An example method stores a nomadic service designator and an operating mode designator in association with a public user identifier. The nomadic service designator indicates whether an IP device is allowed to access VoIP services from different network locations. The public user identifier facilitates establishing a call with the IP device. The operating mode designator indicates when the IP device is in a suspended operating mode and an unrestricted mode. The suspended operating mode restricts the IP device to a subset of communication services associated with a service subscription of the IP device, and to a 911 service. The unrestricted operating mode is based on a registered geographic location associated with the IP device being a current geographic location of the IP device, and is based on a service provider being able to provide an E911 service including a location-identification service at the current geographic location of the IP device.