4.4 Which of the following statements are correct ?
A. (a) To provide a reliable network connectivity, many physical loops may exist in a bridged LAN (BLAN).
B. (b) No physical loop is allowed in a bridge LAN.
C. (c) Before transmitting frames, the spanning tree of a BLAN should be constructed first.
D. (d) Based on the spanning tree structure, there is only one communication path between each pair of bridges.
E. (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).
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4.5 What may happen if loops exist in a bridged LAN and the spanning tree is not established ?
A. (a) The receiver may receive duplicated frames.
B. (b) The bridges may learn wrong ports for MAC addresses.
C. (c) The frames will be filtered by bridges correctly.
D. (d) Each frame will be delivered to the destination via the shortest path between the source and destination stations.
4.6 Which bridge in a bridged LAN will become the “root bridge” of the spanning tree ?
A. (a) The bridge selected randomly
B. (b) The bridge with the largest bridge ID
C. (c) The bridge with the smallest bridge ID
D. (d) The bridge in the “center” of the bridged LAN
4.7 What is the “bridge ID” of a bridge in a bridged LAN ?
A. (a)6 bytes, MAC address of the bridge
B. (b)8 bytes, priority (2 bytes) + MAC address of the bridge (6 bytes)
C. (c)10 bytes, IP address (4 bytes) + MAC address of the bridge (6 bytes)
D. (d)6 bytes, priority (2 bytes) + IP address of the bridge (4 bytes)
4.8 Which of the following statements are correct about the ID of a bridge ?
A. (a) The ID is fixed
B. (b) The ID is programmable by setting MAC address
C. (c) The ID is programmable by setting priority value
D. (d) ID 1 > ID 2 if the MAC address of ID 1 > MAC address of ID 2.
E. (e) ID 1 > ID 2 if the priority value of ID 1 > the priority value of ID 2.
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