Cut-Through (Real Time)

Cut-Through (Real Time)
With the cut-through switching method, the LAN switch copies only the destination address
(the first six bytes following the preamble) onto its onboard buffers. It then looks up the hardware
destination address in the MAC switching table, determines the outgoing interface, and
forwards the frame toward its destination. A cut-through switch provides reduced latency
because it begins to forward the frame as soon as it reads the destination address and determines
the outgoing interface.
Some switches can be configured to perform cut-through switching on a per-port basis until
a user-defined error threshold is reached. At that point, they automatically change over to storeand-
forward mode so they will stop forwarding the errors. When the error rate on the port falls
below the threshold, the port automatically changes back to cut-through mode.