Operating Environment
OS : Windows 11
VM : VMware® Workstation
Software：CML 2.7.2
Hardware：N/A
Network Topology
Why should you use area filtering whlie there is alreagy filtering with summarization?
If you need to 172.16.2.0/24 be present in area 0 but removed in area 34, you can not make it using filtering with summarization.
R3's OSPF routes before area filtering
R4's OSPF routes before area filtering
Sorry about that assign a wrong hostname, it should be R4.
Beacause ABRs with summarization filtering will transform Type 1 LSAs to Type 3 LSAs, so R3 won't transform 172.16.2.0/24 Type 3 summary LSAs to other areas' ones. Even we give it a try to configure summarization filtering in R3, it won't work.
Configure filtering with summarization in R3
Confirm configuration in show run output
There is no routes summarization in R4's routing table.
Area filtering configuration and confirmation
Since Area Filtering can filter inbond and outbound LSAs, so Let's make 172.16.1.0/24 romoved in area 0, make 172.16.2.0/24 be present in area 0 and romoved in area 34.
Area Filtering Configuration in R2
R3 - 172.16.1.0/24 removed in area 0
Area Filtering Configuration in R3
R4 - 172.16.2.0/24 removed in area 34
