The force below shows a client sending an HTTP request to Go

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

Solution

When the sequence number of client is 1500, the acknowledgement number of the google\'s web server\'s acknowledgement number must have been the same before it received the payload shown in the diagram.

After the client sends the packets with seqno=1500, ackno=3500 with a payload of 300 bytes of data, the server (Google\'s web server) acknowledges the payload received and increases its acknowledgement number from 1500 to 1500+300 = 1800.

Also, its sequence number will be the same as the acknowledgement number of the client since the client had acknowledged the last packet it received from the server. Therefore, S1 = 3500.

After the client receives 1400 bytes of data, its acknowledgement number increases by 1400.

Therefore A2 = 3500+1400 = 4900

Hence,

S1 = 3500

A1 = 1800

A2 = 4900