- ip ospf authentication
- ip osp f authentication-key
- ip ospf cost
- ip ospf dead-interval
- ip ospf hello-interval
- ip ospf message-digest-key
- ip ospf mtu-ignore
- ip ospf network
- ip ospf passive-interface
- ip osp f priority
- ip ospf retransmit-interval
- ip ospf shutdown
- ip ospf transmit-delay
- ip router ospf area
- ip router ospf multi- area
I Commands
This chapter describes the Cisco NX-OS Open Shortest Path First (OSPF) commands that begin with I.
ip ospf authentication
To specify the authentication type for an Open Shortest Path First (OSPF) interface, use the ip ospf authentication command. To remove the authentication type for an interface, use the no form of this command.
ip ospf authentication [ key-chain key-name | message-digest | null ]
Syntax Description
Command Default
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Usage Guidelines
Use the ip ospf authentication command to configure the authentication mode for an OSPF interface. If you use this command with no keywords, use the ip ospf authentication-key command to configure the password. If you use the message-digest keyword, use the ip ospf message-digest-key command to configure the message-digest key for the interface.
The authentication that you configure on an interface overrides the authentication that you configure for the area.
Examples
This example shows how to configure message-digest authentication:
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Saves the configuration changes to the startup configuration file. |
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Assigns a password to be used by neighboring routers that are using the password authentication of OSPF. |
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ip ospf authentication-key
To assign a password for simple password authentication to be used by neighboring Open Shortest Path First (OSPF) routers, use the ip ospf authentication-key command. To remove a previously assigned OSPF password, use the no form of this command.
ip ospf authentication-key [ 0 | 3 | 7 ] password
Syntax Description
(Optional) Configures a Cisco type 7 encrypted password string. |
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Any continuous string of characters that can be entered from the keyboard up to 8 bytes. |
Command Default
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Usage Guidelines
Use the ip ospf authentication-key command to configure a password for simple password authentication. The password created by this command is used as a key that is inserted directly into the OSPF header when Cisco NX-OS originates routing protocol packets. You can assign a separate password to each network on a per-interface basis. All neighboring routers on the same network must have the same password to be able to exchange OSPF information.
Note
Cisco NX-OS uses this key when you enable authentication for an interface with the ip ospf authentication interface configuration command or if you configure the area for authentication with the area authentication command in router configuration mode.
Examples
This example shows how to configure an unencrypted authentication key with the string yourpass:
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Saves the configuration changes to the startup configuration file. |
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ip ospf cost
To specify the cost of sending a packet on an interface, use the ip ospf cost command. To reset the path cost to the default, use the no form of this command.
no ip ospf cost interface-cost
Syntax Description
Unsigned integer value expressed as the link-state metric. The range is from 1 to 65535. |
Command Default
Calculates the cost based on the reference bandwidth divided by the configured interface bandwidth. You can configure the reference bandwidth or it defaults to 40 Gb/s.
Command Modes
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Usage Guidelines
Use the ip ospf cost command to configure the cost metric manually for each interface. This command overrides any settings for the reference bandwidth that you set using the reference-bandwidth command in router configuration mode.
If this command is not used, the link cost is calculated using the following formula:
Examples
This example shows how to configure the interface cost value to 65:
switch(config)# interface ethernet 1/2
switch(config-if)# ip ospf cost 65
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Specifies the reference bandwidth that OSPF uses to calculate the link cost. |
ip ospf dead-interval
To set the interval during which at least one hello packet must be received from a neighbor before the router declares that neighbor as down, use the ip ospf dead-interval command. To restore the default, use the no form of this command.
Syntax Description
Command Default
The default for seconds is four times the interval set by the ip ospf hello-interval command.
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Command History
Usage Guidelines
Use the ip ospf dead-interval command to set the dead interval that Open Shortest Path First (OSPF) advertises in hello packets. This value must be the same for all networking devices on a specific network.
Configure a shorter dead interval to detect down neighbors faster and improve convergence. Very short dead intervals could cause routing instability.
Use the show ip ospf interface command to verify the dead interval and hello interval.
Examples
This example shows how to set the OSPF dead interval to 20 seconds:
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Specifies the interval between hello packets that OSPF sends on the interface. |
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ip ospf hello-interval
To specify the interval between hello packets that Open Shortest Path First (OSPF) sends on the interface, use the ip ospf hello-interval command. To return to the default, use the no form of this command.
ip ospf hello-interval seconds
Syntax Description
Interval (in seconds). The value must be the same for all nodes on a specific network. The range is from 1 to 65535. |
Command Default
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Usage Guidelines
Use the ip ospf hello-interva l command to set the rate at which OSPF advertises hello packets. Shorter hello intervals allow OSPF to detect topological changes faster. This value must be the same for all routers and access servers on a specific network.
Examples
This example shows how to set the interval between hello packets to 15 seconds:
Related Commands
ip ospf message-digest-key
To enable Open Shortest Path First (OSPF) Message Digest 5 (MD5) authentication, use the ip ospf message-digest-key command. To remove an old MD5 key, use the no form of this command.
ip ospf message-digest-key key-id md5 [ 0 | 3 | 7 ] key
no ip ospf message-digest-key key-id
Syntax Description
Command Default
Command Modes
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Usage Guidelines
Use the ip ospf message-digest-key command when you configure the MD5 digest authentication mode. All neighbor routers must have the same key value on the network.
Examples
This example shows how to set key 19 with the password 8ry4222:
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Saves the configuration changes to the startup configuration file. |
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ip ospf mtu-ignore
To disable Open Shortest Path First (OSPF) maximum transmission unit (MTU) mismatch detection on received Database Descriptor (DBD) packets, use the ip ospf mtu-ignore command. To return to the default, use the no form of this command.
Syntax Description
Command Default
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Usage Guidelines
Use the ip ospf mtu-ignore command to disable MTU mismatch detection on an interface. By default, OSPF checks whether neighbors are using the same MTU on a common interface. If the receiving MTU is higher than the IP MTU configured on the incoming interface, OSPF does not establish adjacencies. Use the ip ospf mtu-ignore command to disable this check and allow adjacencies when the MTU value differs between OSPF neighbors.
Examples
This example shows how to disable MTU mismatch detection on received DBD packets:
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ip ospf network
To configure the Open Shortest Path First (OSPF) network type to a type other than the default for an interface, use the ip ospf network command. To return to the default, use the no form of this command.
ip ospf network { broadcast | point-to-point }
Syntax Description
Command Default
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Usage Guidelines
The network type influences the behavior of the OSPF interface. An OSPF network type is usually broadcast, which uses OSPF multicasting capabilities. Under this network type, a designated router and backup designated router are elected. For point-to-point networks, there are only two neighbors and multicast is not required. For routers on an interface to become neighbors, the network type for all should match.
This command overrides the medium { broadcast | p2p } command in interface configuration mode.
Examples
This example shows how to set an OSPF network as a broadcast network:
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ip ospf passive-interface
To suppress Open Shortest Path First (OSPF) routing updates on an interface, use the ip ospf passive-interface command. To return to the default, use the no form of this command.
Syntax Description
Command Default
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Usage Guidelines
If an interface is configured as a passive interface, it does not participate in OSPF and does not establish adjacencies or send routing updates. However, the interface is announced as part of the routing network.
Examples
This example shows how to set an interface as passive:
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ip ospf priority
To set the router priority for an Open Shortest Path First (OSPF) interface, use the ip ospf priority command. To return to the default, use the no form of this command.
no ip ospf priority number-value
Syntax Description
Number that specifies the priority of the router. The range is from 0 to 255. |
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Usage Guidelines
Use the ip ospf priority command to set the router priority, which determines the designated router for this network. When two routers are attached to a network, both attempt to become the designated router. The router with the higher router priority takes precedence. If there is a tie, the router with the higher router ID takes precedence. A router with a router priority set to zero cannot become the designated router or backup designated router.
Cisco Nexus 5500 uses this priority value when you configure OSPF for broadcast networks using the neighbor command in router configuration mode.
Examples
This example shows how to set the router priority value to 4:
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Configures the OSPF network type to a type other than the default for a given medium. |
ip ospf retransmit-interval
To specify the time between Open Shortest Path First (OSPF) link-state advertisement (LSA) retransmissions for adjacencies that belongs to the interface, use the ip ospf retransmit-interval command. To return to the default, use the no form of this command.
ip ospf retransmit-interval seconds
no ip ospf retransmit-interval
Syntax Description
Command Default
Command Modes
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Usage Guidelines
Use the ip ospf retransmit-interval command to set the time between LSA retransmissions. When a router sends an LSA to its neighbor, it keeps the LSA until it receives an acknowledgment message from the neighbor. If the router receives no acknowledgment within the retransmit interval, the local router resends the LSA.
Examples
This example shows how to set the retransmit interval value to 8 seconds:
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Saves the configuration changes to the startup configuration file. |
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ip ospf shutdown
To shut down an Open Shortest Path First (OSPF) interface, use the ip ospf shutdown command. To return to the default, use the no form of this command.
Syntax Description
Command Default
Command Modes
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Usage Guidelines
Use the ip ospf shutdown command to shut down OSPF on this interface.
Examples
This example shows how to shut down OSPF on an interface:
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Saves the configuration changes to the startup configuration file. |
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ip ospf transmit-delay
To set the estimated time required to send an Open Shortest Path First (OSPF) link-state update packet on the interface, use the ip ospf transmit-delay command. To return to the default, use the no form of this command.
ip ospf transmit-delay seconds
Syntax Description
Time (in seconds) required to send a link-state update. The range is from 1 to 450 seconds, and the default is 1. |
Command Default
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Usage Guidelines
Use the ip ospf transmit-delay command to set the estimated time needed to send an LSA update packet. OSPF increments the LSA age time by the transmit delay amount before transmitting the LSA update. You should take into account the transmission and propagation delays for the interface when you set this value.
Examples
This example shows how to set the transmit delay value to 8 seconds:
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Saves the configuration changes to the startup configuration file. |
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Sets the estimated time between LSAs transmitted from this interface. |
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ip router ospf area
To specify the Open Shortest Path First (OSPF) instance and area for an interface, use the ip router ospf area command. To return to the default, use the no form of this command.
ip router ospf instance-tag area area-id [ secondaries none ]
no ip router ospf instance-tag area area-id [ secondaries none ]
Syntax Description
Command Default
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Usage Guidelines
Use the ip router ospf area command to specify the area and OSPF instance for the interface.
Examples
This example shows how to configure an interface for OSPF:
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Saves the configuration changes to the startup configuration file. |
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ip router ospf multi-area
To configure a multi-area adjacency on an Open Shortest Path First (OSPF) interface, use the ip router ospf multi-area command. To return to the default, use the no form of this command.
ip router ospf instance-tag multi-area area-id
no ip router ospf instance-tag multi-area area-id
Syntax Description
Command Default
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Usage Guidelines
Before you use this command, make sure that you enable OSPF on the switch.
Examples
This example shows how to configure a multi-area adjacency:
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Saves the configuration changes to the startup configuration file. |
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