Enable/Disable trusted port on the specified port. Trusted ports are uplink ports connected to PPPoE servers. If a PADO (PPPoE Active Discovery Offer), PADS (PPPoE Active Discovery Session-confirmation), or PADT (PPPoE Active Discovery Terminate) packet is sent from a PPPoE server and received on a trusted port, the Switch forwards it to all other ports. If a PADI or PADR packet is sent from a PPPoE client but received on a trusted port, the Switch forwards it to other trusted port(s). Untrusted ports are downlink ports connected to subscribers. If a PADI, PADR, or PADT packet is sent from a PPPoE client and received on an untrusted port, the Switch adds a vendor-specific tag to the packet and then forwards it to the trusted port(s). The Switch discards PADO and PADS packets which are sent from a PPPoE server but received on an untrusted port.