Using Wildcard Masks with OSPF Areas
When compared to an IP address, a wildcard mask identifies which addresses get matched for placement into an area:
- A 0 (zero) in a wildcard mask means to check the corresponding bit in the address for an exact match.
- A 1 (one) in a wildcard mask means to ignore the corresponding bit in the address—can be either 1 or 0.
TIP: An octet of all 0s means that the octet has to match exactly to the address. An octet of all 1s means that the octet can be ignored.
Configuring OSPF: Optional Commands
The following commands, although not mandatory, enable you to have a more controlled and efficient deployment of OSPF in your network.
Loopback Interfaces
Router ID
DR/BDR Elections
Modifying Cost Metrics
Authentication: Simple
Authentication: Using MD5 Encryption
Timers
Propagating a Default Route
Verifying OSPF Configuration
Troubleshooting OSPF
