21. Totally stub, a special area of OSPF configuration experiment
1. Totally stub analysis of special area
Zone type function default route remarks commands stub filter LSA4, LSA5ABR default issue three types of default routes, seed cost value is 1 all routers in this area must be configured as stub, otherwise neighbors can not get up and cannot contain ASBR
Area 2 stub
Area 2 default-cost x
Totally stub filters three types of default routes issued by LSA3, LSA4 and LSA5ABR by default. The seed cost value is 1. All routers in this area must be configured as stub, otherwise neighbors cannot get up and cannot contain ASBRarea 2 stub no-summary.
2. Experimental topology
3. Experimental configuration
R1 configuration
Interface Loopback0
Ip address 1.1.1.1 255.255.255.0
Interface Serial0/0
Ip address 12.1.1.1 255.255.255.0
Router ospf 110
Router-id 1.1.1.1
Network 12.1.1.0 0.0.0.255 area 2
R2 configuration
Interface Loopback0
Ip address 2.2.2.2 255.255.255.0
Interface Serial0/0
Ip address 12.1.1.2 255.255.255.0
Interface Serial0/1
Ip address 23.1.1.2 255.255.255.0router ospf 110
Router-id 2.2.2.2
Network 12.1.1.0 0.0.0.255 area 2
Network 23.1.1.0 0.0.0.255 area 0
R3 configuration
Interface Loopback0
Ip address 3.3.3.3 255.255.255.0
Interface Serial0/0
Ip address 34.1.1.3 255.255.255.0
Interface Serial0/1
Ip address 23.1.1.3 255.255.255.0router ospf 110
Router-id 3.3.3.3
Network 23.1.1.0 0.0.0.255 area 0
Network 34.1.1.0 0.0.0.255 area 1
R4 configuration
Interface Loopback0
Ip address 4.4.4.4 255.255.255.0
Interface Serial0/0
Ip address 34.1.1.4 255.255.255.0
Interface Serial0/1
Ip address 45.1.1.4 255.255.255.0
Router ospf 110
Router-id 4.4.4.4
Redistribute rip subnets
Network 34.1.1.0 0.0.0.255 area 1
R5 configuration
Interface Loopback0
Ip address 5.5.5.5 255.255.255.0
Interface Serial0/1
Ip address 45.1.1.5 255.255.255.0
Serial restart-delay 0
Router rip
Version 2
Network 5.0.0.0
Network 45.0.0.0
No auto-summary
4. Experimental verification.
Filter LSA3, LSA4, LSA4
Before configuring totally stub
After configuring totally stub
ABR devolves three types of default routes
Before configuring totally stub
After configuring totally stub
