$(8$ pts$)$ Pipelined network protocols are used every day by web browsers.

Describe how pipelining and window size are related? Describe in words why longer RTT$$s on a high capacity network link, $($over $1000$ Mbps$),$ will hinder a reliable data transfer protocol?

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$(10$ pts$)$ Suppose four large ftp file transfers are established over a $6$ Mbps WAN link. The only connections over this link are these four ftp sessions. The transmissions of the files start at the same time.

What approximate transmission rate will be given to each connection?

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Now suppose there are two ftp file streams between two different clients and two different servers established at the same exact time over the same link. One stream is using a $1460$ byte segment size the other a $576$ byte segment size. Assume there are no drops and both streams are using a standard TCP and IP header. Assume both ftp streams are copying the same $3$ MiB file $($using the binary MB unit$).$

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How many segments will be generated by the stream that is using the $1460$ byte segment size?

How many bytes of the file will be in the last segment?

How many segments will be generated by the stream that is using the $576$ byte segment size?

How many bytes of the file will be in the last segment of the second stream?

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$3.(4$ pts$)$ When developing a reliable data transfer protocol, why is it necessary to introduce timers?

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$(8$ pts$)$ The TCP protocol uses sequence numbers.

a$)$ What does the value of$$ a TCP sequence number represent?

b$)$ Provide three reasons why sequence numbers are required in TCP$?$

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$(12$ points$)$ Suppose client PC named X initiates a telnet session to a server called S$.$ At the same time a laptop client named Y initiates a telnet session to server S also. Provide possible source and destination port numbers for:

The segments sent from X to S The segments sent from Y to S The segments sent from S to X The segments sent from S to Y If X and Y are different hosts is it possible for them to both use the same source port number? If X and Y are the same host, is it possible for them to both user the same source port number?

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