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8.25 Consider the following figure to demonstrate the growth of CongestionWindow size for different “packet lost” events in TCP congestion control. We can use the following three events to “describe” the curve in this figure. Initially, the connection is in slow start period with CongestionWindow size = 1 (1MSS). Event 1: 3-duplicate ACKs happens at 5th RTT Event 2: Timeout happens at 10th RTT Event 3: 3-duplicate ACKs happens again at 18th RTT. And we have a = 16 (window size), b = 8 (window size), c = 12 (window size), d = 6 (Threshold), e = 10 (window size), f = 5 (Threshold) as shown in the figure.
參考以下用來表示TCP壅塞控制機制中，對於發生不同的“封包遺失” 事件時, CongestionWindow 值的變化圖. 我們可以用下列三個事件來描述圖表上的曲線。起初，連線處於慢啟動階段而 CongestionWindow 值為 1 (1MSS). 事件 1: 三次重複回覆發生於 5th RTT 時間點 事件2: 逾時事件發生於10th RTT 時間點 事件3: 三次重複回覆再次發生於18th RTT 時間點 然後如圖所示, a = 16 (window size)，b = 8 (window size) ，c = 12 (window size), d = 6 (Threshold)， e = 10 (window size) ，f = 5 (Threshold)
Now, consider we have the following three events: Event 1: 3-duplicate ACKs happens at 4th RTT Event 2: Timeout happens at 17th RTT Event 3: 3-duplicate ACKs happens again at 25th RTT. Then we have 現在, 假設下列三個事件發生在不同時間點: 事件1: 三次重複回覆發生於 4th RTT 時間點 事件2: 逾時事件發生於17th RTT 時間點 事件3: 三次重複回覆再次發生於25th RTT時間點. 請問, a,b,c,d,e,f 的值各應該是多少 ? (請填入一個整數) 然後在下列的時間點時, CongestionWindow 值為何 ? (請填入一個整數)
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| a= | |
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| 於 3rd RTT 時間點 : | |
| 於 17th RTT時間點: | |
| 於 22th RTT 時間點: | |
| 於 30th RTT 時間點: | |
