A method performed by a mobile device to register for cellular data connection service provided by a mobile telecommunications service provider. A non-serving base station can send an over-the-air overload indicator and a backhaul OI. The compounds are generally aryl sulfonamide derivatives and are useful in pharmaceutical compositions, methods for the treatment of CCR9-mediated diseases, and as controls in assays for the identification of CCR9 antagonists. For services that use a particular database, the performance realized by the services is monitored.