Switching Modes
1. Store and Forward Switching
2. Cut-through Switching
3. Fragment-Free Switching
1. Store and Forward Switching
Switch copies each complete frame into the switch memory and do a Cyclic Redundancy Check (CRC) for errors. If an error is found, the frame is dropped and if there is no error, the switch forwards the frame to the destination device. Store and Forward switching can cause delay in switching since Cyclic Redundancy Check (CRC) is calculated for each frame.
2. Cut-through Switching
Switch copies the destination MAC address (first 6 bytes of the frame) of the frame before making a switching decision into its memory. It reduces delay because the switch starts to forward the frame as soon as it reads the destination MAC address and determines the outgoing switch port. Switch may forward bad frames.
3. Fragment-Free Switching
The switches operating in fragment-free switching read at least 64 bytes of the Ethernet frame before switching it to avoid forwarding Ethernet runt frames (Ethernet frames smaller than 64 bytes).