ARP Cache Life Continued
In addition to aging out, devices on the network also replace ARP entries whenever new information is received. For example, if a computer receives a packet from a host that contains a different IP and MAC address than what it has listed in the ARP table, the computer will update its ARP table.
Even though the ARP tables are frequently revised, and their entries have short lives, they reduce network traffic.
Without an ARP table, a device would have to perform an ARP for each packet it wished to send. This would significantly increase network traffic on the local segment.
Increased traffic usually results in increased collisions and network delays.