Wireless sensor networks (WSNs) have gained momentum as a technology for monitoring and control applications in a plethora of scenarios. Some examples include home automation, industrial control and environmental monitoring. In fact, these networks may enable the futuristic paradigm called ambient intelligence. Despite the challenges that present these networks, a variety of solutions (many of which are proprietary) have emerged. In parallel, the Internet Engineering Task Force (IETF) is devoting a lot of effort to the development of standard networking solutions for WSNs based on the Internet Protocol (IP). This work will allow straightforward interoperability between WSNs and the Internet and will also constitute a significant step towards the ‘Internet of Things’.