STP PortFast

PortFast - A switch places a port in the forwarding state immediately when physically active. No other STP devices should be connected, therefore its most appropriate for end-user devices. With no PortFast, ports must wait maxage plus twice forwading delay (default 50 seconds). PortFast bypasses listening and learning states.
Because PortFast should only be connected to end-station devices, PortFast BPDU guard can be used to prevent BPDU's seen on the portfast port by putting the port into an ErrDisable state. ErrDisable will disable the port and prevents BPDU from being received, the admin must manually put port back into service.