e architecture pictures. As described in Chapter 2, the transport plane is completely separate from the user plane. Thus, the transition to IPv6 in the transport plane does not have to happen at the same time as the user plane. In addition, as the operator's internal network is only for the operator network elements, there are extremely few network nodes compared to the network where the UEs are. Practically, this means that the operators have little incentive to transition their internal network infrastructure anytime soon. However, eventually the operator internal infrastructure will be transitioned to IPv6 as well. As mentioned above, the operator internal network needs its own switches and routers, which obviously have to be upgraded to support IPv6 when transition becomes relevant. In addition, the operator's internal network also has its own DNS, and operations and Deploying IPv6 in 3GPP Networks management infrastructure. The operations and management infrastructure has to be updated to support the configuration of the IPv6 addresses to the switches and routers, enabled to support configuration and monitoring over IPv6, and be able to receive monitoring data with IPv6 addresses in it. Though, on paper, this all seems relatively straightforward, the operators may have equipment and software in their operations and management infrastructure which is relatively old. The infrastructure has been created at the same time as the original IP network, and perhaps new features have been added to it over the years. If it has worked well for the operator, there has been little incentive upgrade it. Making a fundamental change like IPv6 transition may not be straightforward. As in all normal IP networks, DNS infrastructure is used within the operator network infrastructure. The network elements will have their own DNS names, and as described in Chapter 2, the APNs are resolved using the DNS. Hence, the DNS has an important role in a 3GPP network. When considering IPv6 transition, DNS has two parts that have to updated 