A known unicast frame is addressed to one destination host whose destination MAC address appears in the receiving switch’s MAC address table. The switch forwards it only through the associated port instead of flooding it. section 6.3.2
PC1 sends to PC2
If PC1 sends a frame to PC2’s MAC address and SW1’s table maps that address to G0/2, SW1 forwards the frame through G0/2. PC2 receives it without other switch ports receiving the frame. By contrast, a missing destination entry creates an unknown unicast frame, which the switch floods. section 6.3.2
Remember these exam distinctions:
- A MAC address table maps MAC addresses to switch ports and supports frame forwarding. section 10.1.1
- An ARP table maps IP addresses to MAC addresses; it does not replace the switch’s MAC address table. section 10.1.1
