A unique loopback address is configured on every leaf, spine, and DCI 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. Each border leaf pair connected to DCI switches also shares a VTEP external address. This external address is used with the multi-site DCI feature in Dell Enterprise SONiC.
Autonomous system numbers (ASNs) are configured on all leaf, spine, and DCI switches for use with BGP. Each leaf pair shares an ASN, and all spines in the same site share an ASN. Each DCI switch in this example uses a unique ASN.
The following table lists the loopback addresses and ASNs used in the example switch configuration files:
Switch | Router ID (Loopback 0) | VTEP address (Loopback 1) | VTEP external address (Loopback 2) | ASN |
Leaf 1A | 10.0.2.1/32 | 10.10.10.1/32 | None | 65001 |
Leaf 1B | 10.0.2.2/32 | 10.10.10.1/32 | None | 65001 |
Leaf 2A | 10.0.2.3/32 | 10.10.10.2/32 | 10.10.11.2/32 | 65002 |
Leaf 2B | 10.0.2.4/32 | 10.10.10.2/32 | 10.10.11.2/32 | 65002 |
Leaf 3A | 10.0.2.5/32 | 10.10.10.3/32 | 10.10.11.3/32 | 65003 |
Leaf 3B | 10.0.2.6/32 | 10.10.10.3/32 | 10.10.11.3/32 | 65003 |
Spine 1 | 10.0.1.1/32 | None | None | 65000 |
Spine 2 | 10.0.1.2/32 | None | None | 65000 |
DCI-Site-1 | 10.0.3.1/32 | None | None | 65011 |
DCI-Site-2 | 10.0.3.2/32 | None | None | 65012 |
DCI-Site-3 | 10.0.3.3/32 | None | None | 65013 |