tate. This might lead to an excessive amount of log information being produced, since each translation binding may need to be logged due to local governmental regulation. Does the transition/migration solution have address or port number sharing ratio con- cerns? This is topical in deployments where public IPv4 addresses still have to be used. Since the days of NAT44 port sharing the technology and deployment require- ments have also expanded into sharing one address across multiple end devices. The A+P or address and port sharing [20] is here to stay and driven by recent transi- tion technologies like Mapping of Address and Port with Encapsulation or Translation (MAP) [21]. Transition Toolbox From the plethora of IPv6 transition tools that the IETF has produced, we have included the ones that are the most relevant for 3GPP networks. This does not mean that the other tools could not be used. They can be vendor or network specific choices, but are not part Deploying IPv6 in 3GPP Networks Enter IPv6-only cellular connection Dual-stack UE side transition bearer tools Deploy bearers Tunneling Deploy v4+v6 NAT64 in allowed acceptable in network network No and select Stateless No and select IPv6 Deploy Deploy Deploy Stateless v4 in 464XLAT MAP-T network (simple) Legend: Dual-stack for applications. Provisioning IP mobility Deploy MAP-E required for UEs beyond DNS IPv4-only for applications Deploy Deploy IPv6-only for application DS-Lite DSMIPv6 B4 in UE (complex) Dual-stack for applications Figure 5.1 Transition technology solution selection flowchart when deploying IPv6-enabled PDN Connectivity that also provides access to IPv4 PDNs. of the big picture of IPv6 transition in 3GPP access. Furthermore, it is good to realize that as the UEs can also access non-3GPP access networks, they may find it useful to implement some tunneling based transition solutions for such networks (if they wish to obtain IPv6 connectivity). Figure 5.1 shows a flowchart that aims to recommend a transition tool to use when certain requirements 