单项选择题 A new router, named TK1, is being installed. You wish to add this router to your existing OSPF network. In doing so, you configure the following: TK1(config)# router ospf 1 TK1(config-router)# network 10.10.10.0 255.255.255.0 area 0 After making this change, you notice that the networks attached to TK1 are not being learned by the other OSPF routers. What could be the cause of this?（）

单项选择题 On your OSPF network, routers TK1 and TK2 belong to the same Ethernet network. However, they are unable to establish an adjacency over this link. While troubleshooting this problem, you issue the "show ip ospf interface Ethernet 0"command on each router. The output from these commands is displayed below: What is the underlying cause of the routers failing to become adjacent?（）

多项选择题 While trying to diagnose a routing problem in the network, you issue RIP debugging as displayed below: RtrA#debug ip rip Rip protocol debugging is on RtrA# 1d05h: RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0 (172.16.1.1) 1d05h: RIP: build update entries 1d05h: network 10.0.0.0 metric 1 1d05h: network 192.168.1.0 metric 2 1d05h: RIP: sending v1 update to 255.255.255.255 via Serial0/0 (10.0.8.1) 1d05h: RIP: build update entries 1d05h: network 172.16.0.0 metric 1 RtrA# 1d05h: RIP: received v1 update from 10.0.15.2 on Serial0/0 1d05h: 192.168.1.0 in 1 hops 1d05h: 192.168.0 in 16 hops (inaccessible) Based on the output of the above exhibit, which two of the following statements are true?（）