请问ccnp642-813题库第193题的答案问题……?

great33

请问ccnp642-813题库第193题的答案问题？

此题答案是否应该为C

PS:题库答案写B??

Why is BPDU guard an effective way to prevent an unauthorized rogue switch from altering the spanningtree
topology of a network?
A. BPDU guard can guarantee proper selection of the root bridge.
B. BPDU guard can be utilized along with PortFast to shut down ports when a switch is connected to the
port.
C. BPDU guard can be utilized to prevent the switch from transmitting BPDUs and incorrectly altering the
root bridge election.
D. BPDU guard can be used to prevent invalid BPDUs from propagating throughout the network.
Answer: B
Explanation/Reference:
BPDU Guard只发不收BPDU，一旦收到BPDU，进入err-disabled。所以，可以有效防止非法接入的switc

晓__天

这题 就是 B C 说是的spanning tree guard root   

☆_._.‖_BU_、

kandlly

loverss

D是不是更恰当一些？新加入的交换机的bpdu不会被传播出去。
B中，如果新接入的交换机不启用STP，那也没有办法shutdown啊