Multiple Choice Questions.
1.Initially suppose there is only one link between source and destination. Also suppose that message switching is used, with the message consisting of the entire MP3 file. The transmission delay Correct Answer 3 seconds 2.Referring to the above question, the end-to-end delay (transmission delay plus propagation delay) is Correct Answer:3.05 seconds 3.Referring to the above question, how many bits will the source have transmitted when the first bit arrives at the destination. Correct Answer:500,000 bits 4.Now suppose there are two links between source and destination, with one router connecting the two links. Each link is 5,000 km long. Again suppose the MP3 file is sent as one message. Suppose there is no congestion, so that the message is transmitted onto the second link as soon as the router receives the entire message. The end-to-end delay is Correct Answer:6.05 seconds 5.Now suppose that the MP3 file is broken into 3 packets, each of 10 Mbits. Ignore headers that may be added to these packets. Also ignore router processing delays. Assuming store and forward packet switching at the router, the total delay is Correct Answer:4.05 seconds 6.Now suppose there is only one link between source and destination, and there are 10 TDM channels in the link. The MP3 file is sent over one of the channels. The end-to-end delay is Correct Answer:30.05 seconds 7.Now suppose there is only one link between source and destination, and there are 10 FDM channels in the link. The MP3 file is sent over one of the channels. The end-to-end delay is Correct Answer:30.05 seconds8.Review the car-caravan example in Section 1.6. Again assume a propagation speed of 100 km/hour. Suppose the caravan travels 200 km, beginning in front of one tollbooth, passing through a second tollbooth, and finishing just before a third tollbooth. What is the end-to-end delay? Correct Answer:124 minutes 9.Referring to the above problem, suppose now that when a car arrives at the second tollbooth, it proceeds through the tollbooth without waiting for the cars behind it. What is the end-to-end delay? Correct Answer:122 minutes and 12 seconds 10.In this book we refer to a layer-4 PDU as a Correct Answer:segment True / False Questions 1.In a virtual-circuit packet-switched network, a packet switch maintains state information for each connection passing through the router. Answer:True
2.Before sending a packet into a datagram network, the source must determine all of the links that packet will traverse between source and destination. Answer:False 3.Layers four and five of the Internet protocol stack are implemented in the end systems but not in the routers in the network core. Answer:True 4.The Internet provides its applications two types of services, a TDM service and a FDM service. Answer:False 5.ADSL bandwidth is shared. Answer:False 6.With ADSL, each subscriber gets more downstream bandwidth than upstream bandwidth. Answer:True 7.Network News was present in the Internet before the emergence of the World Wide Web? Answer:True 8.The HTTP protocol was invented at Netscape in the early 1990s. Answer:False 9.Ethernet is a popular residential Internet access technology. Answer:False 10.Twisted-pair cooper wire is no longer present in computer networks. Answer:False More Questions / Answers for later Chapters will be introduced soon.