The Internet has evolved during the last decade, reaching a larger number of users and encompassing several new technologies. New classes of hosts such as mobile devices are gaining popularity, while the transmission media become more heterogeneous. Wireless networks exhibit different characteristics than wired ones. Mobile hosts have different needs and limitations than desktop computers. TCP has served well the wired Internet for almost 20 years, but is not ready for wired-cum-wireless environments. This article presents the challenges that must be met in order to provide reliable transport services to all hosts regardless of the type of network connectivity used. It surveys recently proposed solutions and evaluates them with respect to a wired-cum-wireless environment.