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.

ip ospf dead-interval seconds

no ip ospf dead-interval

Syntax Description

seconds
Interval (in seconds) during which the router must receive at least one hello packet from a neighbor or that neighbor adjacency is removed from the local router and does not participate in routing. The range is from 1 to 65535, and the default is 40. The value must be the same for all nodes on the network.

Command Default

The default for seconds is four times the interval set by the ip ospf hello-interval command.

Command Modes

Interface configuration mode

Command History

Release
Modification
5.0(3)N1(1)
This command was introduced.

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.

This command requires the LAN Base Services license.

Examples

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)#

Related Commands

Command
Description
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.