Question $1.)$ Suppose that a UDP segment needs to be sent with the segment composed of the

bits $11100110011001101101010101010101,$ which includes the header, but excludes the

checksum. Find the checksum to be included in the segment.

Choices:

a$.)0100010001000000$

b$.)0100010001000011$

c$.)0100010001000010$

d$.)0000010001000011$

Question $2.)$ Suppose that Bob sends $6$ segments to Alice. However, $2$ & $5$ segments are lost.

Assume that $N=3,RTT=10ms,$ and segment size $=1500$ bytes. Calculate the throughput in

the case of Go$-$back$-$N and Selective repeat.

Question $3.)$ Explain step$-$by$-$step all of the RDT $($Reliable Data Transfer$)$ versions, and, what

improvement that each RDT provides.

Question $4.)$ Consider a packet of length $2,000$ bytes. This packet travels from host $A,$ through a

link with length of $500$ km $,$ a router with queueing delay $2$ ms $,$ another link with length of $750$

km $,$ eventually to host $B.$ Here ms stands for millisecond. One millisecond is $0\mathrm{.}001$ second.

Suppose the propagation speed on both links is $2\mathrm{.}5108\frac{m}{s},$ the transmission rates of both

links are $10$ Mbps$.$ What is the total end$-$to$-$end delay from $A$ to $B$ in unit of ms $($millisecond$)?$

The derivation procedure is required. Must list all intermediate steps $($e$.$g$.,$ propagation delay.

transmission delay, router processing delay, router queueing delay, etc.$),$ calculation formula or

equations, and units $($such as bytes, bits, km$,$ m$,$ ms$,$ Mbps$,$ bps$,$ etc.$)$