A unique loopback address is configured on every leaf and spine switch in the topology for use as a BGP router ID. A second loopback address is configured on every leaf switch for use as the VTEP address. Each leaf pair shares the same VTEP IP address. If a DCHP server is used for NSX host overlay network TEP addresses, each leaf switch has a third loopback address that is used as the DHCP relay source.
Autonomous system numbers (ASNs) are configured on all leaf and spine switches for use with BGP. Each leaf pair shares an ASN, and all spines share an ASN.
The table below lists the loopback addresses and ASNs used in the example switch configuration files.
Switch | Router ID (Loopback 0) | VTEP address (Loopback 1) | DCHP relay source address (Loopback 2) | ASN |
Leaf 1A | 10.0.2.1/32 | 10.10.10.1/32 | 10.1.1.1/32 | 65101 |
Leaf 1B | 10.0.2.2/32 | 10.10.10.1/32 | 10.1.1.2/32 | 65101 |
Leaf 2A | 10.0.2.3/32 | 10.10.10.2/32 | 10.1.1.3/32 | 65102 |
Leaf 2B | 10.0.2.4/32 | 10.10.10.2/32 | 10.1.1.4/32 | 65102 |
Spine 1 | 10.0.1.1/32 | None | None | 65100 |
Spine 2 | 10.0.1.2/32 | None | None | 65100 |