Chapter 5: OSPF with Multiple Areas

Commands:

5.3.1 Configuring OSPF Routing

Router(config)# router ospf process-id
Router(config-router)# network network-address wild-card-mask area area-1-number
Router(config-router)# network network-address wild-card-mask area area-2-number

5.3.3 Configuring Route Summarization

On the ABR (Summarizes routes before injecting them into different area)
Router(config-router)# area area-id range network-address subnet-mask

On the ASBR (Summarizes external routes before injecting them into the OSPF domain.)
Router(config-router)# summary-address network-address subnet-mask

5.4.3 and 5.4.4 Configuring Stub Areas

The following command must be on all routers in that area, both ABR and internal routers:
Router(config-router)# area process-id stub

5.4.3 and 5.4.5 Totally Stubby Area

These commands must be on the ABR Router:
Router(config-router)# area area-id stub no-summary
Router(config)# ip route 0.0.0.0 0.0.0.0 next-hop-ip

The following command must be on all internal routers in that area:
Router(config-router)# area area-id stub

Router(config-router)# area process-id default-cost metric
Router(config-if)# bandwidth value

 

5.5.2 Virtual Links

Router(config-router)# area area-id virtual-link abr-ip-add

5.6.3 NSSA (Not So Stubby Area)

One of these commands must be on the ABR Router:
Router(config-router)# area area-id nssa
Router(config-router)# area area-id nssa default-information-originate

5.7.1 Show commands

Router#show ip ospf border-routers --- Displays the internal OSPF routing table entries to an ABR.
Router#show ip ospf virtual-links
Router#show ip ospf process-
Router#show ip ospf database
Router#show ip ospf [process-id area-id] database [router] Router#show ip ospf [process-id area-id] database [network] Router#show ip ospf [process-id area-id] database [summary] Router#show ip ospf [process-id area-id] database [asbr-summary] Router#show ip ospf [process-id area-id] database [external] Router#show ip ospf [process-id area-id] database [database-summary]