Unfortunatelly we are finally switching away from RTMFP, because of abundance of symetric NATs. In Netherlands telecommunication company KPN is giving their customers symmetric NAT devices and because KPN is ubiquitous, RTMFP is not a suitable solution for video communication here. KPN help desk assures that they will keep issuing devices with symmetric NAT, because most applications can be made to work by whether enabling uPnp or by setting up the port forwarding, thus they do not admit that their devices are defective.
So this is the question for future. Is Adobe planing to add uPnp feature to RTMFP, or even better - give us, developers, the possibility to set the port range RTMFP connection must use?
at this time there are no plans to add uPnP to RTMFP.
uPnP is not needed for correct RTMFP behavior when NATs follow RFC 4787 (BCP 127), particularly requirements REQ-1, REQ-3, and REQ-11. RTMFP can operate in some circumstances where Internet Best Current Practices are not followed, but not in all circumstances.
i'm personally hopeful that the mass adoption of IPv6 will reduce the amount of symmetric NAT in the Internet and improve the performance of all P2P protocols, including RTMFP. RTMFP works perfectly over IPv6; however, the Cirrus cluster at this time has no IPv6 connectivity from our network provider, so IPv6 NAT and firewall traversal services are unavailable, and service for IPv6-only hosts is unavailable.
A lot more people would use your system if you would.