102CHAPTER 4: DISCOVERING THE NETWORK
Figure 24 Edge Switch – Unknown Topology
You can identify which switch is the problem device here by checking if unit and port information has been successfully retrieved for each link to each switch. Hover the mouse over the end of the link nearest each switch to show tooltip information on the link. The switch with missing unit and port information is probably the cause of the problem. In the situation above, it is clear that the bottom switch is at fault.
If information was available, the problem switch would be positioned where the cloud is, and the cloud would not be shown. The above situation occurs because the switch to the left of the diagram has learned the addresses of all the end stations, and also the bottom switch. However, because 3Com Network Director lost communication with the bottom switch, it also gets treated as if it were an end station (since topology information could not be read from it).
If a problem was encountered when communicating with the switch you should see an error in the Discovery report produced by 3Com Network