CLAT in UE and PLAT in network Not supported (requires BIH) - (BIH in UE) IPv6-only connection from the UE. The Client Side Translator (CLAT) is, in the 3GPP case, located within the UE and does a stateless algorithmic translation from a private RFC 1918 IPv4 address to a global IPv6 address. The beauty of the 464XLAT solution is that it can be made work using the single /64 IPv6 prefix assigned to the UE during the PDN Connection activation, and it also works on pre-Release-8 networks. There is no additional provisioning specific to 464XLAT technology needed. This is because the private IPv4 address used by the UE can be picked up by the CLAT and there is no need to provision it, since every IPv4-embedded IPv6 address the UE may initiate is made unique by the /64 IPv6 prefix assigned to the UE. For IPv4-only DNS resolvers (in applications or in the case of tethering in separate devices, the CLAT needs to implement a DNS proxy [40], because the IPv4-only DNS resolvers obviously have no means of sending DNS queries over the IPv6 transport and the UE does not know anything other than IPv6 reachable DNS servers provisioned to the IPv6-only APN. As said earlier, the 464XLAT works with a single /64 IPv6 prefix for both translated and native IPv6 traffic. In this case the CLAT has to be bound to a specific IPv6 address IPv6 Transition Mechanisms for 3GPP Networks BIH at socket API layer BIH at network layer IPv4 applications IPv4 applications Socket API (IPv4 / IPv6) API translator Ext. name Address Function resolver Ext. name Protocol mapper mapper Address resolver translator mapper TCP/IPv4 TCP/IPv6 Figure 5.10 Bump-in-the-host architecture options [34]. (derived from the PDN Connection assigned /64 IPv6 prefix) for translated IPv6 traffic. Native IPv6 can then use any other address from the same prefix, thus there is the theoretical possibility of an address collision within the UE (or with other devices in LAN in case of tethering). Therefore, the use of DHCPv6 Prefix Delegation (PD) is recommended, and the UE can 