Configure OSPF Areas on the Router
Import information from other areas to learn their OSPF relationships. Perform this procedure to create normal, stubby, or not-so-stubby areas (NSSA).
Before you begin
Ensure that the VLAN exists if you configure OSPF on a VLAN.
You configure OSPF on a VRF instance the same way you configure the GlobalRouter, except that you must use VRF Router Configuration mode and the prefix ip ospf. The VRF must have an RP Trigger of OSPF. Not all parameters are configurable on non0 VRFs.
About this task
Place stubby or NSSAs at the edge of an OSPF routing domain. Ensure that you configure all routers in a stubby or NSSA as stubby or NSSA, respectively.
Procedure
Example
Create the OSPF area 192.0.2.10, and specify the area type as NSSA. Configure the area support to import summary advertisements into a stub area and configure the import external option for this area as stub. Ensure the configuration is correct.
Switch:1>enable Switch:1#configure terminal Switch:1(config)#router ospf Switch:1(config-ospf)#area 192.0.2.10 Switch:1(config-ospf)#area 192.0.2.10 import nssa Switch:1(config-ospf)#area 192.0.2.10 import stub Switch:1(config-ospf)#area 192.0.2.10 import-summaries enable Switch:1(config-ospf)#show ip ospf area
============================================================================================================================================ OSPF Area - GlobalRouter ============================================================================================================================================ AREA_ID STUB_AREA NSSA IMPORT_SUM ACTIVE_IFCNT NSSA TRANSLATOR NSSA TRANSLATOR NSSA TRANSLATOR NSSA TRANSLATOR ROLE STATE STABILITY INTERVAL EVENTS -------------------------------------------------------------------------------------------------------------------------------------------- 0.0.0.0 false false true 0 candidate disabled 40 0 STUB_COST INTRA_AREA_SPF_RUNS BDR_RTR_CNT ASBDR_RTR_CNT LSA_CNT LSACK_SUM -------------------------------------------------------------------------------------------------------------------------------------------- 0 0 0 0 0 0
Variable Definitions
The following table defines parameters for the area {A.B.C.D} command.
Variable |
Value |
---|---|
default-cost <0-16777215> |
Specifies the stub area default metric for this stub area, which is the cost from 0–16777215. This metric value applies at the indicated type of service. |
import <external|noexternal|nssa> |
Specifies the type of area:
|
import-summaries enable |
Configures the area support to import summary advertisements into a stub area. Use this variable only if the area is a stub area. |
stub |
Configures the import external option for this area as stub. A stub area has only one exit point (router interface) from the area. |
The following table defines parameters for the show ip ospf area command.
Variable |
Value |
---|---|
vrf WORD<1-16> |
Specifies a VRF. |
vrfids WORD<0-512> |
Specifies a range of VRF IDs. |