BD Static Mac Address configuration

[Fernando Hernández]

Hey guys.
Do you know if possible to configure a static mac address on BD?
We are migrating default gateways from Switches Core (N7K) to ACI and would like to keep same mac addresss of each SVI on the BD so the servers wont have an arp impact.
My question is cause I have seen all BD have the same MAC adress, so im not sure if its a good idea to change it, and also if that mac address configuration is used for arp.

Regards!

[Robert Burns · Accepted solution]

Yes you can use a static MAC on the SVI of a BD.  This is commonly used during the migration of a default GW from legacy to ACI to minimize any disruption to endpoints (no need to re-arp for new GW address).  Just ensure you shut down the SVI on the legacy side when you enable it on ACI BD.  A word of caution is just ensure you don't re-enable the legacy SVI, which would introduce a MAC flap/conflict in the network.  Migrate once, then remove the legacy SVI - just be careful it never gets "restored" from a backup config.

As for the second question, yes all ACI BDs used the same default L2 MAC for SVIs. Since it's just L2 and should never cause any issues.  No issues if some BDs have custom MACs, while others use the default.

Robert

[Fernando Hernández]

Nice.
Thank you so much for your answer. Really helpful