Enabling Soft-Preemption Over Frr Backup Tunnels - Cisco CRS Configuration Manual

Implementing MPLS Traffic Engineering
DETAILED STEPS
Command or Action
Step 1
configure
Example:
RP/0/RP0/CPU0:router# configure
Step 2 mpls traffic-eng
Example:
RP/0/RP0/CPU0:router(config)# mpls traffic-eng
Step 3 attribute-set path-option attribute-set-name
Example:
RP/0/RP0/CPU0:router(config-mpls-te)#
attribute-set path-option PO3AttrSet
Step 4 path-selection cost-limit 3
Example:
RP/0/RP0/CPU0:router(config-te-attribute-set)#
path-selection cost-limit 3

Enabling Soft-preemption over FRR Backup Tunnels

Perform these tasks to enable LSP traffic to be moved over the backup tunnel when the LSP is soft-preempted.
With this configuration, when there is a soft-preemption, the MPLS TE process triggers a rewrite to move
the traffic on the backup tunnel, if the backup tunnel is ready. The rest of the soft-preemption process remains
unchanged.
Before You Begin
Ensure that the following configurations are enabled before enabling soft-preemption over FRR backup:
• Soft-preemption enabled.
• Fast-reroute (FRR) backup tunnel is activated.
SUMMARY STEPS
1. configure
2. mpls traffic-eng
3. soft-preemption frr-rewrite
4. Use the commit or end command.
Purpose
Enters global configuration mode.
Enters MPLS-TE configuration mode.
Enters attribute-set path option configuration mode.
The configuration at the attribute-set path-option
Note
level takes precedence over the values configured
at global and interface tunnel level.
Sets the upper limit on the path aggregate admin-weight
when computing paths for MPLS TE LSPs per path-option
attribute set.
Cisco IOS XR MPLS Configuration Guide for the Cisco CRS Router, Release 5.1.x
Enabling Soft-preemption over FRR Backup Tunnels
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