Execute the displaospf vlink command on the MSR router RTA, the router output is as follows:
OSPF Process 100 with Router ID 3.3.3.3
Virtual Links
Virtual-link Neighbor-ID -> 2.2.2.2, Neighbor-State: Full
Interface: 20.0.0.1 (GigabitEthernet0/1)
Cost: 1 State: P-2-P Tpe: Virtual
Transit Area: 0.0.0.1
Timers: Hello 10, Dead 40, Retransmit 5, Transmit Dela1
From the above output, you can judge _______.

A router has an interface that uses frame relay to connect to multiple routers, and now IS-IS needs to be run between these routers, what needs to be done on this interface?

In the topology shown in the figure, the correct IP addresses have been configured on RTA, RTB and RTC, and the network layer is reachable.

If OSPF neighbors need to be established between routers and routes are transmitted correctly, which of the following configurations is definitely feasible?

LSAs of type ______ are definitely not injected into the OSPF TotallStub area.

In the topology shown in the figure, the following configurations are performed on RTA, RTB, RTC and RTD respectively:
RTA-LoopBack0] ip address 1.1.1.1 255.255.255.255
RTA]ospf 1
RTA-ospf-1]area 1
RTA-ospf-1-area-0.0.0.1]network 10.0.0.0 0.0.0.255
RTA-ospf-1]import-route direct
RTB-LoopBack0] ip address 2.2.2.2 255.255.255.255
RTB]ospf 1
RTB-ospf-1]area 1
RTB-ospf-1-area-0.0.0.1]network 10.0.0.0 0.0.0.255
RTB-ospf-1-area-0.0.0.1]area 0
RTB-ospf-1-area-0.0.0.0]network 20.0.0.0 0.0.0.255
RTB-ospf-1]import-route direct
RTC-LoopBack0] ip address 3.3.3.3 255.255.255.255
RTC]ospf 1
RTC-ospf-1]area 0
RTC-ospf-1-area-0.0.0.0]network 20.0.0.0 0.0.0.255
RTC-ospf-1-area-0.0.0.0]area 2
RTC-ospf-1-area-0.0.0.2]nssa
RTC-ospf-1-area-0.0.0.2]network 30.0.0.0 0.0.0.255
RTC-ospf-1-area-0.0.0.2]network 3.3.3.3 0.0.0.0
RTD-LoopBack0] ip address 4.4.4.4 255.255.255.255
RTD]ospf 1
RTD-ospf-1]area 2
RTD-ospf-1-area-0.0.0.2]network 30.0.0.0 0.0.0.255
RTD-ospf-1-area-0.0.0.2]nssa
RTD-ospf-1]import-route direct
Which of the following routes may not exist in the RTD routing table ______.