单项选择题
A. Nothing. The router is already suitable.
B. A BRI WAN interface in the router.
C. An external NT1 to terminate the local loop.
D. A TA/NT1 device on the router.
多项选择题 Which of the following can LCP successfully negotiate during the establishment of a PPP connection?（）
多项选择题 You are about to configure PPP n the interface of a Cisco router. Which authentication methods could you use?（）
单项选择题 Which of the following Frame-Relay encapsulation commands would you use, if you had to connect your Cisco router to a non-Cisco router?（）