Damien Miller writes:

> Sure, it's supported but does any network infrastructure enable it
> by default? AFAIK ECN is only a cost if nothing on-path is actually
> doint congestion marking.

I don't know who defaults to on, because we always enable it by
force on all of our gear.  In the last 10 years I have had no issue
with that on Open, Free, Linux, or Fortinet or Juniper switches.

The time to default this to on across the board was likely a
decade ago.

--lyndon