How Does the Data Link Layer Prevent Duplicate Frame Delivery in Switched Ethernet?

In the switched Ethernet networks the data link layer uses MAC addressing, switching tables, spanning tree protocols, frame filtering and forwarding and CSMA/CD to prevent duplicate frame delivery.

• In MAC addressing the switches uses the MAC address of the destination present in the frame to send it to desired destination hence, avoiding the duplicate frames.
• In switching table method switches maintains the switching table including the MAC address and port address and when a frame arrives it checks this table if the frame is sent to desired port or not hence, preventing duplicate frame delivery.
• The spanning tree protocol allows only one path to be active between the two nodes that avoids loops that cause duplicate frame delivery. In frame filtering and forwarding the switches checks the MAC address table and then it makes forwarding decision and forwards then forwards the frame.
• In CSMA/CD the frame is transferred when there is no collision in the communication channel and if the collision persists the data transfer is stopped and the system waits for some time to resend the data hence, preventing the duplicate packet delivery.