Refer to Figure $4-$ Screenshot from Wireshark. This screenshot shows a sequence of

segment exchanges between a http client and http server host machines. In particular,

lines $1$ to $3$ inclusive show the sequence of segments used to open a TCP connection

between a HTTP client $($port $52903)$ and a HTTP server $($port $80).$

Figure $4-$ Screenshot from Wireshark

$($a$)$ Identify the TCP messages used to open a connection and identify which line

numbers in figure $4$ relate to each of messages exchanged. In your answer,

identify which application has initiated the opening sequence, client or server,

justifying your answer with reference to the direction of the segment

transmissions.

$(8$ marks$)$

$($b$)$ Explain the purpose of the values contained in the following fields: Seq, Ack and

Win.

$(6$ marks$)$

$($c$)$ Do ACKs consume a sequence number? In consideration of this question,

identify the value in the Seq field contained in the segment carrying the HTTP

Request identified on line $4.$ Justify your answer with reference to previous

segment exchanges.

$(6$ marks$)$

$($d$)$ If the HTTP Request on line $4$ contains $100$ bytes, identify the ACK value stored

in a returning acknowledgment segment. Justify your answer.

$(5$ marks$)$