Assuming that MMRP is used in a specific B-VPLS, under failure conditions the time it takes for the B-VPLS forwarding to resume may depend on the data plane and control plane convergence plus the time it takes for MMRP exchanges to settle down the flooding trees on a per ISID basis.
To minimize the convergence time, the Nokia PBB implementation offers the selection of a mode where B-VPLS forwarding reverts for a short time to flooding so that MMRP has enough time to converge. This mode can be selected through configuration using the configure service vpls b-vpls mrp flood-time value command where value represents the amount of time in seconds that flooding is enabled.
If this behavior is selected, the forwarding plane reverts to B-VPLS flooding for a configurable time period, for example, for a few seconds, then it reverts back to the MFIB entries installed by MMRP.
The following B-VPLS events initiate the switch from per I-VPLS (MMRP) MFIB entries to ‟B-VPLS flooding”:
Reception or local triggering of a TCN
B-SAP failure
Failure of a B-SDP binding
Pseudowire activation in a primary/standby HVPLS resiliency solution
SF/CPM switchover because of the STP reconvergence