Which device might be installed at a branch office to enable and manage an IPsec site-to-site VPN?（）

单项选择题At which layer of the OSI model is RSTP used to prevent loops?（）

A. data link
B. network
C. physical
D. transport

单项选择题Which IPsec security protocol should be used when confidentiality is required?（）

A. PSK
B. AH
C. MD5
D. ESP

单项选择题which command allows you to verify the encapsulation type CISCO OR IETF for a frame relay link?（）

A. show frame-relay map
B. show frame-relay lmi
C. show inter serial
D. show frame-relay pvc

单项选择题What is the alternative notation for the IPV6 address B514:82C3:0000:0000:0029:EC7A:0000:EC72?（）

A. B514:82C3:0029::EC7A:0000:EC72
B. B514:82C3:0029:EC7A:EC72
C. B514:82C3::0029:EC7A:0:EC72
D. B514:82C3::0029:EC7A:EC72

单项选择题DNS servers provide what service?（）

A. They run a spell check on host names to ensure accurate routing
B. They convert domain names into IP address
C. Given an IP address,they determine the name of the host that is sought
D. They map individual hosts to their specific IP addresses