CCNA系列认证CCNA(640-802)单项选择题每日一练(2019.11.11)

单项选择题
Which layer 2 protocol encapsulation type supports synchronous and asynchronous circuis and has built-in security mechanisms?（）
A. Frame Relay
B. HDLC
C. x.25
D. PPP
单项选择题
Acknowledgements, sequencing, and flow control are characteristics of which OSI layer?（）
A.Layer 2
B.Layer 3
C.Layer 4
D.Layer 5
E.Layer 6
F.Layer 7
单项选择题
Which IP address can be assigned to an Internet interface?（）
A. 10.180.48.224
B. 9.255.255.10
C. 192.168.20.223
D. 172.16.200.18
单项选择题
Which command encrypts all plaintext passwords?（）
A. Router(config)#password-encryption
B. Router(config)#service password-encryption
C. Router#service password-encryption
D. Router# password-encryption
单项选择题
Which command is used to see the path taken by packets across an IP network?（）
A. show ip route
B. show route
C. traceroute
D. trace ip route