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This chapter describes the Cisco NX-OS Open Shortest Path First (OSPF) commands that begin with D.
To set the interval during which at least one hello packet must be received from a neighbor on an Open Shortest Path First (OSPF) virtual link before the router declares that neighbor as down, use the dead interva l command. To restore the default, use the no form of this command.
Virtual link configuration mode
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Use the dead interval command in virtual link configuration mode to configure the dead interval advertised in OSPF hello packets. This value must be the same for all networking devices on the virtual link. The default value for seconds is four times the interval set by the hello-interval command.
You can configure a shorter dead interval ( seconds) to detect a down neighbor faster and improve convergence. A shorter dead interval may lead to virtual link instability by incorrectly declaring a slow neighbor as down.
Use the show ip ospf virtual-links command to verify the dead interval.
This example shows how to configure the OSPF dead interval to 20 seconds:
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Saves the configuration changes to the startup configuration file. |
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Specifies the interval between hello packets that Cisco NX-OS sends on the virtual link. |
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To generate a default external route into an Open Shortest Path First (OSPF) routing domain, use the default-information originate command. To disable this feature, use the no form of this command.
default-information originate [ always ] [ route-map map-name ]
no default-information originate [ always ] [ route-map map-name ]
Advertises the default route if the route is in the route table.
Address-family configuration mode
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Use the default-information originate command to assign a default route for redistributed routes. Whenever you use the redistribute command to redistribute routes into an OSPF routing domain, Cisco NX-OS automatically becomes an Autonomous System Boundary Router (ASBR). However, an ASBR does not, by default, generate a default route into the OSPF routing domain.
Use the route-map keyword to filter redistributed routes so that Cisco Nexus 6000 generates a default route only for routes that pass the route map. Use the always keyword to generate the default route regardless of whether the default route is in the route table.
Note The default-information originate command ignores match statements in the optional route map.
This example shows how to configure the default route redistributed into the OSPF routing domain for the Enhanced Interior Gateway Protocol (EIGRP):
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Saves the configuration changes to the startup configuration file. |
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To set default metric values for the Open Shortest Path First (OSPF) routing protocol, use the default-metric command. To return to the default state, use the no form of this command.
no default-metric metric-value
Default metric value appropriate for the specified routing protocol. The range is from 1 to 1677214. |
The metric for redistributed, connected, and static routes is set to 25.
Address-family configuration mode
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Use the default-metric command with the redistribute command to configure the same metric value for all redistributed routes except static and directly connected routes. A default metric helps to redistribute routes with incompatible metrics. Whenever external route metrics do not convert to an OSPF metric, use a default metric to enable the redistribution to proceed.
Note The default-metric command does not apply to the redistribution of directly connected routes into OSPF. Use a route map to change the default metric for directly connected routes.
This example shows how to configure OSPF to redistribute RIP and BGP and set the default metric to 10:
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Saves the configuration changes to the startup configuration file. |
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To define the Open Shortest Path First (OSPF) route administrative distance, use the distance command. To restore the default, use the no form of this command.
Administrative distance for all routes local to this OSPF process. The range is from 1 to 255. |
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Use the distance command to set a distance for an entire group of routes. Use the distance command when you configure multiple routing protocols, and you want to choose one set of routes over the other.
This example shows how to set the distance to 200, making the route less reliable:
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Saves this configuration change to the startup configuration file. |
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