Address Resolution Protocol (ARP) is a layer 2 protocol that maps the device MAC addresses to their IP addresses. A gratuitous ARP is an ARP response that is not prompted by an ARP request. A node sends a gratuitous ARP message as a broadcast to announce or update its IP to MAC mapping to the entire network.

You can use one of the following to configure the parameters and enable the gratuitous ARP:

• The web interface
• 46xxsettings.txt file
• Avaya Aura® Device Services (AADS)
• DHCP server

The phone administrators can enable the gratuitous ARP feature to update an existing ARP cache with a MAC address received in a gratuitous (unsolicited) ARP message. The phones accept incoming gratuitous ARP messages if the message meets the following conditions:

• IP Address is available in the ARP Table.
• The source hardware address is a Unicast address.
• The packet destination address is a Broadcast address.