vxlan arp suppression on nx-os

[sachin30720041]

Hello All,

I am trying to understand suppress-arp under 'member vni 1000'.

According to my understanding, If the mac address of the remote end host is present on the local VTEP then the local VTEP responds back with the mac address of the remote host. And hence suppresses the arp request in the VXLAN network.

interface nve1
member vni 10000
suppress-arp
ingress-replication protocol bgp

But above mentioned behavior stays the same even if 'suppress-arp' is present under 'member vni 10000' or not. then what is the purpose of suppress-arp under 'member vni 10000'.

Thanks,

Sachin

[Pedroxh]

Hi

ARP suppression is a feature that reduces the flooding of ARP request broadcasts upon the network. ARP suppression is enabled on a per VNI basis. Once enabled, VTEPs maintain an ARP suppression cache table for known IP hosts and their associated MAC addresses in the VNI segment.

At the point an end-host sends an ARP request, the local VTEP intercepts the ARP request and checks its ARP suppression cache for the IP. At this point, one of 2 things will happen:

• Hit - If there is a match within the cache - the local VTEP sends an ARP response on behalf of the remote end host.
• Miss - If the local VTEP doesn't have the ARP-resolved IP address in its ARP suppression table, it floods the ARP request to the other VTEPs in the VNI.

Check this link below

https://www.packetcoders.io/how-to-build-a-nxos-9000v-based-evpn-vxlan-fabric/

[MHM Cisco World]

local VTEP will receive the Mac-IP from other VTEP and store it and then when any host connect to local VTEP ask Mac address it send arp instead of VTEP flood ARP it use the table Mac-IP and reply to host connect to it. 
this suppress the ARP. 

[rwu]

Hi, I actually have the same question which is actually not answered. What sachin30720041 asked is why we need the command "suppress-arp"? Without the command, the VTEP works the same way. If the ARP table of local VTEP has the MAC/IP entry of the remote host, it'll reply to local host immediately which suppresses ARP request flooding right? If so, why do we need that command? It seems to me a redundant command. This is the real question. Could you please clarify it? Thanks.