In the world of network management products, there are several methods used to inventory computers. Two main divisions are tools which use an agent and those that are agent-less. Many agent-less tools can be excruciatingly slow and/or have numerous issues with computer and security configuration, such as WMI (Windows Management Interface), thus they still require visiting those computers to "fix" problems before they can be audited. This can be very frustrating. Using an agent can circumvent these problems, but often requires hours or days of lengthy deployment.
network inventory over slow connections such as WANs (Wide Area Networks) with little impact on traffic.