MPLS TE setup and hold priority

MPLS-TE tunnel priorities are used so tunnels can preempt other tunnels. There are 8 priority levels (0-7) for both setup and holding priorities, with 0 being the most preferred and 7 the least preferred (default). It's common to set the same value for both priorities. More preferred tunnels preempt less preferred tunnels.

Setup priority defines preference for preempting less preferred tunnels, while holding priority defines how important the tunnel is once established. To avoid a tunnel from being preempted once established, configure setup priority 7 and holding priority 0.

Higher bandwidth tunnels should have more preferred setup and hold priorities. Most CLIs don't allow configuration of a holding priority more preferred than the setup priority to prevent loops between tunnels preempting each other repeatedly.

Use show mpls traffic-eng tunnels tunnel to check the current priority of a tunnel. Configure priority setup and holding priority in interface configuration mode with the command tunnel mpls traffic-eng priority.

This is how you can check the tunnel priorities:

PE1#show mpls traffic-eng tunnels tunnel 1 | include Priority

    Bandwidth: 750      kbps (Global)  Priority: 7  7   Affinity: 0x0/0xFFFF

This is how you can configure the setup and hold priority:

PE1(config)# interface Tunnel1
PE1(config-if)# tunnel mpls traffic-eng priority 6 5

The first value is the setup priority. The second value is the hold priority.