单项选择题
A.R1(config - router)# area 0 virtual - link 1.1.1.1 R3(config - router)# area 2 virtual - link 3.3.3.3
B.R1(config - router)# area 1 virtual - link 2.2.2.2 R3(config - router)# area 1 virtual - link 2.2.2.2
C.R1(config - router)# area 1 virtual - link 20.20 .20.2 R3(config - router)# area 1 virtual - link 30.30.30.2
D.R1(config - router)# area 1 virtual - link 30.30.30.3 R3(config - router)# area 1 virtual - link 20.20.20.1
E.R1(config - router)# area 1 virtual - link 3.3.3.3 R3(config - router)# area 1 virtual - link 1.1 .1.1
单项选择题 DR (Designated Router) is for environments where many routers on the same network such as Ethernet. In the following presented network, all routers are reloaded simultaneously, and DR is selected as expected. What is the RTC status?（）
多项选择题 What are two Cisco IOS commands that can be used to view neighbor adjacencies?（）
多项选择题 Which three are advantages to creating multiple areas in OSPF? (Choose three.) Select 3 response(s)？（）
