A PC that is communicating with a web server has a TCP window size of 6,000 bytes when sending data and a packet size of 1,500 bytes. Which byte of information will the web server acknowledge after it has received four packets of data from the PC?

Explanation & Hint:

In a TCP (Transmission Control Protocol) communication, the acknowledgment number that is sent by a receiver (in this case, the web server) indicates the next expected byte from the sender (the PC).

Given that each packet size is 1,500 bytes, after four packets, the total number of bytes sent would be $4\times 1,500=6,000$ bytes.

The acknowledgment sent by the receiver is for the next byte that it expects to receive. So, after successfully receiving 6,000 bytes, the next expected byte would be byte number 6,001.

Therefore, the web server will acknowledge byte number 6001 after it has received four packets of data from the PC.