Hi Sri,
A complete ACI L3Out topology would depend on the specific design requirements of your environment, and may vary based on factors such as the number of leaf switches, the number of external routers, and the number of hypervisors.
That being said, here is an example of a basic ACI L3Out topology that includes a hypervisor connected to a leaf switch and an external router connected via an L3Out:
Hypervisor --> vNIC --> Leaf switch --> ACI fabric --> L3Out --> External router
In this topology, the hypervisor would have a vNIC connected to a leaf switch within the ACI fabric. The leaf switch would be connected to the ACI fabric and would have an L3Out configured to route traffic to the external router.
The external router would be connected to the ACI fabric via the L3Out and would have an IP address assigned to its interface.
The L3Out would also have a VLAN assigned to it, and this VLAN would be used to carry traffic between the hypervisor and the external router.
To configure the routing between the hypervisor and the external router, you would need to configure routes on both devices. For example, the hypervisor would need to have a default gateway that points to the IP address of the leaf switch, while the external router would need to have a route to the subnet that the hypervisor is in, with the next hop being the IP address of the L3Out interface in the ACI fabric.
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