单项选择题
When configuring a serial interface on a router, what is the default encapsulation?（）
A. atm-dxi B. frame-relay C. hdlc D. lapb E. ppp
单项选择题 Which command displays CPU utilization?（）
单项选择题 Which command is used to debug a ping command?（）
单项选择题 Which command is used to see the path taken by packets across an IP network?（）
