Configure RSVP Soft Preemption

Non-adaptive and/or FRR enabled LSPs cannot be configured with soft preemption capability. In this scenario, the LSP must be disabled first to configure soft preemption based on the policies, other changes also may be required, such as removing FRR.

All secondary paths configured on the LSP would be allowed to have soft preemption configured independently.

The following steps must be followed to configure soft preemption.

  1. Configure the device.
    device# configure
  2. Enable the MPLS router.
    device(config)# router mpls
  3. Define the path.
    device(config-router-mpls)# path sec
    This defines the path with the name of "sec".
  4. Configure the LSP
    device(config-router-mpls-path-sec)# lsp test
    This defines the LSP with a name of "test".
  5. Set the egress router of the LSP.
    device(config-router-mpls-lsp-test)# to 10.1.1.100
    This designates the egress router IP address of 10.1.1.100.
  6. Configures the LSP as adaptive.
    device(config-rouoter-mpls-lsp-test)# adaptive
    This enables the LSP to be dynamically modified.
  7. Set the LSP to have preemption capability.
    device(config-router-mpls-lsp-test)# soft-preemption
    This sets the primary path.
  8. Configure the secondary path.
    device(config-router-mpls-lsp-test)# secondary-path sec
  9. When FRR is configured, remove the FRR configuration.
    device(config-router-mpls-lsp-test)# traffic-eng mean-rate 100
  10. Configure the secondary path to be adaptive.
    device(config-router-mpls-lsp-test-secpath-sec)# adaptive
  11. For each secondary path, where soft preemption is intended to be configured, mark them adaptive, when already not adaptive, configure SOFT preemption.
    device(config-router-mpls-lsp-test-secpath-sec)# soft-preemption
    This sets the secondary path.
  12. Enable the LSP.
    device(config-router-mpls-lsp-test-secpath-sec)# enable
    Connecting signaled LSP test

The soft-preemption command enables soft preemption functionality. This command must be used on both, the primary and secondary paths.

device# configure 
device(config)# router mpls
device(config-router-mpls)# path sec
device(config-router-mpls-path-sec)# lsp test
device(config-router-mpls-lsp-test)# to 10.1.1.100
device(config-router-mpls-lsp-test)# traffic-eng mean-rate 100
device(config-router-mpls-lsp-test)# adaptive
device(config-router-mpls-lsp-test)# soft-preemption
device(config-router-mpls-lsp-test)# secondary-path sec
device(config-router-mpls-lsp-test)# traffic-eng mean-rate 100
device(config-router-mpls-lsp-test-secpath-sec)# adaptive
device(config-router-mpls-lsp-test-secpath-sec)# soft-preemption
device(config-router-mpls-lsp-test-secpath-sec)# enable