VPLS networks are typically used to interconnect different customer sites using different access technologies such as Ethernet and bridged-encapsulated ATM PVCs. Typically, different Layer 2 devices can support different types of STP and even if they are from the same vendor. In some cases, it is necessary to provide BPDU translation to provide an inter-operable e2e solution.
To address these network designs, BPDU format translation is supported on 7210 SAS devices. If enabled on a specific SAP or spoke-SDP, the system will intercept all BPDUs destined to that interface and perform required format translation such as STP-to-PVST or vice versa.
Similarly, BPDU interception and redirection to the CPM is performed only at ingress meaning that as soon as at least 1 port within a specific VPLS service has BPDU translation enabled, all BPDUs received on any of the VPLS ports will be redirected to the CPM.
BPDU translation involves all encapsulation actions that the datapath would perform for a specific outgoing port (such as adding VLAN tags depending on the outer SAP and the SDP encapsulation type) and adding or removing all the required VLAN information in a BPDU payload.
This feature can be enabled on a SAP/spoke only if STP is disabled in the context of the specific VPLS service.