number $N_Q$ is equal to $N_P+1$

Explanation

TCP uses a randomly chosen initial sequence number. The SYN consumes one sequence number, so the SYN-ACK acknowledgement number is N_P + 1.