Product guide

IP Routing Features
Contents
Not-So-Stubby-Area (NSSA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-49
Stub Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-50
OSPF RFC Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-50
Reducing AS External LSAs and Type-3 Summary LSAs . . . . . . . . . . 5-50
Algorithm for AS External LSA Reduction . . . . . . . . . . . . . . . . . . 5-51
Replacing Type-3 Summary LSAs and Type-7 Default External
LSAs with a Type-3 Default Route LSA . . . . . . . . . . . . . . . . . . . . . 5-52
Dynamic OSPF Activation and Configuration . . . . . . . . . . . . . . . . . . . 5-52
General Configuration Steps for OSPF . . . . . . . . . . . . . . . . . . . . . . . . . 5-53
Configuration Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-54
OSPF Global and Interface Settings . . . . . . . . . . . . . . . . . . . . . . . 5-54
Configuring OSPF on the Routing Switch . . . . . . . . . . . . . . . . . . . . . . 5-56
1. Enable IP Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-56
2. Enable Global OSPF Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-56
3. Changing the RFC 1583 OSPF Compliance Setting . . . . . . . . . 5-57
4. Assign the Routing Switch to OSPF Areas . . . . . . . . . . . . . . . . 5-59
5. Assign VLANs and/or Subnets to Each Area . . . . . . . . . . . . . . 5-64
6. Optional: Assigning Loopback Addresses to an Area . . . . . . . 5-65
Changing the Route Loop Prevention Method . . . . . . . . . . . . . . . . . . 5-33
7. Optional: Configure for External Route Redistribution in
an OSPF Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-67
8. Optional: Configure Ranges on an ABR To Reduce
Advertising to the Backbone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-70
9. Optional: Influence Route Choices by Changing the
Administrative Distance Default . . . . . . . . . . . . . . . . . . . . . . . . . . 5-73
10: Optional: Change OSPF Trap Generation Choices . . . . . . . . 5-74
11. Optional: Adjust Performance by Changing the VLAN
or Subnet Interface Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-75
12. Optional: Configuring OSPF Interface Authentication . . . . . . . . . 5-80
13. Configuring an ABR To Use a Virtual Link to the Backbone . . . . 5-82
Configuring a Virtual Link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-83
Optional: Adjust Virtual Link Performance by Changing
the Interface Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-85
Configuring OSPF Authentication on a Virtual Link . . . . . . . . . . 5-88
Displaying OSPF Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-90
Displaying General OSPF Configuration Information . . . . . . . . . 5-91
Displaying OSPF Area Information . . . . . . . . . . . . . . . . . . . . . . . . 5-92
5-3