单项选择题
A.probe request/response， authentication request/response， association request/response
B.association request/response， authentication request/response， probe request/response
C.probe request/response， association request/response， authentication request/response
D.association request/response， probe request/response， authentication request/response
单项选择题 Refer to the exhibit. A Cisco Aironet Wireless LAN Client Adapter has been installed and configured through the ADU on the PC. The Aironet System Tray Utility （ASTU） has been enabled during the installation and the icon appears in the system tray area in the lower right of the desktop. What is thesignificance of the icon？（）
单项选择题 Refer to the exhibit. The command spanning-tree guard root is configured on interface Gi0/0 on both switch S2 and S5. The global configuration command spanning-tree uplinkfast has been configured on both switch S2 and S5. The link between switch S4 and S5 fails. Will Host A be able to reach Host B？（）
单项选择题 Refer to the exhibit. Which Virtual Router Redundancy Protocol （VRRP） statement is true about the roles of the master virtual router and the backup virtual router？（）