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Working with Router Users

Troubleshooting OSPF Protocol: Show IP OSPF Command

Troubleshooting your Open Shortest Path First (OSPF) routing protocol is eased by the show ip ospf command which provides information specifically addressed to this protocol. Many options are available for the show ip ospf command.

These options are listed in the following output, followed by a discussion of a few of the key ones. Bear in mind that the results for some commands may lead you to seek specific information in other areas. For example, if you do not see neighbors, you may want to investigate why they are not showing up.

Router2#show ip ospf ?
  <1-65535>            Process ID number
  border-routers       Border and Boundary Router Information
  database             Database summary
  flood-list           Link state flood list
  interface            Interface information
  mpls                 MPLS related information
  neighbor             Neighbor list
  request-list         Link state request list
  retransmission-list  Link state retransmission list
  sham-links           Sham link information
  statistics           Various OSPF Statistics
  summary-address      Summary-address redistribution Information
  timers               OSPF timers information
  virtual-links        Virtual link information
  |                    Output modifiers

The first key command is show ip ospf, which shows basic configuration information related to the protocol and its operation. In this case, you see that the Process ID is 100, the router is only configured for one area, and the SPF algorithm has run twice on one LSA.

Router2#show ip ospf
 Routing Process "ospf 100" with ID
 Supports only single TOS(TOS0) routes
 Supports opaque LSA
 Supports Link-local Signaling (LLS)
 Initial SPF schedule delay 5000 msecs
 Minimum hold time between two consecutive SPFs 10000 msecs
 Maximum wait time between two consecutive SPFs 10000 msecs
 Incremental-SPF disabled
 Minimum LSA interval 5 secs
 Minimum LSA arrival 1000 msecs
 LSA group pacing timer 240 secs
 Interface flood pacing timer 33 msecs
 Retransmission pacing timer 66 msecs
 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) (Inactive)
        Number of interfaces in this area is 2 (1 loopback)
        Area has no authentication
        SPF algorithm last executed 00:06:37.652 ago
        SPF algorithm executed 2 times
        Area ranges are
        Number of LSA 1. Checksum Sum 0x006FFE
        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
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