__ I'm very immature __ I'm appropriately mature for my age __ I'm very mature __ I'm gaining maturity (growing personally) __ I have most or all the requisites for personal growth __ people who know me would agree with my answers above.
So the frame gets broadcasted throughout the broadcast domain, until the end device with a matching MAC address responds to the broadcast, thus giving the switch a new source address to add to its MAC table. It duplicates the frame to all Ethernetports, except the port it came from.
I'm guessing you're referring to a switch more rather than something that forks an Ethernet cable. Forking the cable would cause all kinds of issues in terms of Mac and logical addresses. As for switches, they work by building a forwarding table as they receive packets.