Back-pressure allows a port to force a collision when there are no buffers to receive frames. Because collision is only meaningful on a port operating in half-duplex, back-pressure enhancement does not apply to full-duplex ports. When set to enabled(1), buffer starvation causes the switch to force collisions when receiving frames on (half-duplex) ports. This, in turn, signals network nodes that are connected to these ports to retransmit their frames. It is expected that this transit delay enables the switch to free up buffers to successfully receive the frames. When set to disabled(2), the switch does not apply back- pressure when there is buffer starvation. The default value is disabled(2).