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Catalyst 3750 SwitchSoftware Configuration Guide
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Chapter38 Configuring IP Unicast Routing
Configuring OSPF
its router ID, even if other interfaces have higher IP addresses. Because loopback interfaces never fail,
this provides greater stability. OSPF automatically prefers a loopback interface over other interfaces, and
it chooses the highest IP address among all loopback interfaces.
Beginning in privileged EXEC mode, follow these steps to configure a loopback interface:
Use the no interface loopback 0 global configuration command to disable the loopback interface.
Monitoring OSPF
You can display specific statistics such as the contents of IP routing tables, caches, and databases.
Table38-6 lists some of the privileged EXEC commands for displaying statistics. For more show ip ospf
database privileged EXEC command options and for explanations of fields in the resulting display, see
the Cisco IOS IP Command Reference, Volume 2 of 3: Routing Protocols, Release 12.2.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface loopback 0 Create a loopback interface, and enter interface configuration mode.
Step3 ip address address mask Assign an IP address to this interface.
Step4 end Return to privileged EXEC mode.
Step5 show ip interface Verify your entries.
Step6 copy running-config startup-config (Optional) Save your entries in the configuration file.
Table38-6 Show IP OSPF Statistics Commands
Command Purpose
show ip ospf [process-id] Display general information about OSPF routing
processes.
show ip ospf [process-id] database [router] [link-state-id]
show ip ospf [process-id] database [router] [self-originate]
show ip ospf [process-id] database [router] [adv-router [ip-address]]
show ip ospf [process-id] database [network] [link-state-id]
show ip ospf [process-id] database [summary] [link-state-id]
show ip ospf [process-id] database [asbr-summary] [link-state-id]
show ip ospf [process-id] database [external] [link-state-id]
show ip ospf [process-id area-id] database [database-summary]
Display lists of information related to the OSPF
database.
show ip ospf border-routes Display the internal OSPF routing ABR and ASBR
table entries.
show ip ospf interface [interface-name] Display OSPF-related interface information.
show ip ospf neighbor [interface-name] [neighbor-id] detail Display OSPF interface neighbor information.
show ip ospf virtual-links Display OSPF-related virtual links information.