Command
Spanning-Tree Uplinkfast
Use
This command allows the switch to quickly select another root port if it detects a failure. The new root port moves from blocking to forwarding in under 5 seconds.
Syntax
Switch(config)#spanning-tree uplinkfast
Example
In the below example we will configure SW2 to use uplinkfast. After that, we will disable the links to its root switch SW1. First, we configure uplinkfast globally.
SW2(config)#spanning uplinkfast |
Looking at spanning tree, we see that Fa0/23 is currently the root port.
SW2(config-if-range)#do show spanning vlan 10 VLAN0010 Bridge ID Priority 16394 (priority 16384 sys-id-ext 10) Interface Role Sts Cost Prio.Nbr Type |
After disabling both ports to SW1, spanning-tree makes Fa0/21 root and moves the port to forwarding.
SW2(config)#int ra fa0/23-24 VLAN0010 Bridge ID Priority 16394 (priority 16384 sys-id-ext 10) Interface Role Sts Cost Prio.Nbr Type |
SW2(config-if-range)#do show spanning vlan 10 VLAN0010 Bridge ID Priority 16394 (priority 16384 sys-id-ext 10) Interface Role Sts Cost Prio.Nbr Type |