As shown in the figure, RTA and RTB act as border routers between the BGP routing domain and the OSPF routing domain.
In order to realize the routing intercommunication between the BGP routing domain and the OSPF routing domain, the following route distribution strategy is not feasible: _______

IS-IS protocol messages are divided into IIH, CSNP, PSNP and LSP. These four message classifications are identified by ______.

The command to configure manual route aggregation of RIP protocol on MSR router is ___________.

There are 4 routes 10.0.0.0/24, 10.0.1.0/24, 10.0.2.0/24, and 10.0.3.0/24 in the routing table.
For route aggregation, the correct route after aggregation is _________.

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 ______.