Global operators and service providers that want to benefit from Fixed/Mobile Convergence (FMC) and mobile/Wi-Fi convergence (MWC) are paying close attention to Unlicensed Mobile Access (UMA). UMA is a relatively new technology that is being compared with IP Multimedia Subsystem (IMS), which has caused some confusion in the marketplace because there is little understanding of how these technologies compete or coexist. UMA is the standard provided by the 3rd-Generation Partnership Project (3GPP) for enabling access to mobile services over Wi-Fi and broadband IP networks. It transforms existing wireless LANs (WLANs) into seamless extensions of mobile wireless networks and allows subscribers to roam automatically between cell networks and home, office, or public WLANs, providing total access to all applications regardless of location. UMA was created to leverage existing standard interfaces so the technology would have a minimal impact on the core networks that operators already had in place. It was also designed to provide access layer mobility to circuit services (CS) and packet services (PS). This makes Wi-Fi and IP seamless extensions of an operator's network. UMA was also designed to eliminate the cost and performance barriers that limit fixed-to-mobile substitution in homes and offices. UMA ensures that users have a consistent mobile experience and that operators have little disruption on their networks.