I haven't been able to find an obvious way to prevent a port running STP from sending out BPDUs. I'm specifically working with VSTP and the ELS sortware. I can put a port into 'edge' mode, which I presumed would prevent BPDUs from being sent as the port would be connected to a user workstation or something like that. But looking at STP counters BPDUs are being sent, which seems wasteful.