Voice Core Network (VCN)

In a 3GPP network, voice telephony services are traditionally provided by through a Mobile-Services Switching Centre (MSSC) and supported infrastructure. This can also be provided through an IP Multimedia System (IMS).

IMS relies heavily on IP protocol. According to 3GPPP standards, IMS should be based on IPv6, which avoids future IPv4-to-IPV6 migration requirements.

Though new IMS-compliant equipments will typically be deployed using IPv6, existing voice core equipments will still be utilizing IPv4.

The voice core IPv4 to IPv6 migration is a complex task, which requires the cooperation of various protocols and layers. Therefore alleviating the IP address consumption is one of the primary motivations for the IPv4 to IPv6 migration.

Due to the facts that the voice core migration from IPv4 to IPv6 is a complicated task and the end-user devices have almost consumed all IP addresses, it may not be feasible to migrate the entire 3GPP voice core of operators from IPv4 to IPv6. However instead, it would be feasible to perform such migration within the voice core at specific interfaces.

An operator, for instance, may wish to leave intra-call server MGW and all Iu-CS(IP) interfaces to the MGW traffic as IPv4 transfers all inter-call server MGW to MGW traffic using IPv6. This type of architecture requires dual stack capable MGWs only to be on the network bound interfaces and would doesn't require IPv6 capable RNCs.

For the LTE requirements, the carrier may dictate that the device to be assigned an IPv6 address whenever it attaches to the LTE network.

Through the LTE migration, Ipv6's adoption will become increasingly important due to the fact that they will require more IP addresses for all the network connected devices. Therefore the number of unused IPv4 addresses will be reducing more and more, which requires a new standard to address new waves of data-capable devices.