An ACK number of 1000 in TCP always means that
- A. 999 bytes have been successfully received
- B. 1000 bytes have been successfully received
- C. 1001 bytes have been successfully received
- D. None of the above
Answer: A. 999 bytes have been successfully received
Explanation: ACK 1000 indicates expectation of byte 1000, meaning 0-999 (1000 bytes, if starting from 0) received. Wait, bytes are numbered. If ACK is 1000, it expects seq 1000. It acknowledges all bytes up to 999.