It cannot discover devices across routers, an operation which would require Internet Protocol level routing.
The LLTD Mapper I/O component is the master module which controls the discovery process and generates the Network Map.
In addition to illustrating the layout of a network with representative icons for the hosts and interconnecting lines, each device icon may be explored to produce a popup information box summarizing important network and host parameters, such as MAC address and IP address (both IPv4 and IPv6).
If the device has reported the presence of a management Web interface, clicking on the icon will open a HTTP session to the host.
A royalty free Linux sample implementation of the LLTD responder is available from Microsoft as part of the Windows Rally Development Kit.