Please show explanationf for the answers in S1 A1 and A2 Tha

Please show explanationf for the answers in S1, A1, and A2. Thanks

The figure below shows a client sending an HTTP request to Google and receiving and acknowledging the response Fill in the appropriate sequence numbers (seqno) and ACK numbers (ackno).

Solution

S1 : The value of S1 is the Initial sequence Number of Google’s web server. Each partner in the TCP connection selects its own starting sequence number. It is totally independent of the sequence number which client sent in the connection request.

A1: It is an Acknowledge number field which is calculated in following way:

Sequence Number In + Bytes of data received

Here sequence Number In = 1500 and Bytes of data received = 300 bytes

So the answer of A1 will be = 1500 + 300 = 1800

A2: Just like above the answer of A2 will be:

Here sequence Number In = S1 and Bytes of data received = 1400 bytes

So the answer of A1 will be = S1 + 1400