ARP Stands for Address resolution protocol. Which is used to get mac address. Now question is that how ARP get the mac Address. We can understand the terminology by below diagram.

to understand the ARP Terminology ping packet comes in picture, lets brief discussion about ping. Ping works on ICMP Protocol and port no. is 1.

Ping stands for packet internet groper. It is used to check and verify the reachability of any host in the IP network.

Lets understand the ARP. when PC A wants to ping PC-B. pc-a will check the ARP table if there is no entry of ARP Table then pc-a will hold the ping packet and send the ARP packet to PC-B. PC-B receive the ARP packet and share his mac address to PC-A through ARP Reply. Once PC-A Receive the mac address then PC-A sends the ICMP Echo packet as a ping to PC-B and finally PC-B will send ICMP Echo reply to Pc-A.

This is how ARP gets the mac address.