21. 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.
因为他不基于计时器
802.1D桥只中转根桥发出的BPDU信息
D. 802.1w bridges only relay BPDUs received from the root.
Answer: C
22. Which three of these statements about Dynamic Trunking Protocol are correct? (Choose three.) 对于动态中继协议，下面哪三个是正确的 A. It supports autonegotiation for both ISL and IEEE 802.1Q trunks.
支持在ISL协议和802.1Q协议的自动协商
B. It must be disabled on an interface if you do not want the interface to work as a trunk or start negotiation to become a trunk.
如果你不想让一个接口成为trunk或开始协商成trunk，那么必须禁用它
C. It is a point-to-multipoint protocol. D. It is a point-to-point protocol. 需要在一个点到点的协议上使用 E. It is not supported on private VLAN ports or tunneling ports.
Answer: ABD
23. 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
