DHCP relay redundancy

When the two VSX switches are configured for DHCP relay on their VLAN interfaces, only the primary switch actively relays DHCP client requests to the server. The secondary switch acts as a backup. If the primary VSX switch goes down, the secondary switch takes over. Even though both rimary and secondary switches receive the DHCP request, the primary switch takes precedence.

Both devices do not end up relaying DHCP requests to the server as duplicates. That scenario is usually the case with typical aggregation switches running VRRP-based redundancy.