When you add the Node to UDT it lets you select which ports to monitor. Just add the node but dont select any ports. By adding your layer three switches/routers UDT will be able to associate MAC addesses with IPs. I do this exact thing. I do not monitor core ports but have the core switches in UDT. I monitor closet switches with all the ports added. Also if you have a wireless lan controller add that to UDT also that way you will see you wireless clients too.