Cisco Nexus 7000 Series Configuration Manual page 59

Configuring VXLAN BGP EVPN
ARP Suppression
into the network (VXLAN-encapsulate it toward the IP core since original requestor was remote) so that it
will reach the original requestor.
Figure 12: ARP Suppression
Unknown unicast (packet) suppression
Typically, an unknown unicast scenario arises when an end host has resolved the ARP but the MAC address
of the end host is not available/updated in the switch.
Unknown unicast traffic from an end host is by default flooded in the VLAN. It is possible to avoid the flooding
of this traffic to the overlay network without affecting the flooding of this traffic on local host/sever ports
attached to the ToR switch. Use the suppress-unknown-unicast command to do the same.
The suppress unknown unicast function is supported on ToRs/VTEPs in a VXLAN EVPN fabric. This function
allows flooding of traffic within the attached switch by including local host/server ports attached to the ToR
switch in the output interface index flood list (OIFL) and excluding overlay Layer-3 ports in the hardware.
Cisco Nexus 7000 Series NX-OS VXLAN Configuration Guide
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