for computer network course

Crop and straighten your question 1. Imagine that you have trained your St. Bemard, Bernie, to carry a box of theee 8-mm tapes instead of a flask of brandy. when your disk fils up, you consider that an emengency. these tapes each contain 7 Bigabytes. the dog can travel to your side, wherever you may be, at 18 kmyhour. For what range of distances does Bemie have a higher data rate than a transmission line whose data rate (excluding overhead) is 150 mbps? How does your answer change if 0) Bernie's speed is doubled; (Di) each tape capacity is doubled, (i) the data rate of the transmission line is doubled 2 Besides bandwidth and latency, what other parameter is needed to give agood characterization of the quality of service offered by a network used for lil digitined voice traffic? (i) video traffic? lii financial transaction traffic? 3 What are two reasons for using layered protocols? What is one possible disadvantage of using layered protocos? . A system has an n-layer protocol hierarchy. Applications generate messages of length M bytes. At each of the layers, an h-byte header is added. What fraction of the net-work bandwidth is filled with headers? Suppose the algorithms used to implement the operations at layer k is changed. How does this impact operations at layers k-1 and+1 6 Suppose there is a change in the service (set of operations) provided by layer k. How does this impact services at layers k-1 and k+1? 7. What are the five layers in the Internet protocol stack? What are the principal responsibilties of each of these layers? 8 Suppose Alice and Bob are sending packets to each other over a computer network. Suppose Trudy positions herself in the network so that she can capture all the packets sent by Alice and send whatever she wants to Bobs she can also capture all the packets sent by Bob and send whatever she wants to Alice. List some of the malicious things Trudy ean do from this position. 9 Suppose users share a 2 Mbps link. Also suppose each user transmits continuously at 1 Mbps when transmitting, but each user transmits only 20 percent of the time a. When circuit switching is used, how maay users can be supported b. For the remainder of this problem, suppose packet switching is used. Why will there be essentially no queuing delay before the link if two or fewer users transmit at the same time? Why will there be a queuing delay if three users transmit at the same time? c. Find the prohability that a given user is transmitting d. Suppose now there are three users. Find the probability that at any given time, all three users eously. Find the f time durin