課程影片與練習
課程簡介
第1週：網路架構與七層參考模式簡介
第2週：IEEE 802.3 乙太網路 (Ethernet)
第3週：IEEE 802.11 無線區域網路 (Wireless LAN)
※觀看影片請點擊影片名稱後方的"YOUTUBE"或"YOUKU"，
觀看YOUKU影片，請輸入密碼：mooc01004
第4週：IEEE 802.1D 交換機的擴張樹演算法 (Spanning Tree Algorithm)
第5週：IEEE 802.1Q 虛擬區域網路 (Virtual LAN)
第6週：區域網路可靠傳輸技術 －－ 滑動視窗技術
第7週：路由器運作原理以及網路互連技術
第8週：TCP 與網路阻塞偵測與控制技術
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3.2 Assume each of four nodes is able to send and receive signals that reach just the nodes to its immediate left and right. Suppose both A and C want to communicate with B and so they each send it a frame. Which of the following statements are correct for “hidden node problem” ?
設想下面四個節點都只能跟鄰近左右邊的點傳收訊息，假設現在A和C都想要跟B通訊，所以各自都對B送了一個訊框，下列哪些對於「隱藏節點問題」的敘述是正確的？
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| These two frames collide with each other at B 這兩個訊框「會」在 B 處碰撞 | |
| These two frames will NOT collide with each other at B 這兩個訊框「不會」在 B 處碰撞 | |
| Neither A nor C is aware of this collision A和C都不會察覺這次碰撞 | |
| Both A and C are aware of this collision A和C都會察覺這次碰撞 | |
| A and C are said to hidden nodes with respect to each other A 和 C 是彼此的隱藏節點 |
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3.3. For the following wireless configuration, which two nodes are hidden from each other ? Assume B can exchange frames with A and C, but it cannot reach D. And C can reach B and D but not A
下列無線網路配置中，哪兩個點是彼此的隱藏節點？假設 B 可以跟 A、C 交換訊框，但不行跟 D 通訊，而 C 可以和 B、D 通訊，但不行跟 A 通訊。
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| A and C | |
| A and D | |
| B and D | |
| B and C | |
| C and D |
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3.4. Assume each of four nodes is able to send and receive signals that reach just the nodes to its immediate left and right. Suppose B is sending a frame to A. Which of the following statements are correct for “exposed node problem” ?
設想下面四個節點都只能跟鄰近左右邊的節點傳收訊息，假設B正在送一個訊框給A，下列哪些對於「暴露節點問題」的敘述是正確的？
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| Although B and C are exposed to each other’s signals, there is no interference if B transmits to A while C transmits to D. 雖然 B 和 C 的訊號彼此暴露，但是 B 傳給 A 而 C 也同時傳給 D 時，A 跟 D 都可以成功收到訊框 (兩者並不會有衝撞) | |
| C cannot transmit to anyone because it can hear B’s transmission. C不能傳訊息給任何人，因為C聽到B正在傳輸 | |
| C is able to transmit to node D C可以傳送給D | |
| D is able to transmit to node C D可以傳送給C | |
| A is able to transmit to node B A可以傳送給B |
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3.5. For the following wireless configuration, which two nodes are exposed to each other ? Assume B can exchange frames with A and C, but it cannot reach D. And C can reach B and D but not A
下列無線網路的配置中，哪兩個節點彼此是對方的暴露節點？假設B可以跟A、C交換訊框，但是不能跟D通訊，C可以跟B、D通訊，但不能跟A通訊。
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| A and B | |
| A and C | |
| B and C | |
| B and D | |
| C and D |
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