This Recommendation describes packages to enable various network address translator (NAT) traversal techniques to be employed in order to facilitate media flow between networks. The media gateway controller (MGC) may utilize any of the packages in any order to gather addresses, map them and then maintain connectivity with and through NATs.
ITU-T H.248.50-2010 history
2016ITU-T H.248.50-2016 Gateway control protocol: NAT traversal toolkit packages (Study Group 16)
2010ITU-T H.248.50-2010 Gateway control protocol: NAT traversal toolkit packages (Study Group 16)