单项选择题 A network administrator is trying to add a new router into an established OSPF network.The networks attached to the new router do not appear in the routing tables of the other OSPF routers.Given the information in the partial configuration shown below,what configuration error is causing this problem? （）Router(config)#router ospf 1Router(config-router)#network 10.0.0.0 255.0.0.0 area 0

单项选择题 Users on the 172.17.22.0 network cannot reach the server located on the 172.31.5.0 network.The network administrator connected to console port,issued the show ip route command,and was able to ping the server.Based on the output of the show ip route command topology shown in the graphic,what is the cause of the failure?（）

单项选择题 A router has two FastEthernet interfaces and needs to connect to four vlans in the local network.How can you accomplish this task,using the fewest physical interfaces and without decreasing network performance?（）