The term Nagios refers to Nagios Core, which is a technical management version of the tool that requires extensive resources to set up, configure, and manage network nodes. Nagios XI is the simplified version of the tool that is designed for non-technical users. It has a more user-friendly platform that users can view various network parameters and get any information they need on the fly. In terms of how they support business needs, Nagios is used for technical output, for instance, when trying to investigate why a network device is down. Nagios XI is used for enterprise clients who need to report data, justify costs, and present information regularly.