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![]() Suppose that TCP's current estimated values for the round trip time (estimatedRTT) and deviation in the RTT (DevRTT) are 250 msec and 38 msec, respectively (see Section 3.5.3 for a discussion of these variables). Suppose that the next three measured values of the RTT are 280 msec, 200 msec, and 340 msec respectively. <image 1> Compute TCP's new value of DevRTT, estimatedRTT, and the TCP timeout value after each of these three measured RTT values is obtained. Use the values of = 0.125, and = 0.25. Round your answers to two decimal places after leading zeros. What is the estimatedRTT after the first RTT? | After the first RTT, the estimatedRTT is: 0.125 * (280 - 250) + 0.875 * 250 = 253.125 msec The DevRTT is: 0.25 * |280 - 253.125| + 0.75 * 38 = 41.875 msec The TCP Timeout value is: 253.125 + 4 * 41.875 = 415.5 msec After the second RTT, the estimatedRTT is: 0.125 * (200 - 253.125) + 0.875 * 253.125 = 239.062 msec The DevRTT is: 0.25 * |200 - 239.062| + 0.75 * 41.875 = 33.438 msec The TCP Timeout value is: 239.062 + 4 * 33.438 = 373.438 msec After the third RTT, the estimatedRTT is: 0.125 * (340 - 239.062) + 0.875 * 239.062 = 260.938 msec The DevRTT is: 0.25 * |340 - 260.938| + 0.75 * 33.438 = 44.062 msec The TCP Timeout value is: 260.938 + 4 * 44.062 = 433.938 msec Expected Answer: 253.75 Difficulty: Hard Subfield: Computer Network |
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