A while ago I helped a large enterprise redesign their data center fabric. They did a wonderful job optimizing their infrastructure, so all they really needed were two switches in each location.
Some vendors couldn’t fathom that. One of them proposed to build a “future-proof” (and twice as expensive) leaf-and-spine fabric with two leaves and two spines. On top of that they proposed to use EBGP as the only routing protocol because draft-lapukhov-bgp-routing-large-dc – a clear case of missing the customer needs.
Since then I started wondering whether we’re overselling the benefits of BGP. It’s clearly the right choice if you have a huge fabric, or if you want to run IPv4, IPv6 and EVPN at the same time… but if all you need is IP transport across a half-dozen switches to run VMware NSX on top of that BGP is clearly an overkill.
I tried to summarize my thoughts on whether it makes sense to use BGP in a data center fabric in a short overview document, starting with how would you decide whether it makes sense to use BGP as the only routing protocol in your data center fabric.
Keep in mind that this is just an overview document. You’ll find more details in the leaf-and-spine fabric architectures webinar, and master data center design in building next-generation data center online course.