During a KNMsetup.exe install you are asked to select one of the following options. The Distributed and Gateway options only apply if you are monitoring multiple subnets.
Standard - Selected by default. If monitoring a single subnet, select this option. Recommended for first time evaluations.
Distributed - If monitoring multiple subnets, select this option if installing the server all gateways send data to.
Gateway - If monitoring multiple subnets, select this option if sending data to a distributed server.