Configure OSPF Aggregate Area Ranges on the Router
Use aggregate area ranges to reduce the number of link-state advertisements required within the area. You can also control advertisements.
Before you begin
Enable OSPF globally.
Ensure that an area exists.
You configure OSPF area ranges 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.
Procedure
Example
Configure an OSPF area range to 192.0.2.2, configure the advertised metric cost to 10, and the advertisement mode to summarize.
Switch:1>enable Switch:1#configure terminal Switch:1(config)#router ospf Switch:1(config-ospf)# area range 192.0.2.2 255.255.255.0/32 summary-link Switch:1(config-ospf)# area range 192.0.2.2 255.255.255.0/32 summary-link advertise-metric 10 Switch:1(config-ospf)# area range 192.0.2.2 255.255.255.0/32 summary-link advertise-mode summarize
Variable definitions
The following table defines parameters for the area range command.
Variable |
Value |
---|---|
{A.B.C.D} {A.B.C.D/X} |
{A.B.C.D} identifies an OSPF area and {A.B.C.D/X} is the IP address and subnet mask of the range, respectively. |
advertise-metric <0-65535> |
Changes the advertised metric cost of the OSPF area range. |
advertise-mode <summarize|suppress|no-summarize> |
Changes the advertisement mode of the range. |
<summary-link|nssa-extlink> |
Specifies the link-state advertisement (LSA) type. If you configure the range as type nssa-extlink, you cannot configure the advertise-metric. |
The following table defines parameters for the show ip ospf area-range command.
Variable |
Value |
---|---|
vrf WORD<1-16> |
Specifies a VRF by name. |
vrfids WORD<0-512> |
Specifies a range of VRF IDs. |