I feel like it depends a lot on the scale/target usage (public vs private cloud).

But at $dayjob, we are leveraging 
We like the simplicity of vxlan with minimal overlay configuration. There are some scaling/performance issues with stuff like l2 population.

VLANs are okay but it's hard to predict the next 5 years of growth.

On Mon, May 10, 2021 at 8:34 AM Arnaud Morin <arnaud.morin@gmail.com> wrote:
Hey large-scalers,

We had a discusion in my company (OVH) about neutron drivers.
We are using a custom driver based on BGP for public networking, and
another custom driver for private networking (based on vlan).

Benefits from this are obvious:
- we maintain the code
- we do what we want, not more, not less
- it fits perfectly to the network layer our company is using
- we have full control of the networking stack

But it also have some downsides:
- we have to maintain the code... (rebasing, etc.)
- we introduce bugs that are not upstream (more code, more bugs)
- a change in code is taking longer, we have few people working on this
  (compared to a community based)
- this is not upstream (so not opensource)
- we are not sharing (bad)

So, we were wondering which drivers are used upstream in large scale
environment (not sure a vlan driver can be used with more than 500
hypervisors / I dont know about vxlan or any other solution).

Is there anyone willing to share this info?

Thanks in advance!