单项选择题 Which of the following is true about an OSPF area border router (ABR)?（）

多项选择题 A router has been configured with the commands router os pf 9, network 172.16.1.0 0.0.0.255 area 8, and network 172.16.0.0 0.0.255.255 area 9, in that order. No other OSPF -related commands have been configured. The answers list the IP addresses that could be assigned to this routers Fa0/0 interface. Which an swers list an IP address/prefix length that would cause the router to put Fa0/0 into area 9?（）

多项选择题 Enterprise Router R1 connects an Enterprise to the Internet. R1 needs to create and advertise a default route into the Enterprise using EIGRP. The engineer creating the implementation plan has chosen to base this default route on the ip route command, rather than using i p default - network. Which of the following is not a useful step with this style of default route configuration?（）