Requirements and Limitations

The configuration in the following figure has the following requirements and limitations:

• The VPLS nodes with STP redundancy (Switches S1 and S2) must always be the lowest priority STP bridges to ensure that STP port blocking is done by one of the VPLS nodes. For example, the following priorities for the nodes in the following figure will work correctly: S1, priority 8192; S2, priority 4096; R1, priority 32768; and R2, priority 32768.
• For VPLS STP redundancy to work properly, the VPLS nodes must be directly connected to the STP nodes. For example, if a node R3 is added between S2 and R2, node S2 cannot directly detect a failure of the link between R3 and R2.