LANsurveyor can diagram both small and large networks. Customers have shared success stories about maps with more than 2000 routers and 4000 switches.
If you are mapping a large network, you may have some challenges visualizing your network completely on your computer. This Appendix provides tips for adjusting the LANsurveyor diagram to best match your requirements.
Full Discovery
Check to make sure your routers and switches were discovered and mapped. Use the left-hand navigation to see the list of routers and switches/hubs LANsurveyor discovered.
Use the Map Level 1 icon to redraw the map and display just your routers and network segments.
If LANsurveyor discovers over 300 routers, by default the map will display in Level 1. You can change the default in the LANsurveyor Preferences. You can also use the LANsurveyor preferences to display only selected nodes by type, for example just Responder clients.
Click the Level 2 icon to show network segments, routers, and switches.
Display nodes connected to a router using with the Show Sub-Level icon. Click a router (or managed switch), then click the Show Sub-Level icon to display the attached nodes.
If your map still has too many nodes, you can right-click a router and select Focus in New Window. This allows you to "drill down" on any specific router and see its connections in a completely separate map window. You can still do Level 1, 2, and 3 displays of that new map, print it, and export it to Visio.
Map Overview
The Map Overview icon 
opens a new window with a very small zoom percentage and a rectangular selection that allows you to move to different areas of the map quickly. Use the Map Overview in conjunction with the zoom percentage and the left-hand navigation to quickly move to specific routers or switches--just click the node you want to center on the map.
LANsurveyor map generation creates very little network overhead. To get the most accurate maps possible, turn on Continuous Scan and let LANsurveyor make a few passes at creating the map during periods of normal network activity.
A lot of information is gathered from routers and switches. If there's no network activity, it will be impossible to determine the exact connectivity for your network.