The technology pertains to wireless telecommunications systems in which a quality of service is handled for a service provided to a user equipment when the user equipment transitions from being served by a source network to being served by a target network. The quality of service is handled even if the source and the target networks implement proprietary QCIs. In general, a source QCI, which may be proprietary to the source network, is remapped to a predetermined QCI that identifies a set of predetermined QCI characteristics whose values are similar to the source QCI characteristics identified by the source QCI. The predetermined QCI and the set of predetermined QCI characteristics are used by the target network to provide the service to the user equipment after the transition.