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igp-advertise-holddown
Configures the delay in the removal of IGP advertisement due to TE tunnel instability.
Syntax: igp-advertise-holddown delayTime
no igp-advertise-holddown
delayTime
Specifies the number of seconds or milliseconds to delay the removal of IGP advertisement due to TE tunnel instability.
Valid values are 0.0 to 4294967.00 0 <s | ms> where s is seconds and ms is milliseconds.
Description: When type igp-advertise is enabled at the tunnel ingress, the tunnel egress is seen by the IGP edge router as an operational adjacency. When an LSP goes down, you want to provide enough time for tunnel resilience to establish a new LSP, thereby avoiding BGP synchronization. There may be a minimal interval of lost data while ingress LSRs reconverge affected LSPs, but the total elapsed time will represent a substantial improvement over the need for the BGP resynchronization that would be required in the absence of this feature. Should the LSP to this egress fail to reestablish, removal of the IGP advertisement is required to prevent further loss of data. When the igp-advertise-holddown timer expires, the IGP advertisement for the affected egress is removed. The igp-advertise-holddown timer should be set to ensure that enough time is provided for resilience to establish a new path, but not so long a time that, should resilience fail to establish a new path, data continues to be needlessly lost.
The hold-down timer is activated when a tunnel failure takes place. The timer must account for both the time it takes for resilience to activate plus the time it takes for network reconvergence. Depending upon the complexity of the network, reconvergence can be anywhere from 300ms to 5s. As a general rule setting the timer for the configured resilience time plus 5s is sufficient for the timer to be effective.
Use the igp-advertise-holddown command to configure the delay associated with the removal of IGP advertisements due to an LSP failure.
Use the no igp-advertise-holddown command to reset the default value for this command.
Factory Default: 10s.
Command Mode: Traffic engineering parameter-set and traffic engineering tunnel-name.
Example 1: The following example configures tunnel defaults to enable type igp-advertise and set the igp-advertise-holddown timer for 8 seconds:
router>enable
router#configure terminal
router(config)#mpls traffic-engineering isis
router(config-te)#tunnel default
router(config-te-tunnel-param)#type igp-advertise
router(config-te-tunnel-param)#igp-advertise-holddown 8
router(config-te-tunnel-param)#exit
router(config-te)#
Example 2: The following example resets the default value for the igp-advertise-holddown timer:
router>enable
router#configure terminal
router(config)#mpls traffic-engineering isis
router(config-te)#tunnel default
router(config-te-tunnel-param)#no igp-advertise-holddown
router(config-te-tunnel-param)#exit
router(config-te)#
Related Commands: type igp-advertise
show mpls te tunnel
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Source
File Name: TE%20Commands.fm
HTML File Name: TE%20Commands25.html
Last Updated: 12/19/04 at 14:56:07