[Solved]Q2 Two Towns 20km Apart Connected Microwave Data Link Data Sent Across Link 800 Byte Frame Q37127725

Q2. (a) Two towns 20km apart are connected by a microwave data link. Data is sent across the link in 800 byte frames and the link operates at a data rate of 120Mbps. Assuming the link has a bit error rate of 4 x 10-5, and a velocity of propagation v-3 x 10% m/s, determine the link utilisation efficiency using the following protocols: 6 Marks] 13 marks] (i) Idle RQ (ii) Selective repeat RQ with a send window buffer k-2. (ii) Suggest a way to increase the link utilisation of the Selective repeat RQ 6 Marks) scheme. Discuss potential disadvantages of such an approach. b) The protocols in part (a) require 4-Byte acknowledgements (ACKs). For each of the three ARQ protocol cases in part (a) (i) Derive an expression for the round trip time (RTT) across the link, assuming processing times to be negligible with a send window [4 Marks] [4 Marks] buffer k-2 (i) Suggest a suitable RTT timeout value for each case. Hint: the timeout value 2 x RTT) (c) Most TCP algorithms assume that timeouts are caused by congestion. Why is this a problem when transmitting TCP connections over wireless channels? [4 Marks] Show transcribed image text Q2. (a) Two towns 20km apart are connected by a microwave data link. Data is sent across the link in 800 byte frames and the link operates at a data rate of 120Mbps. Assuming the link has a bit error rate of 4 x 10-5, and a velocity of propagation v-3 x 10% m/s, determine the link utilisation efficiency using the following protocols: 6 Marks] 13 marks] (i) Idle RQ (ii) Selective repeat RQ with a send window buffer k-2. (ii) Suggest a way to increase the link utilisation of the Selective repeat RQ 6 Marks) scheme. Discuss potential disadvantages of such an approach. b) The protocols in part (a) require 4-Byte acknowledgements (ACKs). For each of the three ARQ protocol cases in part (a) (i) Derive an expression for the round trip time (RTT) across the link, assuming processing times to be negligible with a send window [4 Marks] [4 Marks] buffer k-2 (i) Suggest a suitable RTT timeout value for each case. Hint: the timeout value 2 x RTT) (c) Most TCP algorithms assume that timeouts are caused by congestion. Why is this a problem when transmitting TCP connections over wireless channels? [4 Marks]

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Answer to Q2. (a) Two towns 20km apart are connected by a microwave data link. Data is sent across the link in 800 byte frames and… . . .