Monitoring Troubleshooting an OSPF Network

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Table 8-2 describes some fields that are useful in a troubleshooting environment.

Table 8-2 show ip ospf int output definitions
Field Description

Serial The serial interface about which you requested information. The status of the physical link and operational status of protocol.
Internet Address Interface IP address, subnet mask, and area address
process ID OSPF process ID (ex: Autonomous System number), router ID, link-state cost
Transmit Delay Transmit delay, interface state (is it the DR or BDR?), and router priority to be used in determining the DR and BDR
Network Type Indicates the network type; in this case, broadcast
State DROTHER This command means that this router is not acting as either the Designated Router (DR) nor the Backup Designated Router (BDR). Both of these conditions are also possible in this field and these values are typically only seen on broadcast media.
Priority 10 This value indicates the priority of this router in the DR/BDR election. The default value is 1.
State DROTHER This command means that this router is acting as neither the Designated Router (DR) nor the Backup Designated Router (BDR). Both of these conditions are also possible in this field.
Designated Router Designated Router ID and its respective interface IP address
Backup Designated router Backup Designated Router ID and its respective interface IP address
Timer intervals configured Configuration of OSPF tunable timer intervals
Hello Number of seconds until next hello packet is sent out from this interface
Wait Indicates how long to wait if the Designated Router (DR) fails until the election process begins in order to replace the DR
Retransmit If a link-state retransmission list (flooded LSAs but not yet acknowledged) exists, this is the amount of time until it they are retransmitted.
Neighbor Count Count of network neighbors and list of adjacent neighbors
Adjacent neighbors Shows all routers that are adjacent to this one. This core router has two adjacencies, each of the ASBRs within an Autonomous System.

show ip ospf border-routers Command

To display the internal OSPF routing table entries to an Area Border Router (ABR) and Autonomous System Boundary Router (ASBR), use the show ip ospf border-routers privileged EXEC command.

Example:

    OSPF_ROUTER#show ip ospf border-routers    OSPF Process 5774 internal Routing Table    Codes: i - Intra-area route, I - Inter-area route    i 156.20.18.5 [64] via 156.20.18.1, Serial3/0.1, ASBR, Area 5, SPF 1020    i 56.88.5.17 [64] via 156.20.18.9, Serial3/0.2, ASBR, Area 5, SPF 1020    I 156.20.18.97 [128] via 156.20.16.40, Serial1/0.1, ASBR, Area 0, SPF    9819    I 156.20.18.97 [128] via 156.20.16.72, Serial2/0.1, ASBR, Area 0, SPF    9819    I 156.20.18.97 [128] via 156.20.16.41, Serial1/0.1, ASBR, Area 0, SPF    9819    I 156.20.18.97 [128] via 156.20.16.73, Serial2/0.1, ASBR, Area 0, SPF    9819    I 156.20.18.96 [128] via 156.20.16.40, Serial1/0.1, ASBR, Area 0, SPF    9819    I 156.20.18.96 [128] via 156.20.16.72, Serial2/0.1, ASBR, Area 0, SPF    9819    I 156.20.18.96 [128] via 156.20.16.41, Serial1/0.1, ASBR, Area 0, SPF    9819    I 156.20.18.96 [128] via 156.20.16.73, Serial2/0.1, ASBR, Area 0, SPF    9819    I 56.224.10.16 [128] via 156.20.16.36, Serial1/0.1, ASBR, Area 0, SPF    9819    I 56.224.10.16 [128] via 156.20.16.68, Serial2/0.1, ASBR, Area 0, SPF    9819    I 56.224.10.16 [128] via 156.20.16.38, Serial1/0.1, ASBR, Area 0, SPF    9819    I 56.224.10.16 [128] via 156.20.16.70, Serial2/0.1, ASBR, Area 0, SPF    9819    I 56.224.10.17 [128] via 156.20.16.36, Serial1/0.1, ASBR, Area 0, SPF    9819    I 56.224.10.17 [128] via 156.20.16.68, Serial2/0.1, ASBR, Area 0, SPF    9819    I 56.224.10.17 [128] via 156.20.16.38, Serial1/0.1, ASBR, Area 0, SPF    9819    I 56.224.10.17 [128] via 156.20.16.70, Serial2/0.1, ASBR, Area 0, SPF    9819 

Table 8-3 describes some fields that are useful in a troubleshooting environment.

Table 8-3 show ip ospf border-routers output definitions
Field Description

Rte Type The type of this route; it is either an intra-area or inter-area route
Destination Destination’s router ID
Next Hop Next hop toward the destination
Cost Cost of using this route
Type The router type of the destination; it is either an Area Border Router (ABR), an Autonomous System Boundary Router (ASBR), or both.
Area The area ID of the area from which this route is learned
SPF No The internal number of SPF calculation that installs this route

show ip ospf database Command

The show ip ospf database command displays the contents of the topological database maintained by the router. The command shows the router ID and the OSPF Process ID. The use of an easy-to-recognize router ID, such as a fictitious ID established for a loopback interface, can make troubleshooting more straightforward. Use the show ip ospf database EXEC command to display lists of information related to the OSPF database for a specific router. The various forms of this command deliver information about different OSPF link-state advertisements. The syntax for the various forms of the show ip ospf database EXEC command are as follows:

    show ip ospf [process-id area-id] database    show ip ospf [process-id area-id] database [router] [link-state-id]    show ip ospf [process-id area-id] database [network] [link-state-id]    show ip ospf [process-id area-id] database [summary] [link-state-id]    show ip ospf [process-id area-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] 


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OSPF Network Design Solutions
OSPF Network Design Solutions
ISBN: 1578700469
EAN: 2147483647
Year: 1998
Pages: 200
Authors: Tom Thomas

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