User's Manual

Key Considerations 315
data collection, the graph should start showing the monitor’s state
history.
Switched Off: The monitor is disabled and so no data is being gathered
for it.The monitor may be re-enabled from within the Live Graphs
window by selecting it and selecting Monitor > Enable this monitor.See
“
Disabling and Enabling Individual Monitors” on page 294 for more
information.
Data Unavailable: The monitor has been started, but is unable to
fetch the data it needs to operate.
This may occur if 3Com Network Director is unable to authenticate with
the device to retrieve the monitor data.For example, the wrong SNMP
community strings may be configured for the device.You can change the
security settings that 3Com Network Director uses for a device from the
Security tab of the Properties dialog box for the device. See “
Viewing
Device Details” on page 229 for more information.
This may also occur if the device does not provide the data required for
the monitor.This commonly occurs when you first turn on monitoring for
an end station or server. 3Com Network Director will attempt to monitor
several services on these devices, such as FTP and HTTP, most of which
may not be supported by the device.
Data Unavailable is also displayed for the Utilization monitor of a WAN
link if a speed could not be determined for the connection in one or both
directions. You can set the speeds for both directions of a WAN link from
the General tab of the Properties dialog box for the link. Setting the
speeds will automatically start monitoring for a Utilization monitor in this
state if the link is being monitored.
A monitor in the Data Unavailable state is not generating any traffic on
the network, so may be safely ignored.
Problems Starting
Monitoring for a
Device or Link
There are some devices and links that 3Com Network Director cannot
monitor:
Devices Without IP Addresses: Due to the techniques used to monitor
devices, 3Com Network Director uses device IP addresses to perform
monitoring.If a device does not have an IP address assigned to it, or if
3Com Network Director was unable to determine its IP address during
Network Discovery, then 3Com Network Director will not be able to
monitor it.