Rodrigues, LuisGuerreiro, JoelCorreia, Noélia2021-11-052023-07-0120210140-3664http://hdl.handle.net/10400.1/17295Sensor networks can be federated for wide-area geographical coverage using RELOAD/CoAP architectures. In this case, proxy nodes of constrained environments form a P2P overlay to announce device resources or sensor data. Although this is a standard-based solution, consistency problems may arise because P2P resources (data objects stored at the overlay network) may end up including similar device resource entries. This is so because device resource entries, or sensor data, can be announced under different P2P resource umbrellas, meaning that any update to them will require changing multiple P2P resources. Here in this article, a multi-layer approach is proposed to solve this issue, allowing for a more efficient storage/retrieval of IoT data. Information at the overlay network is kept consistent, although additional P2P anonymous resources must be created. A mathematical model is proposed for the planning of such multi-layer organization of P2P resources, together with a heuristic algorithm. A required overlay service is also discussed.engFederated networksSensor networksRELOADCoAPCoAP usagejournal article10.1016/j.comcom.2021.07.019