单项选择题
Which device might be installed at a branch office to enable and manage an IPsec site-to-site VPN?（）
A. Cisco IOS IPsec/SSL VPN client B. Cisco VPN Clinet C. ISDN terminal adapter D. Cisco Adaptive Security Appliance
单项选择题 At which layer of the OSI model is RSTP used to prevent loops?（）
单项选择题 Which IPsec security protocol should be used when confidentiality is required?（）
单项选择题 which command allows you to verify the encapsulation type CISCO OR IETF for a frame relay link?（）
