$(5\%)$ Run Traceroute, TRACERT $($on Windows$),$ or another similar utility between a source and a destination in the country in which you reside. Do this at three different times of the day. Summarize your findings at each of the times with respect to the following, and explain your findings:

average and standard deviation of the round$-$trip delays

number of routers in the path

If you are not familiar with the utility, read the Microsoft article, $$How to Use TRACERT.$$

$1\mathrm{.}2(5\%)$ What are the five layers in the Internet protocol stack? Develop a table to summarise what each layer does.

$1\mathrm{.}3(5\%)$ What are packet$-$switched network and circuit$-$switched network, respectively? Develop a table to summarise their features, pros, and cons.

$1\mathrm{.}4(5\%)$ What are processing delay, queuing delay, transmission delay, and propagation delay, respectively? Where does each delay occur? What is traffic intensity? Why should the traffic intensity be no greater than one $(1)$ when designing a computer network?

$1\mathrm{.}5(5\%)$ What is Web$-$caching? When may Web$-$caching be more useful in a university? What problem does the conditional GET in HTTP aim to solve?

$1\mathrm{.}6(5\%)$ Suppose you have a Web$-$based email account, such as Gmail, and you have just sent a message to a friend, Alice, who accesses her mail from her mail server using IMAP. Assume that both you and Alice are using a smartphone to access emails via Wi$-$Fi at home. List all the network protocols that may be involved in sending and receiving the email. Discuss in detail how the message went from your smartphone to Alice$$s smartphone$$that is$,$ how the message went through all the network protocol layers on each of the network devices involved in the communication. Ignore everything between your ISP and Alice$$s ISP.

Part $2$: Long Answer Questions $(70\%)$

Solve the following network problems and show your work in detail.

$2\mathrm{.}1$

$(20\%)$ Consider that you are submitting your assignment in a compressed file from your computer at home to the university server that is hosting your online course. Your large file is segmented into smaller packets before it is sent into the first link. Each packet is $10,000$ bits long, including $100$ bits of header. Assume the size of the assignment file is $10$ MB$.$

How many packets will the assignment file be segmented into?

How many links can be identified using TRACERT or Traceroute between your computer and the university server? What are they?

What is the speed for each identified link based on your best calculation? Show your work.

Assume you start uploading the assignment at t$0.$ At what time will the last packet be pushed into the first link?

At what time will the last packet arrive at the university server?

$2\mathrm{.}2$

$(20\%)$ Consider that you are submitting another assignment from your home computer to the university server, and you have worked out a list of network links between your computer and the university server.

Based on your best estimate and calculation, what is the total distance your assignment data will travel to reach the university server?

Suppose the propagation speed over all the links is the same $2*10^8$ meters$/$sec$.$ What is propagation delay Tprop from your computer to the university server?

Further assume all the links have the same speed R bps$.$ What is the bandwidth$-$delay product R$*$Tprop$?$

Now suppose the assignment file is sent continuously as one big file. What is the maximum number of bits that will be in the links at any given time?

Based on the results from c and d$,$ what does the bandwidth$-$delay product imply?

$2\mathrm{.}3$

$(20\%)$ You have learned that a Web cache can be useful in some cases. In this problem, you will investigate how useful a Web cache can be at a home. First, you need to download Apache server and install and run it as a proxy server on a computer on your home network. Then, write a brief report on what you did to make it work and how you are using it on all your devices on your home network.

Assume your family has six members. Each member likes to download short videos from the Internet to watch on their personal devices. All these devices are connected to the Internet through Wi$-$Fi$.$ Further assume the average object size of each short video is $100$ MB and the average request rate from all devices to servers on the Internet is three requests per minute. Five seconds is the average amount of time it takes for the router on the ISP side of your Internet link to forward an HTTP request to a server on the Internet and receive a response.

What is the average time $\backslash$alpha for your home router to receive a video object from your ISP router?

What is the traffic intensity $$ on the Internet link to your home router if none of the requested videos is cached on the proxy server?

If average access delay $\backslash$beta is defined as $\backslash$alpha $/(\backslash$mu $1),$ what is the average access delay your family members will experience when watching the short videos?

If the total average response time is defined as $5+\backslash$beta $,$ and the miss rate of your proxy server is $0\mathrm{.}5,$ what will b