The following figure shows the autonomous system numbers (ASNs) and router IDs used for the external switches.
The external switches share a common ASN. SmartFabric leafs share a common ASN, and SmartFabric spines share a common ASN.
In this example, ASN 65101 is used on both external switches. By default, all SmartFabric leaf switches use 65011, and all SmartFabric spine switches use 65012.
The IP addresses shown in the figure are loopback addresses used as BGP router IDs on the external network switches. Router IDs on the SFS switches are automatically configured from the SFS default private subnet address block, 172.16.0.0/16.