The stp vpls-subinterface enable command enables an interface to instruct its VSI-bound sub-interfaces to update ARP and MAC entries after it receives TC BPDUs.
The undo stp vpls-subinterface enable command disables an interface from instructing its VSI-bound sub-interfaces to update ARP and MAC entries after it receives TC BPDUs.
By default, an interface does not instruct its VSI-bound sub-interfaces to update ARP and MAC entries after it receives TC BPDUs.
Usage Scenario
In normal situations, when an STP topology changes and an interface receives TC BPDUs, the interface recalculates the spanning tree, and accordingly all devices will update ARP and MAC entries. However, if an STP-enabled interface has sub-interfaces that are bound to VSIs, the sub-interfaces cannot detect the topology change immediately, and ARP and MAC entries cannot be updated on the VPLS network in time. To prevent this problem, run the stp vpls-subinterface enable command to enable an STP-enabled interface to instruct its VSI-bound sub-interfaces to update ARP and MAC entries after it receives TC BPDUs.
Prerequisites
To set the stp vpls-subinterface enable command, run the stp enable command on the interface to enable STP.
Configuration Impact
When the forwarding status of an interface goes to Discarding, its VSI-bound sub-interfaces will go to the Flowdown state to prevent loops on the VPLS network on which a CE is dual-homed to PEs.