A user equipment (UE) in a communication system, and a method thereof. The method includes establishing; by a user equipment (UE), a first data connection associated with an access point name (APN); receiving, by the UE, a session management back-off time value when a request of a bearer resource modification or a bearer resource allocation for the established first data connection is rejected; starting, by the UE, a session management back-off timer according to the session management back-off time value, the session management back-off timer being associated with the established first data connection; if the UE receives a deactivate bearer context request message indicating that reactivation is requested, stopping the session management back-off timer if the session management back-off timer is running; and establishing, by the UE, a second data connection associated with the APN after stopping the session management back-off timer.