1. A ping request is sent from computer A to computer H. This triggers an ARP request from A to its default gateway to resolve the MAC address for H's IP address. 2. The ARP request propagates through the network, triggering ARP replies that allow the switch and router ARP tables to be populated with the correct MAC-IP mappings to route the ping request. 3. Once all the ARP tables are populated, the actual ping request packet is finally able to travel the network path from A to H.