Which term makes traffic switching decisions based on the MAC address of the sending and receiving devices through transparent bridging?

• A. Switch
• B. MAC Flood
• C. Port Security
• D. Persistent MAC Learning

Answer: (A)

Switching decisions at the data link layer are driven by MAC addresses learned through transparent bridging. A switch listens to frames on each port and builds a MAC address table that maps every observed source MAC to the port it came from. When a frame arrives, the switch uses the destination MAC to decide which port to forward it to; if the destination is known, it sends directly to that port, and if not, it floods to all ports except the source. This automatic learning and forwarding based on MACs is the hallmark of a switch operating in a transparent bridge environment. The other concepts describe different ideas: MAC flood refers to overwhelming the switch’s MAC table, Port Security restricts which MACs can be learned on a port, and Persistent MAC Learning is about retaining learned MAC entries—none of these define the basic switching behavior.