HP Network Direr Software Products manual Outstanding end station stage, Tree Building Stage

100CHAPTER 4: DISCOVERING THE NETWORK

devices may not support remote poll. If either the write community string is not known for a device or it does not support remote poll then the accuracy of the deduced topology may be reduced.

Outstanding end station stage

Not all end stations will be resolved by the Initial Endstation stage. For instance, some ports may have multiple addresses in their bridge tables even though only a single device is attached (if, for example, older addresses not have aged out). Therefore a similar process to the Device Resolution stage is used to locate the switches that have learned the addresses of known end stations. As with the Device Resolution stage it may not be necessary to communicate with all switches since their address tables will have been cached from the previous stages.

Tree Building Stage

This does not require any device access. It is the point at which 3Com Network Director analyzes all the information it has obtained from the previous stages. It builds a tree view of the subnet/multinet, placing end station devices appropriately. It also adds back in any blocked spanning tree links.

Clouds – Unknown Topology

When 3Com Network Director builds the network tree, there may be certain parts where it is unable to exactly determine the network topology. In such cases you will see clouds on your map depicting the areas of uncertainty. Typically these tend to be ports that have seen the addresses of multiple devices, but those learned devices do not provide any further topology information about the network.

For example, there may be a case where a switch port is connected to an unmanaged hub, and that unmanaged hub is directly connected to two end stations (e.g. PCs). The port on the first switch will learn the addresses of the two end stations. It will not learn the address of the hub (because it does not have one) and 3Com Network Director will not detect the existence of the unmanaged hub because it won’t respond to a ping. 3Com Network Director depicts this scenario as follows: