Regarding the DR/BDR election principle in the OSPF protocol, the following statement is wrong is ______.

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 2.2.2.2 0.0.0.0
RTB-ospf-1-area-0.0.0.0]network 20.0.0.0 0.0.0.255
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 default-route-advertise no-summarRTC-ospf-1-area-0.0.0.2]network
30.0.0.0 0.0.0.255
RTC-ospf-1]import-route direct
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]network 4.4.4.4 0.0.0.0
rtd-ospf-1-area-0.0.0.2]nssa
then there may not be injected _____ in zone 2

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

In the network shown in the figure, the default next hop of PTA is RTC, and the configuration of PBR is as follows:
policy-based-route pbr_a permit node 10
if-match acl 3000
appldefault output-interface serial 2/0
policy-based-route pbr_a dennode 20
According to the above configuration, what is wrong about the data stream matching Acl 3000 on the RTA?

SOA-based network architecture divides enterprise IT systems into which of the following layers? (Select one or more)