MidTerm_Solution

MidTerm_Solution - 1) a) Solution 1: In TCP channel, ܴ...

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Unformatted text preview: 1) a) Solution 1: In TCP channel, ܴ ௔௩௘௥௔௚௘ ൌ ଴.଻ହ· ௐ ோ்் We have RTT ൌ 400ms, ܴ ௔௩௘௥௔௚௘ ൌ 4ܯܾ݌ݏ Buffer size we need: w ൌ ோ ೌೡ೐ೝೌ೒೐ ·ோ்் ଴.଻ହ ൌ ସMୠ୮ୱൈସ଴଴୫ୱ ଴.଻ହ ൎ 2.13¡bit Or Solution 2: In TCP channel, ܴ ௔௩௘௥௔௚௘ ൌ ௐ ோ்் We have RTT ൌ 400ms, ܴ ௔௩௘௥௔௚௘ ൌ 4ܯܾ݌ݏ Buffer size we need: w ൌ ܴ ௔௩௘௥௔௚௘ · ܴܶܶ ൌ 4¡bps ൈ 400ms ൎ 1.6¡bit (Whether or not to have 0.75 in the expression depends on how you model the TCP channel, here, we consider both are OK) b) The rate at which TCP sends data is a function of the congestion window and the current RTT. When the window size is w bytes and the current round ‐ trip time is RTT seconds, then TCP’s transmission rate is roughly ୵ r¢¢ . So during the i th RTT, we send W ୧ ൈ 500 bytes , as long as £ ౟ ൈହ଴଴ൈ଼ r¢¢ ൑ 2¡bps We have W ୧ ൌ W...
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This note was uploaded on 10/16/2011 for the course ELEC 308,315,10 taught by Professor Prof.shenghuisong during the Spring '11 term at CUHK.

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MidTerm_Solution - 1) a) Solution 1: In TCP channel, ܴ...

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