A tremendous amount of research has been done toward improving transport-layer performance over wireless data networks. The improved transport layer protocols are typically application-unaware. In this paper, we argue that the behavior of applications can and does dominate the actual performance experienced. More importantly, we show that for practical applications, application behavior all but completely negates any improvement achievable through better transport layer protocols. In this context, we motivate an application-aware, but application transparent, solution suite called A 3 (application-aware acceleration) that uses a set of design principles realized in an application-specific fashion to overcome the typical behavioral problems of applications. We demonstrate the performance of A 3 through both emulations using realistic application traffic traces and implementations using the NetFilter utility.