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4.4 Which of the following statements are correct? 下列有關橋接網路的敘述何者正確? |
| (a) To provide a reliable network connectivity, many physical loops may exist in a bridged LAN (BLAN). 為了提供網路穩定連結,橋接網路(BLAN) 拓樸可以存在一些迴圈. | |
| (b) No physical loop is allowed in a bridge LAN. 橋接網路拓樸不允許存在迴圈. | |
| (c) Before transmitting frames, the spanning tree of a BLAN should be constructed first. 在傳輸訊框以前,橋接網路的擴張樹必須先建立好. | |
| (d) Based on the spanning tree structure, there is only one communication path between each pair of bridges. 根據擴張樹的結構,任兩個橋接器之間只會有一個傳輸路徑. | |
| (e) For the spanning tree constructed by the IEEE 802.1D spanning tree algorithm, the communication path between each pair of bridges is optimized (shortest). 由IEEE 802.1D 擴張樹演算法所造出的擴張樹,任兩個橋接器之間的傳輸路徑一定最佳的 (最短的). |
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4.5 What may happen if loops exist in a bridged LAN and the spanning tree is not established ? 當橋接網路存在迴圈,且擴張樹尚未建立時,下列哪些狀況可能會發生? |
| (a) The receiver may receive duplicated frames. 接收者可能會重複收到訊框. | |
| (b) The bridges may learn wrong ports for MAC addresses. 橋接器可能會將MAC位址對應的隸屬埠學習錯誤. | |
| (c) The frames will be filtered by bridges correctly. 橋接器可以正確的過濾訊框. | |
| (d) Each frame will be delivered to the destination via the shortest path between the source and destination stations. 每個訊框都可以經由傳送端與接收端之間最短路徑來傳送. |
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4.6 Which bridge in a bridged LAN will become the “root bridge” of the spanning tree ? 橋接網路中的哪個橋接器將會成為擴張樹中的根橋接器 (root bridge) ? |
| (a) The bridge is selected randomly 該橋接器是隨機選取的 | |
| (b) The bridge with the largest bridge ID 擁有最大識別碼的橋接器 | |
| (c) The bridge with the smallest bridge ID擁有最小識別碼的橋接器 | |
| (d) The bridge in the “center” of the bridged LAN 位於橋接網路最中心位置的橋接器 |