Consider a TCP connection in a state where there are no outstanding ACKs. The…
2007
Consider a TCP connection in a state where there are no outstanding ACKs. The sender sends two segments back to back. The sequence numbers of the first and second segments are 230 and 290 respectively. The first segment was lost, but the second segment was received correctly by the receiver. Let X be the amount of data carried in the first segment (in bytes), and Y be the ACK number sent by the receiver. The values of X and Y (in that order) are
Answer: D. 60 and 230 — Step 1: Compute X: X = 290 − 230 = 60 bytes. Step 2: Determine the ACK number: The receiver did not get the segment starting at byte 230 (it was lost). TCP…
- A.
60 and 290
- B.
230 and 291
- C.
60 and 231
- D.
60 and 230
Attempted by 94 students.
Show answer & explanation
Correct answer: D
Step 1: Compute X: X = 290 − 230 = 60 bytes.
Step 2: Determine the ACK number: The receiver did not get the segment starting at byte 230 (it was lost). TCP uses cumulative ACKs, so the receiver will acknowledge the next expected byte, which is 230. Even though it received data starting at 290, it cannot advance the ACK past the missing data.
Answer: X = 60, Y = 230
A video solution is available for this question — log in and enroll to watch it.