This object controls how a VPLS instance handles frames whose destination MAC address isn't in its forwarding table: true discards such frames, false floods them for processing instead. Admins enable discarding to reduce unnecessary flooding traffic across a large VPLS domain once MAC addresses are expected to be learned. For example, setting vplsDiscardUnknownDest to true on a stable, fully-learned VPLS would drop frames to unrecognized destinations rather than flooding them across all attached pseudo wires.