QUESTION 3 (14 marks) Answer the following questions concerning network utilisation and congestion. a) Explain the diffe

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Question 3 14 Marks Answer The Following Questions Concerning Network Utilisation And Congestion A Explain The Diffe 1 (157.66 KiB) Viewed 54 times

QUESTION 3 (14 marks) Answer the following questions concerning network utilisation and congestion. a) Explain the difference between flow control and congestion control, with reference to that part of an end-to-end telecommunication system that is running out of resources in each case. [2 marks] b) A "stop and wait" network transport protocol is used to transport 500 byte packets (including headers) at 100 Mbit/s over a network link that is 100 km long. Assuming the propagation speed is 0.7c, calculate the link utilisation assuming zero errors. (The speed of light, c, is 3 x 108 m/s.) [3 marks] c) Instead of the “stop and wait" protocol in b) above, consider use of a sliding window protocol using the same packet size, transmission rate, network bit rate and distance between sender and receiver. What is the minimum length (in bits) of the sequence number that would be necessary to support this protocol? Explain the reasoning behind your answer. [4 marks] d) Despite what you have calculated in part c), suppose the sequence number that is actually used is 4 bits long. What is the maximum link utilisation in the case of zero errors? Explain how you obtained your answer. [3 marks] e) Explain any difference in the delay sensitivity between the following two audiovisual streaming applications: i. A video-on-demand service such as Netflix ii. A video calling application such as Facetime. By directly relating your explanation to their delay requirements, explain the suitability of each service to use UDP or TCP Transport Protocols. [2 marks]