Continuing to experiment with All-Things-Networky using Cisco’s Packet Tracer. Here’s the network:

Here’s the addressing table. Two routers, two laptops attached to the wireless access point, and three PC clients- IPv4 addresses, MAC addresses are as follows:

First, I used the CLI/terminal on client 172.16.31.2 to ping the client at 172.16.31.3, first clearing the ARP cache by using arp -d :

In this example, the client 172.16.31.2 does not know the MAC address of client 172.16.31.3, so an ARP request is sent (we can see the 8-bit, ‘F’ octets reflecting this), and received by the client:

Here’s the PDU

Note the the receiving client looks at the ARP packet, sees that it’s IP address matches what is being asked for, and sends a reply ARP with its MAC address