In the last years both academia and industry have worked toward new Internet architecture proposals, due to the awareness that the current architecture is facing unforeseen scalability issues, concerning the restless increase of the BGP routing tables, addressing, mobility, multihoming, and inter-domain traffic engineering. The general consensus is that splitting the locator and identifier roles of IP addresses solves these issues and is necessary for the Future Internet architecture. However, in practice, several constraints have to be taken into account in order to design a viable solution that can be incrementally deployed, without disrupting the existing communication infrastructure, whilst providing benefits, hence incentives, for early adopters. An instance of such a paradigm is the Locator/ID Separation Protocol (LISP). LISP was first proposed by Cisco in the IRTF (Internet Research Task Force) and is now under development in the IETF (Internet Engineering Task Force). Aiming at being incrementally deployable, LISP has evolved from its initial design in order to accommodate the constraints that the current Internet imposes, but still offering an effective solution for the scalability issues. Our goal is not to convince the reader about the merits of LISP, or the general Locator/ID Split paradigm, and neither to provide numerical results of its performance. Rather, the talk aims providing an overview on how LISP works and what are the basic principles, including its implementation aspects.