Describe cut-through forwarding switching.

What will be an ideal response?

Switches that use cut-through forwarding start sending a frame immediately after reading the destination MAC address into their buffers. The main benefit of cut-through forwarding is a reduction in latency, because the forwarding decision is made almost immediately after the frame is received. For example, the switching decision is made after receiving 14 bytes of a standard Ethernet frame.

The drawback to forwarding the frame immediately is the potential for errors in the frame that the switch would be unable to detect because the switch only reads a small portion of the frame into its buffer. Of course, any errors that occur in the preamble, start frame delimiter (SFD), or destination address fields will not be propagated by the switch, unless they are corrupted in such a way as to appear valid, which is highly unlikely.