M executes 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 _______.

In the topology shown in the figure, the network layer is reachable between RTA and RTB, and RTB and RTC.
Perform the following configuration on RTA, RTB and RTC respectively:
RTA]ospf 1
RTA-ospf-1]area 1
RTA-ospf-1-area-0.0.0.1]network 192.168.1.0 0.0.0.255
RTA-ospf-1-area-0.0.0.1]network 1.1.1.1 0.0.0.0
RTB]ospf 1
RTB-ospf-1]area 1
RTB-ospf-1-area-0.0.0.1]network 192.168.1.0 0.0.0.255
RTB-ospf-1-area-0.0.0.1]area 0
RTB-ospf-1-area-0.0.0.0]network 2.2.2.2 0.0.0.0
RTB-ospf-1-area-0.0.0.0]network 192.168.2.0 0.0.0.255
RTC]ospf 1
RTC-ospf-1]area 0
RTC-ospf-1-area-0.0.0.0]network 3.3.3.3 0.0.0.0
RTC-ospf-1-area-0.0.0.0]network 192.168.2.0 0.0.0.255
RTC-ospf-1]silent-interface all
The following statement is correct ________

As shown in the figure, RTA, RTB, and RTC run OSPF, and the process number is 100; OSPF process 200 runs between RTA, RTB, and RTD. The cost of all interconnected links is set to 10. Set the external route priority of OSPF 100 on RTA and RTB to 190, and import an external route 172.16.1.0/24 into OSPF 100 on RTC. RTA is set to redistribute OSPF100 routes to OSPF200, and RTB is set to redistribute OSPF200 routes to OSPF100. After the operation is stable, suppose that the external route 172.16.1.0/24 imported on the RTC disappears suddenly.
Based on the above scenario analysis, the correct description below is ______.

As shown in the figure, EBGP runs between AS100, AS200, AS300, and AS400.
When AS100 receives the BGP route sent by AS400, the path sequence recorded in its AS-Path attribute is ______

Regarding the Stub area and TotalStub area of the OSPF protocol, the following statement is wrong: ______