HP Network Direr Software Products manual Initial Endstation stage, Device Resolution Stage

Key Concepts 99

Initial Endstation stage

During this stage an attempt is made to identify the ports that have only learned a single address. This is done by reading bridge address tables. The purpose of this stage is two-fold:

■to eliminate the need for many end station addresses having to be considered in the rest of the topology, which can reduce the amount of processing and network traffic generated in the remainder of the topology process;

■to detect the existence of non-IP (MAC-only) nodes. If a port has a functioning link and has learned exactly one MAC address then that address is assumed to be a single node attached to that port. If no IP address was found to map to this MAC address during the IP to MAC Resolution stage then 3Com Network Director will assume that this MAC address belongs to a new node. Consequently 3Com Network Director will show the MAC-only node on the map.

You may have deliberately instructed the discovery operation to only detect IP ranges relevant to your switches which are outside the ranges of your endstations. Consequently the depiction of MAC-only nodes may not be required. You can prevent MAC-only nodes from being added to your map by selecting the Only core devices or Only IP devices in the Discovery Options pane of the Network Discovery Wizard. See “Discovery Options Pane” on page 122 for more information.

Device Resolution Stage

During this stage 3Com Network Director attempts to establish which switches have learned the addresses of other switches, and on which ports. Since some addresses have already been read from the bridge tables in the previous stage, 3Com Network Director may not need to communicate with all switches during this stage.

At the end of this stage, 3Com Network Director analyses whether it has enough information to determine the network topology.

Remote Poll Stage (directed pings)

If insufficient information was obtained from the Device Resolution stage, then an attempt is made to force devices to learn the addresses of others by instructing them to ping each other (remote poll).

As with the previous remote poll stage the write community string of the relevant switches is required. Also, as with the previous stage some