IPv6 and Mobile IPv6 have gained important momentum in 3G community, in particular, in the 3GPP standard body and 3G operators. It is generally believed that a wide-scale commercial deployment of IPv6 and Mobile IPv6 may be first seen in the 3G industry. A typical example is the IPv6 only IP Multimedia Subsystem (IMS) in UMTS Release 5. In addition, Mobile IP has been identified to be the solution to provide mobility control between UMTS and non-UMTS network such as wireless LAN. Introduction of Mobile IPv6 into 3G IPv6 end terminals, however, will have some serious impact on the feasibility of maintaining some important control functions such as Service-Based Local Policy (SBLP) in IMS.

This paper provides an over of IMS and the SBLP functions in UMTS and then a detailed analysis on the potential inter-working problems between Mobile IPv6 and IPv6 based IMS in UMTS. A simple solution is proposed to solve the inter-working problems without impacting the standard IPv6 operations in UMTS.