In this survey we focus on open issues of the wireless Internet. Our main intention is to elaborate what has to be done to integrate mobile devices in the Internet in such way that users do not experience any difference between wireless and fixed connections. We concentrate on the layers on top of IP, i.e. transport protocols, middleware platforms and applications. We provide an overview of existing solutions and a discussion of open issues andpromising research directions is given for each of these fields. q 2004 Elsevier B.V. All rights reserved.