User's Manual

Key Concepts 685
Configurable Poll Rates for Active Monitoring
When you are monitoring a device using an active monitoring technique
(i.e. either full or response monitoring mode), 3Com Network Director
polls the device on a regular basis with requests for device state
information. The more frequently 3Com Network Director polls the
device, the more management traffic it will generate to that device and,
assuming the device is responding to request, the more traffic the device
will generate in response.
If an actively monitored device is a remote device then the more
frequently that device is polled, the more traffic will be generated on the
WAN links on the route to that site as a result of the monitoring. If a
large number of remote devices are being monitored, particularly if they
are being monitored in full monitoring mode, then frequent polling can
generate a large amount of traffic over the WAN links. This may result in
higher latency on these links, and may even lead to the links becoming
oversubscribed.
To avoid this situation, 3Com Network Director allows you to control the
rate at which actively monitored devices are polled. By decreasing the
poll rate you can reduce the amount of traffic generated by active
monitoring.
See “
Monitoring Techniques” on page 276 for more details of active
monitoring and “
Monitoring Mode” on page 296 for more details of full
and response monitoring modes.
Configurable Monitoring Modes
3Com Network Director has different monitoring modes that it can use to
monitor the devices in your network. These monitoring modes vary in
the level of detail they can provide you about the state of the devices in
your network, and also vary in the level of traffic they generate on your
network.
When monitoring a single site network the level of traffic generated by
the monitoring process is not normally an issue. However, when
monitoring a multi-site network large amounts of monitoring traffic to
and from remote sites can increase the latency of WAN links, possibly
even causing them to become oversubscribed.