Short version: In general, what's the best way to advertise an anycast address to ACI from multiple independent/geo-redundant platforms? For multi-pod ACI, is the only option to stretch a single L3Out across all pods and systems, since the anycast ad...
For those wondering, we ended up with "solution 2" in the original post: peering with two central border leafs we consider more critical than all the normal ToR-leafs, for each pod.
