11-16
Ethernet Card Software Feature and Configuration Guide, R7.2
January 2009
Chapter 11 Configuring Networking Protocols
Configuring OSPF
Example 11-7 show ip ospf database and show ip ospf Privileged EXEC Command Ouputs
Router# show ip ospf database
OSPF Router with ID (192.168.3.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
192.168.2.1 192.168.2.1 428 0x80000003 0x004AB8 2
192.168.3.1 192.168.3.1 428 0x80000003 0x006499 2
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
192.168.2.2 192.168.3.1 428 0x80000001 0x00A4E0
Router# show ip ospf
Routing Process "ospf 1" with ID 192.168.3.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
Number of external LSA 0. Checksum Sum 0x000000
Number of opaque AS LSA 0. Checksum Sum 0x000000
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 2
Area has no authentication
SPF algorithm executed 4 times
Area ranges are
Number of LSA 3. Checksum Sum 0x015431
Number of opaque link LSA 0. Checksum Sum 0x000000
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0
Other OSPF Behavior Parameters
You can optionally configure other OSPF parameters in router configuration mode:
• Route summarization—When redistributing routes from other protocols, each route is advertised
individually in an external LSA. To help decrease the size of the OSPF link state database, you can
use the summary-address router configuration command to advertise a single router for all the
redistributed routes included in a specified network address and mask.
• Virtual links—In OSPF, all areas must be connected to a backbone area. You can establish a virtual
link in case of a backbone-continuity break by configuring two ABRs as endpoints of a virt ual link.
Configuration information includes the identity of the other virtual endpoint (the other ABR) and
the nonbackbone link that the two routers have in common (the transit area). Virtual links cannot be
configured through a stub area.
• Default route—When you specifically configure redistribution of routes into an OSPF routing
domain, the route automatically becomes an ASBR. You can force the ASBR to generate a default
route into the OSPF routing domain.