> if STUN won’t work (some mobile carriers and enterprise networks) then port-mapping protocols probably won’t work either
This is a bad conclusion. STUN dies on endpoint dependent mappings and proper port mapping setups are specifically to allow this. The oversubscription enabled by endpoint dependent mapping is drastically higher if you have the memory to run it. The correlation between modes and support for the protocols does not work in the way you think.
Apologies for the confusion. I did not know about this type of setup. I am aware of the oversubscription problem but didn’t know it was being mitigated in any way.
Do you have examples on environments that use PMPs in such a way? And if so, which PMPs? (I’m asking because if I can avoid UPnP and use the other more sane protocols, it’d still be a win)
This is a bad conclusion. STUN dies on endpoint dependent mappings and proper port mapping setups are specifically to allow this. The oversubscription enabled by endpoint dependent mapping is drastically higher if you have the memory to run it. The correlation between modes and support for the protocols does not work in the way you think.