Advances in micro-electro-mechanical systems (MEMS) technology, wireless communications and digital electronics have enabled the development of low-cost, low-power, multi functional sensor nodes that are small in size and communicate untethered in short distances. Majority of sensor applications imply the deployment of a large number of nodes, communicating wirelessly and therefore forming a Wireless Sensor Network (WSN). A direct consequence of such a large number of nodes expected to be deployed is their low-cost requirement. This implies minimal processing and memory capabilities, with a very long life time which requires small energy consumption. WSNs have been under study by the academic community for a number of years, and a number of different solutions has arisen. One of the key challenges to their deployment is routing. Accordingly, the main topic of the training was to perform a thorough study of the two routing protocols - RPL and LOADng - through simulations and tests of different scenarios of interest. For that purpose, an event-driven Operating System called ''Contiki'', developed specifically for memory constrained devices such are sensor nodes, was used in order to emulate the software executing on individual nodes. The ''Cooja'' simulator, part of the Contiki project, was used as an event generator, in order to evaluate the two protocols in different scenarios and topologies.