sms. 11.4.1.1 Single IP Mobility Mechanism For networks deploying a single IP mobility management mechanism, the statically configured mobility mechanism can be access type and/or roaming agreement specific. The information about the mechanism to be used in such a scenario is expected to be provisioned into the terminal (or the UICC) and the network. IP session continuity between 3GPP and non-3GPP access types may not be provided in this case if there is a mismatch between what the UE expects and what the network supports. For example, service continuity may not be possible if the user switches to a terminal supporting a different IP mobility management mechanism than that provisioned in the network. 11.4.1.2 Multiple IP Mobility Mechanisms IP Mobility management Selection (IPMS) consists of two components [7]: IP mobility management protocol selection between Network Based Mobility (NBM) and Host based mobility (HBM - MIPv4 (Mobile IP) or DSMIPv6 (Dual Stack MIP)). Decisions on IP address preservation if NBM is selected. The IPMS is performed in the following scenarios: The IPMS is performed upon initial attachment to a trusted non-3GPP access or ePDG to decide how to establish IP connectivity for the UE. The IPMS is performed upon handover without optimization from a 3GPP access to a non-3GPP access to decide how to establish IP connectivity for the UE over the trusted non-3GPP access or ePDG. Next Generation Mobile Communications Ecosystem The IPMS is performed upon change of access between a non-3GPP access and a 3GPP access or between two non-3GPP accesses. If the IP mobility management protocol used to provide connectivity to the UE over the trusted non-3GPP access or ePDG is a NBM protocol, then a decision is performed on whether IP address preservation is provided or not as per PMIPv6 (Proxy Mobile IP version 6) specification, and additionally based on the knowledge in the network of UEs capability (if available) to support NBM. 11.4.1.3 Trusted/Untrusted Non-3GPP Access Network Detection During initial a