Over the last few years, novel architectures like ad hoc and sensor networks have introduced new challenges in the way the communication infrastructure must be addressed. Unlike traditional approaches, these architectures require the complete self-organization of nodes as well as the support of mobility. A common problem encountered in such networks is the fundamental requirement of guaranteeing the connectivity between nodes. A number of network functionalities have then to be reassessed, where two components must receive particular attention: topology control and node localization. In this paper, we survey the current state of the art for these domains and identify some open issues for future research and development.