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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 42 Configuring IP Unicast Routing Configuring OSPF
When the neighbor relationships are reestablished, the NSF-capable stack master resynchronizes its
database with its NSF-aware neighbors, and routing information is exchanged between the OSPF
neighbors. The new stack master uses this routing information to remove stale routes, to update the
routing information database (RIB), and to update the forwarding information base (FIB) with the new
information. The OSPF protocols then fully converge.
Note OSPF NSF requires that all neighbor networking devices be NSF-aware. If an NSF-capable router
discovers non-NSF aware neighbors on a network segment, it disables NSF capabilities for that segment.
Other network segments where all devices are NSF-aware or NSF-capable continue to provide NSF
capabilities.
Use the nsf OSPF routing configuration command to enable OSPF NSF routing. Use the show ip ospf
privileged EXEC command to verify that it is enabled.
For more information, see the Cisco Nonstop Forwarding Feature Overview at this URL:
http://www.cisco.com/en/US/products/sw/iosswrel/ps1829/products_feature_guide09186a00800ab7fc.
html
Note NSF is not supported on interfaces configured for Hot Standby Router Protocol (HSRP).
Configuring Basic OSPF Parameters
Enabling OSPF requires that you create an OSPF routing process, specify the range of IP addresses to
be associated with the routing process, and assign area IDs to be associated with that range.
Beginning in privileged EXEC mode, follow these steps to enable OSPF:
To end an OSPF routing process, use the no router ospf process-id global configuration command.
This example shows how to configure an OSPF routing process and assign it a process number of 109:
Switch(config)# router ospf 109
Switch(config-router)# network 131.108.0.0 255.255.255.0 area 24
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 router ospf process-id Enable OSPF routing, and enter router configuration mode. The
process ID is an internally used identification parameter that is
locally assigned and can be any positive integer. Each OSPF
routing process has a unique value.
Step 3 nsf (Optional) Enable NSF operations for OSPF.
Step 4 network address wildcard-mask area area-id Define an interface on which OSPF runs and the area ID for that
interface. You can use the wildcard-mask to use a single
command to define one or more multiple interfaces to be
associated with a specific OSPF area. The area ID can be a
decimal value or an IP address.
Step 5 end Return to privileged EXEC mode.
Step 6 show ip protocols Verify your entries.
Step 7 copy running-config startup-config (Optional) Save your entries in the configuration file.