About Remote Leaf Switches in the ACI Fabric
With an ACI fabric deployed, you can extend ACI services and APIC management to remote datacenters with Cisco ACI leaf switches that have no local spine switch or APIC attached.
The remote leaf switches are added to an existing pod in the fabric. All policies deployed in the main datacenter are deployed in the remote switches, which behave like local leaf switches belonging to the pod. In this topology, all unicast traffic is through VXLAN over Layer 3. Layer 2 Broadcast, Unknown Unicast, and Multicast (BUM) messages are sent using Head End Replication (HER) tunnels without the use of Multicast. All local traffic on the remote site is switched directly between endpoints, whether physical or virtual. Any traffic that requires use of the spine switch proxy is forwarded to the main datacenter.
The APIC system discovers the remote leaf switches when they come up. From that time, they can be managed through APIC, as part of the fabric.
You can configure Remote Leaf in the APIC GUI, either with and without a wizard, or use the REST API or the NX-OS style CLI.