Nodes are computers running the Elrond software, so they contribute to the Elrond network by relaying information and validating it. Each node needs to stake 2.500.000 ERD to become a Validator and is rewarded for its service. Nodes without a stake are called Observers - they are connected to the network and relay information, but they have no role in processing transactions and thus do not earn rewards.
100Mbit/s always-on internet connection
Linux OS (Ubuntu 18.04 recommended) / MacOS