ght get confused. However, there is one small issue in this approach. Prior Release-8, 3GPP specification did not explicitly spell out that APNs may overlap name-wise when the PDP types differ. There are old GGSNs that cannot support two APNs with the same name, but different PDP type, in the same box. All-in-one APN An existing APN is re-configured into the networks as an all-in-one APN. This means the same APN serves IPv4-only subscribers, IPv6-only subscribers, and dual-stack subscribers. The APN information in the HLR/HSS subscription profiles may then be re-provisioned on an opt-in basis or as a mass rollout. Then the selection of the used PDP or PDN type is a combination what the UE asks for and what is provisioned in the subscription profile. This approach works nicely when the operator knows that the rest of the network is dual-stack capable throughout and UEs are also up to date. The selection of the PDP or PDN type can also be controlled per subscriber by using the backend AAA infrastructure. There are many possibilities to override what the UE asked for based on various pieces of information available in the (S)Gi AAA interface profile. See Section 4.4 for more details. Dedicated IPv6-enabled GGSN or PGW Specifically, in roaming cases it might make sense to dedicate a GGSN or a PGW only for inbound roamers. The GGSN, or the PGW, would have a plain configurations with for example, IPv4-only APNs. The same APNs could be IPv6 enabled when the UE is not roaming, and gets anchored to a different GGSN or PGW. In this way, roaming users can be turned IPv6-less without any kind of provisioning in the subscription profiles or UEs. 5.5.4 Translation Implications Today, still relatively in the beginnings of the transition, there are many services in the Internet that are only accessible over IPv4. If an operator would like to move many of its customers to IPv6, the operator may choose to provide IPv6-only access to the subscribers, and translate between IPv6 and IPv4. Translating between IPv6, and IPv4 has its im