22.2283GPPRelease 16Service requirements for the Internet Protocol (IP) multimedia core network subsystem (IMS)Stage 1TS
The Operator of an IMS infrastructure may base the implementation on IPv4 only, IPv6 only or both. The choice is an operator option.
The IMS may support UEs using IPv4 only, IPv6 only or both at an IP-based User-Network Interface. The choice is an operator option.
9.2 IP addressing for cdma2000 access to IMS
The IMS may support UEs using simultaneous multiple IP addresses.