  In this paper we discuss the state of the art of (mobile) multi-hop ad hoc
networking with the aim to present the current status of the research
activities and identify the consolidated research areas, with limited research
opportunities, and the hot and emerging research areas for which further
research is required. We start by briefly discussing the MANET paradigm, and
why the research on MANET protocols is now a cold research topic. Then we
analyze the active research areas. Specifically, after discussing the
wireless-network technologies we analyze four successful ad hoc networking
paradigms, mesh, opportunistic, vehicular networks, and sensor networks that
emerged from the MANET world. We also present the new research directions in
the multi-hop ad hoc networking field: people-centric networking, triggered by
the increasing penetration of the smartphones in everyday life, which is
generating a people-centric revolution in computing and communications.
