Why are standards important for protocols?$$ It allows different types of devices to communicate with each other no matter where they are or what software they are running. It allows Mac$$s and Windows to communicate with each other and keeps everything consistent.$$

Describe the most popular wireless Internet access technologies today.$$ Compare and contrast them. Two of the most popular wireless Internet access today are Wi$-$Fi and $5$G$.$ Wi$-$Fi is used in a limited range but has a higher$-$speed internet connectivity in that range. $5$G can be used on your smart phones and on the go$.$ It often costs more and is normally slower than your at home Wi$-$Fi$.$

Suppose there is exactly one packet switch between a sending host and a$$ receiving host. The transmission rates between the sending host and the$$ switch and between the switch and the receiving host are R$1$ and R$2,$ respectively. Assuming that the switch uses store$-$and$-$forward packet switching,$$ what is the total end$-$to$-$end delay to send a packet of length L$?($Ignore queuing, propagation delay, and processing delay.$)$

Why will two ISPs at the same level of the hierarchy often peer with each$$ other? How does an IXP earn money?$$

Consider sending a packet from a source host to a destination host over a$$ fixed route. List the delay components in the end$-$to$-$end delay. Which of$$ these delays are constant and which are variable?$$

Suppose Host A wants to send a large file to Host B$.$ The path from Host A to Host$$ B has three links, of rates R$1=500$ kbps$,$ R$2=2$ Mbps$,$ and R$3=1$ Mbps$.$

$$a$.$ Assuming no other traffic in the network, what is the throughput for the$$ file transfer?

$$b$.$ Suppose the file is $4$ million bytes. Dividing the file size by the throughput, roughly how long will it take to transfer the file to Host B$?$

$$c$.$ Repeat $($a$)$ and $($b$),$ but now with R$2$ reduced to $100$ kbps$.$

What are the five layers in the Internet protocol stack? What are the principal$$ responsibilities of each of these layers?$$

Describe how a botnet can be created and how it can be used for a DDoS attack.$$

Review the car$-$caravan analogy in Section $1\mathrm{.}4.$ Assume a propagation speed$$ of $100$ km$/$hour$.$ a$.$ Suppose the caravan travels $175$ km$,$ beginning in front of one tollbooth,$$ passing through a second tollbooth, and finishing just after a third tollbooth. What is the end$-$to$-$end delay?$$ b$.$ Repeat $($a$),$ now assuming that there are eight cars in the caravan instead$$ of ten.$$