Configuring Tunnel Re-optimization

Tunnel re-optimization is configured to allow a device to dynamically adjust paths for tunnels.

Usage Scenario

Topology and link attributes of an IP/MPLS network are changeable. As a result, a path over which an MPLS TE tunnel has been established may not be optimal. Tunnel re-optimization can be configured to allow the MPLS TE tunnel to be reestablished over an optimal path.

Re-optimization is implemented in either of the following modes:

Periodic re-optimization: The system attempts to reestablish tunnels over better paths (if there are) at a specified interval. This implementation prevents manual intervention and reduces configuration workload.
Manual re-optimization: A user configures the system to attempt to reestablish TE tunnels over better paths if there are.

Tunnel re-optimization is performed based on tunnel path constraints. During path re-optimization, path constraints, such as explicit path constraints and bandwidth constraints, are also considered.

Tunnel re-optimization cannot be used on tunnels for which a system selects paths in most-fill tie-breaking mode.

Pre-configuration Tasks

Before configuring tunnel re-optimization, configure an RSVP-TE tunnel.

Procedure

Configure periodic re-optimization.
1. Run system-view
  The system view is displayed.
2. Run interface tunnel interface-number
  The tunnel interface view of the MPLS TE tunnel to be established is displayed.
3. Run mpls te reoptimization [ frequency interval ]
  Periodic re-optimization is enabled.
4. (Optional) Run mpls te inter-area reoptimization
  Inter-IGP-area RSVP-TE P2P tunnel re-optimization is enabled. In an inter-IGP-area scenario, if re-optimization is triggered on the ingress, a better path in the area where the ingress resides can only be detected, but a better path exists in the downstream area cannot be detected. If the latter exists only, re-optimization cannot be performed to reestablish the RSVP-TE P2P LSP over the better path. Perform this step to enable inter-IGP-area RSVP-TE P2P tunnel re-optimization. After this command is run, the RSVP-TE P2P LSP is reestablished over the better path in the downstream area.
5. (Optional) Run quit
  Return to the system view.
6. (Optional) Run mpls
  The MPLS view is displayed.
7. (Optional) Run mpls te reoptimization link-up disable
  Link change-triggered RSVP-TE tunnel re-optimization is disabled.
  
  If route flapping occurs on a network, tunnel re-optimization is repeatedly triggered, which wastes network resources. To prevent the problem, disable link change-triggered RSVP-TE tunnel re-optimization. After this command is run, tunnels are not optimized.
  
  This command prevents tunnel re-optimization triggered by link changes. If the frequency interval parameter is set in the mpls te reoptimization command run in the tunnel interface view to enable tunnel re-optimization for a specific tunnel, the tunnel can be optimized properly.
  
  The mpls te reoptimization link-up disable command disables all tunnel re-optimization functions.
8. Run commit
  The configuration is committed.
Configure manual re-optimization:
Configure manual re-optimization. Run the following command in the user view mpls te reoptimization [ auto-tunnel name tunnel-interface | tunnel tunnel-number ]

Manual re-optimization is configured.

Manual re-optimization can be enabled on a specific or all tunnels on a node.

Verifying the Configuration

After completing the configuration, run the display mpls te tunnel-interface command on the ingress of the tunnel to view the following information:

Whether periodic re-optimization is enabled
Interval between periodic re-optimization processes