HP Network Direr Software Products Some devices are the wrong type, There are clouds in my map

Useful Information and References 141

time if it or the network is very busy, or potentially may not receive, or be able to respond to, the ICMP ping message if it is placed beyond a firewall. If a device fails to respond to a ping then 3Com Network Director will not add it in to the map as an IP device (although it may still be added as a MAC-only device).

If a device responds to a ping, 3Com Network Director then attempts to determine if it supports other protocols, in particular SNMP. See “Device Capability Detection ” on page 93. If the device supports SNMP, it reads the IP address table to establish if the device has any additional IP addresses. If any of those addresses conflict with the addresses of another device then one of the two nodes may be discarded.

It is possible to inadvertently assign duplicate IP addresses to some devices. Certain 3Com devices provide resilient management by allowing you to assign an IP address to each of the units in a stack. If you reconfigure your network and move a unit from one stack to another, if the unit has been assigned an IP address, then that address will move with it. If you do not want the address to move you should delete the IP address from the unit when you transfer it.

Some devices are the wrong type

SNMP-capable devices can appear as generic IP icons on the map if the wrong read community string was specified for the device or if SNMP requests to the device timed-out.

If a device appears as a generic SNMP icon it usually means that 3Com Network Director does not recognize the sysObjectID returned by the device. 3Com Network Director only recognizes a limited number of third party sysObjectIDs.

All 3Com devices should be recognized by 3Com Network Director. However, for new devices that have been released after the version of 3Com Network Director you are using, the devices may be shown as Generic SNMP or 3Com Device. In this case you should check the 3Com web site for 3Com Network Director service packs that support these newer devices.

There are clouds in my map

If 3Com Network Director cannot deduce exactly how devices are connected together it sometimes creates clouds during topology process. This is quite common with third party devices, particularly hubs. Wireless