User's Manual

686 CHAPTER 17: USING 3COM NETWORK DIRECTOR ON A MULTI-SITE NETWORK
By changing the monitoring mode used for remote devices you can
reduce the amount of monitoring traffic that will be generated on the
WAN links, reducing the impact that monitoring has upon these links.
Configurable Discovery Options
In order to discover your network, 3Com Network Director performs a
series of steps in order to find devices, determine their configuration and
calculate how they are interconnected. Most of these steps involve
generating traffic on your network. If you are discovering a remote site
then this will generate traffic on the WAN links on the route to that site.
This increase in utilization can increase the latency of the links and
possibly even cause them to become oversubscribed.
There are various options within the Network Discovery wizard that allow
you to control the discovery of your network. These include selecting the
subnets and IP address ranges that you wish to discover, restricting the
discovery to certain device types and configuring the number of retries
and timeout periods to use. All of these options can be used to reduce
the amount of traffic that a Network Discovery generates and to allow
the discovery process to complete successfully even in situations where
there are unreliable WAN links in the routes to the remote sites.
For more details on the discovery process, see “
Discovering the Network”
on page 91
.
Configurable Monitor Thresholds
Service monitors, such as the IP Ping Service monitor, provide a useful
indication whether devices or services are available and how quick they
are to respond to certain request types. As is discussed above, if the
route to a remote site passes over one or more WAN links with high
latency then the remote devices at that site may naturally respond slower
to requests than local devices.
By increasing the threshold for a service monitor you can increase the
range of response times that 3Com Network Director considers to be
normal, which will prevent 3Com Network Director from incorrectly
reporting these devices as having slow response times.