单项选择题
A. show frame-relay end-to-end
B. show frame-relay map
C. show frame-relay lmi
D. show frame-relay pvc
单项选择题 Which layer 2 protocol encapsulation type supports synchronous and asynchronous circuis and has built-in security mechanisms?（）
单项选择题 In which circumstance are multiple copies of the same unicast frame likely to be transmitted in a switched LAN?（）
单项选择题 Which command sets and automatically encrypts the privileged enable mode password?（）