Re-enabling OSPFv2 compatibility with RFC 1583

OSPFv2 is compatible with RFC 1583 and maintains a single best route to an autonomous system (AS) boundary router in the OSPF routing table. Disabling this compatibility causes the OSPF routing table to maintain multiple intra-AS paths, which helps prevent routing loops. You can re-enable OSPFv2 compatibility with RFC 1583 if it has been disabled.

Before you begin

Procedure

Enter the configure terminal command to access global configuration mode.
```
device# configure terminal
```
Enter the ip router ospf command to enter OSPF router configuration mode and enable OSPFv2 on the device.
```
device(config)# router ospf
```
Enter the rfc1583-compatibility command to re-enable OSPFv2 compatibility with RFC 1583.
```
device(config-router-ospf-vrf-default-vrf)# rfc1583-compatibility 
```

Example

The following example re-enables OSPFv2 compatibility with RFC 1583.

device# configure terminal
device(config)# router ospf 
device(config-router-ospf-vrf-default-vrf)# rfc1583-compatibility