Read the MAC address table
Three PCs share one LAN across two switches. Generate some traffic, then use the switches' MAC address tables to answer the questions. Run show mac address-table on SW1 after the pings so you can see what it learned.
How it works: this is VulnTech NetLab, a network simulator running in your browser. Click a device in the diagram to open its console and type commands, just like on real equipment (? shows help, Tab finishes a word). Click a cable to inspect it. Tasks tick themselves off as you complete them; questions are answered in the box under each task. Your work is kept if you reload; Reset starts the network over.
Solution explanation
The ping made PC1 ARP for PC3: the broadcast request was flooded everywhere, and PC3's reply came back through SW2 into SW1's Gi0/1. So SW1 learned PC3's MAC 001a.dd6c.939f on Gi0/1, the port that leads towards it, even though PC3 is plugged into SW2. Frames for unknown unicast addresses are flooded out every port in the VLAN except the one they arrived on.
Show solution
[PC1]
ping 10.1.1.13
ping 10.1.1.1
[SW1]
enable
show mac address-table
[PC3]
ifconfig en0