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This chapter describes the Cisco NX-OS Open Shortest Path First (OSPF) commands that begin with I.
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]
no ip ospf authentication
No authentication
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
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.
This command requires the LAN Base Services license.
This example shows how to configure message-digest authentication:
switch(config)# interface ethernet 2/1
switch(config-if)# no switchport
switch(config-if)# ip ospf authentication message-digest
switch(config-if)# ip ospf message-digest-key 33 md5 0 mypassword
switch(config-if)#
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
no ip ospf authentication-key
Unencrypted password
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
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.
This command requires the LAN Base Services license.
This example shows how to configure an unencrypted authentication key with the string yourpass:
switch(config)# interface ethernet 1/5
switch(config-if)# no switchport
switch(config-if)# ip ospf authentication-key yourpass
switch(config-if)#
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.
ip ospf cost interface-cost
no ip ospf cost interface-cost
interface-cost |
Unsigned integer value expressed as the link-state metric. The range is from 1 to 65535. |
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.
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
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:
link cost = reference bandwidth / interface bandwidth
This command requires the LAN Base Services license.
This example shows how to configure the interface cost value to 65:
switch(config)#
interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)#
ip ospf cost 65
switch(config-if)#
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reference-bandwidth |
Specifies the reference bandwidth that OSPF uses to calculate the link cost. |
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.
ip ospf dead-interval seconds
no ip ospf dead-interval
The default for seconds is four times the interval set by the ip ospf hello-interval command.
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
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.
This command requires the LAN Base Services license.
This example shows how to set the OSPF dead interval to 20 seconds:
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip ospf dead-interval 20
switch(config-if)#
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ip ospf hello-interval |
Specifies the interval between hello packets that OSPF sends on the interface. |
show ip ospf interface |
Displays OSPF interface-related information. |
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
no ip ospf hello-interval
seconds |
Interval (in seconds). The value must be the same for all nodes on a specific network. The range is from 1 to 65535. |
10 seconds
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
Use the ip ospf hello-interval 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.
This command requires the LAN Base Services license.
This example shows how to set the interval between hello packets to 15 seconds:
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip ospf hello-interval 15
switch(config-if)#
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
Unencrypted
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
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.
This command requires the LAN Base Services license.
This example shows how to set key 19 with the password 8ry4222:
switch# configure terminal
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip ospf message-digest-key 19 md5 8ry4222
switch(config-if)#
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.
ip ospf mtu-ignore
no ip ospf mtu-ignore
This command has no arguments or keywords.
OSPF MTU mismatch detection is enabled.
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
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.
This command requires the LAN Base Services license.
This example shows how to disable MTU mismatch detection on received DBD packets:
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip ospf mtu-ignore
switch(config-if)#
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show ip ospf |
Displays general information about OSPF routing instances. |
show ip ospf interface |
Displays OSPF-related interface information. |
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}
no ip ospf network
broadcast |
Sets the network type as broadcast. |
point-to-point |
Sets the network type as point-to-point. |
Depends on the network type.
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
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.
This command requires the LAN Base Services license.
This example shows how to set an OSPF network as a broadcast network:
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip address 192.0.2.33 255.255.255.0
switch(config-if)# ip ospf network broadcast
switch(config-if)#
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show ip ospf |
Displays general information about OSPF routing instances. |
show ip ospf interface |
Displays OSPF-related interface information. |
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.
ip ospf passive-interface
no ip ospf passive-interface
This command has no arguments or keywords.
Disabled
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
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.
This command requires the LAN Base Services license.
This example shows how to set an interface as passive:
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip ospf passive-interface
switch(config-if)#
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show ip ospf |
Displays general information about OSPF routing instances. |
show ip ospf interface |
Displays OSPF-related interface information. |
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.
ip ospf priority number-value
no ip ospf priority number-value
number-value |
Number that specifies the priority of the router. The range is from 0 to 255. |
Priority of 1
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
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 6000 uses this priority value when you configure OSPF for broadcast networks using the neighbor command in router configuration mode.
This command requires the LAN Base Services license.
This example shows how to set the router priority value to 4:
switch# configure terminal
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip ospf priority 4
switch(config-if)#
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ip ospf network |
Configures the OSPF network type to a type other than the default for a given medium. |
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
5 seconds
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
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.
This command requires the LAN Base Services license.
This example shows how to set the retransmit interval value to 8 seconds:
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip ospf retransmit-interval 8
switch(config-if)#
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.
ip ospf shutdown
no ip ospf shutdown
This command has no arguments or keywords.
None
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
Use the ip ospf shutdown command to shut down OSPF on this interface.
This command requires the LAN Base Services license.
This example shows how to shut down OSPF on an interface:
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip ospf shutdown
switch(config-if)#
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copy running-config startup-config |
Saves the configuration changes to the startup configuration file. |
show ip ospf |
Displays OSPF information. |
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
no ip ospf transmit-delay
seconds |
Time (in seconds) required to send a link-state update. The range is from 1 to 450 seconds, and the default is 1. |
1 second
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
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.
This command requires the LAN Base Services license.
This example shows how to set the transmit delay value to 8 seconds:
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip ospf transmit-delay 8
switch(config-if)#
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]
10 seconds
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
Use the ip router ospf area command to specify the area and OSPF instance for the interface.
This command requires the LAN Base Services license.
This example shows how to configure an interface for OSPF:
switch# configure terminal
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip router ospf Base area 33
switch(config-if)#
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copy running-config startup-config |
Saves the configuration changes to the startup configuration file. |
show ip ospf interface |
Displays OSPF interface-related information. |
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
None
Interface configuration mode
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6.0(2)N1(1) |
This command was introduced. |
Before you use this command, make sure that you enable OSPF on the switch.
This command requires the LAN Base Services license.
This example shows how to configure a multi-area adjacency:
switch# configure terminal
switch(config)# interface ethernet 1/2
switch(config-if)# no switchport
switch(config-if)# ip router ospf Base area 33
switch(config-if)# ip router ospf Base multi-area 99
switch(config-if)#