Example: The following command syntax will provide you with a wealth of relevant information regarding the OSPF processes that are currently running on your Cisco router. The entries in this output are defined in Table 8-1 that follows.
OSPF_ROUTER> show ip ospf Routing Process ospf 5774 with ID 126.96.36.199 Supports only single TOS (TOS0) routes It is an area border and autonomous system boundary router Summary Link update interval is 00:30:00 and the update due in 00:00:54 External Link update interval is 00:30:00 and the update due in 00:02:43 Redistributing External Routes from, connected with metric mapped to 100, includes subnets in redistribution bgp 5754 with metric mapped to 50, includes subnets in redistribution SPF schedule delay 5 secs, Hold time between two SPFs 10 secs Number of areas in this router is 2. 2 normal 0 stub Area BACKBONE(0) Number of interfaces in this area is 3 Area has no authentication SPF algorithm executed 9778 times Area ranges are 188.8.131.52/24 Active(1) Link State Update Interval is 00:30:00 and due in 00:02:43 Link State Age Interval is 00:20:00 and due in 00:02:43 Area 14 Number of interfaces in this area is 2 Area has no authentication SPF algorithm executed 30 times Area ranges are Link State Update Interval is 00:30:00 and due in 00:00:50 Link State Age Interval is 00:20:00 and due in 00:00:43
Table 8-1 describes some fields that are useful in a troubleshooting environment.
show ip ospf interface Command
You can gain an extensive amount of useful information from the show ip ospf interface command. In this use of the command, a specific interface was selected, but if used as shown here, then it will provide you with information on all interfaces. To display OSPF-related interface information, use the show ip ospf interface EXEC command. The syntax for this command is as follows:
show ip ospf interface [type number]
Usage Guidelines: You can verify that interfaces have been configured in the intended areas. In the example that follows, the serial interface has been placed in area 0.
The show ip ospf interface command also gives the timer intervals including the hello interval. These values must match if the OSPF routers are to become neighbors.
Example: The following is sample output from the show ip ospf interface command when Serial2/0.1 is specified.
OSPF_ROUTER# show ip ospf interface s2/0.1 Serial2/0.1 is up, line protocol is up Internet Address 184.108.40.206/27, Area 0 Process ID 5774, Router ID 220.127.116.11, Network Type BROADCAST, Cost: 64 Transmit Delay is 1 sec, State DROTHER, Priority 10 Designated Router (ID) 18.104.22.168, Interface address 22.214.171.124 Backup Designated router (ID) 126.96.36.199, Interface address 188.8.131.52 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:09 Neighbor Count is 8, Adjacent neighbor count is 2 Adjacent with neighbor 184.108.40.206 (Designated Router) Adjacent with neighbor 220.127.116.11 (Backup Designated Router)