utilize tunneling after all. In particular, for 3GPP accesses tunneling does not seem to be the right way to go, due to reasons described in depth in Section 5.2.2. That said, network-based tunneling solutions do seem to be playing an important role: the tunneling Deploying IPv6 in 3GPP Networks over single address family infrastructures can be performed, for example by the Consumer Premises Equipment (CPE) or by an access concentrator (such as Packet Data Network Gateway - PGW). For more or less the same reasons there were for developing tunneling-based transition tools, protocol translation based tools have also been developed. The toolset for translation is much smaller, and essentially is about IPv4/IPv6 Network Address Translation (NAT64) (described in Section 5.3.3). The protocol translation between incompatible IPv4 and IPv6 causes issues described in Section 5.2.1, and hence has been disfavored by many. However, if the issues are accepted or worked around, the translation can be a powerful tool. And because of that, the IETF is currently spending a significant number of cycles in perfecting the protocol translation technologies (or to put it another way, to mitigate and minimize the issues). 5.1.1 Phasing the Transition The original idea of dual-stack transition has been watered down by the industry not actively deploying IPv6 early enough to avoid the need for more complex tools - not an uncommon problem for any resource exhausting situation that mankind faces. Now, as the limited resource of IPv4 addresses is really in short supply, work to deploy IPv6 has begun. In part to solve the chicken and egg problem, several major content providers have gone to the trouble of making their content available in IPv6. These deployments got publicity due to events such as World IPv6 Day on 8th June in 2011, see http://www.worldipv6day.org, and World IPv6 Launch on 6th June in 2012, see http://www.worldipv6launch.org. Following these significant deploy- ments, it is now possible for network operators to actually get 