At the 2005 GSM World Congress in Barcelona, the telecommunications world was introduced to the concept of fixed-mobile convergence (FMC), which is the ability to seamlessly transition calls between unlicensed Wi-Fi networks and licensed carrier networks. Based on the 3GPP/3GPP2 IP multimedia subsystem (IMS) network architecture standards, FMC was touted as a hook to lure consumers and enterprises away from the incumbent cellular providers to landline-based Wi-Fi service providers, or for integrated carriers to stay competitive against the emerging Wi-Fi service providers.