Is it possible to Overlap the IPs within same VRF for Different EPG/BD?

[Mahmoud Nossair]

Hi,

I have an ACI fabric working in Layer 2 mode only (ACI is NOT a Gateway), each EPG represented as a customer , so Is it possible to Overlap the IPs within same VRF for Different EPG/BD?

(No need for EPGs to communicate with each others as each EPG is a customer).

The Upstream device (Nexus 7710) will be a VRF aware so each EPG/VLAN will be in different VRF to retain the traffic segregation to rest of the network.

and if possible what is the Impact?

My per my understanding the ACI fabric can't have a Different MACs for the same IPs even if they in different EPGs/BD 

[Manuel Velasco · Accepted solution]

Hi Mahmoud,

Assuming that your ACI Fabric is going to act as a layer 2 fabric only for this VRF.  Having overlapping IPs would be possible as long as you disable “unicast routing” under the BD.  When unicast routing is disable under the BD, ACI will only learn MAC Endpoint and not IPs.

Note that if you put all of the EPGs in a single BD, any time there is a broadscast from any EPG/vlan in this BD, it will be forward to all endpoints in the BD.  In ACI the BD represent the forwarding domain.  

[Mahmoud Nossair]

Many Thanks Manuel,