Endpoint between leaf switches. Both IP/MAC addresses will be shared ?

[palani2010]

Scenerio 1

If the gateway is configured on BD, will both the MAC and IP addresses be shared between the leaf switches?

Scenerio 2

If the gateway is configured on the firewall using L3 out, will both MAC addresses be shared between leaf switches?

[RedNectar]

Hi @palani2010 ,

Firstly, you need to understand the dynamic nature of ACI.

So in Scenario 1, when you configure a gateway IP in a BD, NO SWITCHES LEARN THE MAC OR IP.

However, the moment that a static mapping (or dynamic mapping if using the Virtual Machine Manager) is made in an EPG to an interface or VPC, the gateway IPs (and MAC address) that serve that EPG (via its link to a BD) will be dynamically pushed to the switch that owns the port, (or switches, in the case of a VPC).

Add more static mapping to more leaves, the same IP and MAC addresses are learned by more switches. It's as simple as that.  No other switch needs to learn these gateway IPs or MAC addresses.

In Scenario 2, if a gateway is configured on a firewall then you don't want to be using a L3Out - not if the gateway IP is meant to be a default gateway for devices.

When a L3Out is configured, you are configuring a very stock standard IP subnet between two routers - typically a point-to point link where the MAC addresses of each end are learned by the other end via ARP, and the IP address of the neighbour is learned via whatever routing protocol is deployed.