单项选择题
Which command displays the CHAP authentication process as it occurs between two routers?（）
A. debug authentication B. debug chap ppp C. debug chap authentication D. debug ppp authentication
单项选择题 At which layer of the OSI model dose PPP perform?（）
单项选择题 Which command is used to display the collection of OSPF link states?（）
单项选择题 When you are troubleshooting an ACL issue on a router,which command can help you to verify which interfaces are affected by the ACL?（）
