Answer:
to allow for dynamic updates of the network
Step-by-step explanation:
ARP is used to map an IP address to a physical (MAC) address on a local network, and the ARP table is used to store these mappings for quick access.
However, the physical addresses of devices on a network can change over time, for example due to replacement or failure of a device, or when a device moves from one network segment to another. To handle these changes, ARP entries are set to expire after a certain amount of time, typically a few minutes. This forces the device to send a new ARP request to update the mapping if it needs to communicate with the device again, which helps ensure that the ARP table always reflects the current state of the network.
By having ARP entries expire, the ARP table remains accurate and up-to-date, even in environments where devices are frequently added or removed from the network. This helps ensure that IP-to-MAC mappings are always accurate and helps prevent communication errors.