思科认证CCIE考试模拟试题5
21. You are designing your network to be able to use trunks. As part of this process you are comparing the ISL and 802.1Q encapsulation options. All of these statements about the two encapsulation options are correct except which one?
你正在设计一个使用trunk的网络，你要比较使用ISL和802.1Q。对于这两种封装描述正确的 是哪个？
A. Both support normal and extended VLAN ranges.
B. ISL is a Cisco proprietary encapsulation method and 802.1Q is an IEEE standard.
C. ISL encapsulates the original frame.
D. Both support native VLANs.
Answer: D
22. You are about to migrate a customer network to use a VSS. Which of these statements is true about a VSS? 你要把网络升级为使用VSS,关于VSS的描述哪个是正确的
A. The VSS switch must be the root bridge for all VLANs and is automatically designated.
B. The VSS switch is defined in RFC 4318 as a managed object.
C. The PAgP+ or LACP protocols are used to maintain the operational state of the VSS devices.
PagP或LacP协议使用VSS设备
D. A VSS interoperates with a virtual port channel.
E. The 802.1Q or ISL protocols are used to maintain the operational state of the VSS devices.
F. A VSS increases the size of the spanning-tree domain.
Answer: C
23. You have done a partial migration from 802.1D STP to 802.1w STP. Which of the following is true? 你要升级生成树协议从802.1D到802.1W 下面哪个说的是对的
1. Spanning Tree Protocol calculates path cost based on which of these?
生成树中的计算成本值和哪个参数有关
A. interface bandwidth
B. interface delay
C. interface bandwidth and delay
D. hop count E. bridge priority
Answer: A
24. What two features in Cisco switches help prevent Layer 2 loops? (Choose two.)
那两个是CISCO交换机的2层防环的功能
A. UniDirectional Link Detection单向链路检测
B. Hot Standby Router Protocol
C. Virtual Router Redundancy Protocol
D. PortFast E. root guard F. loop guard环路保护
Answer: AF
25. Which of these correctly identifies a difference between the way BPDUs are handled by 802.1w and 802.1D? 哪个是在802.1W和802.1D协议对于BPDU信息的差异
A. 802.1D bridges do not relay BPDUs.
B. 802.1w bridges do not relay BPDUs.
C. 802.1D bridges only relay BPDUs received from the root.
D. 802.1w bridges only relay BPDUs received from the root.
Answer: C
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