When proxy-ARP/proxy-ND is enabled, the system starts populating the proxy table and responding to ARP-requests/NS messages. To keep the active IP-MAC entries alive and ensure that all the host/routers in the service update their ARP/ND caches, the system may generate the following three types of ARP/ND messages for a specified IP-MAC entry:
Periodic refresh messages (ARP-requests or NS for a specified IP):
These messages are activated by the send-refresh command and their objective is to keep the existing FDB and Proxy-ARP/ND entries alive to minimize EVPN withdrawals and re-advertisements.
Unsolicited refresh messages (unsolicited GARP or NA messages):
These messages are sent by the system when a new entry is learned or updated. Their objective is to update the attached host/router caches.
Confirm messages (unicast ARP-requests or unicast NS messages):
These messages are sent by the system when a new MAC is learned for an existing IP. The objective of the confirm messages is to verify that a specified IP has really moved to a different part of the network and is associated with the new MAC. If the IP has not moved, it forces the owners of the duplicate IP to reply and cause dup-detect to kick in.