User's Manual

684 CHAPTER 17: USING 3COM NETWORK DIRECTOR ON A MULTI-SITE NETWORK
while traversing the network, or if the device the request is sent to is not
responding for some reason, then a response to the request will never be
received by 3Com Network Director.
In order to determine when this situation has occurred, 3Com Network
Director uses the standard timeout technique: if a response is not
received to a request within a certain period of time (known as the
timeout period), 3Com Network Director concludes that there will not be
a response to that particular request.
If the route to a remote site passes over one or more WAN links that have
a very high latency then some, or even all, requests to that remote site
may time out. This would prevent 3Com Network Director from
monitoring and managing that site properly. By increasing the timeout
period you can increase the time that 3Com Network Director will wait
for a response to each request, preventing incorrect timeouts from
occurring and so allowing 3Com Network Director to monitor and
manage that site.
Configurable Retries
If a request sent by 3Com Network Director times out then this may be
due to either the request or the response being dropped while traversing
the network. As a result, 3Com Network Director cannot immediately
conclude that a device is not responding if it fails to respond to a request.
To cope with this situation 3Com Network Director uses the standard
technique of sending retries: if a timeout occurs for a request then 3Com
Network Director will try sending the request and waiting for a response
a second time. Depending upon the protocol, it may retry the request
multiple times before concluding that the device is not responding.
If the route to a remote site passes over one or more WAN links that are
oversubscribed then some, or even all, requests to or responses from that
remote site may be dropped by the routers at either end of the
oversubscribed links. By increasing the number of retries you can increase
the number of attempts 3Com Network Director will make with each
request before concluding that the device it is destined to is not
responding. This will increase the likelihood that requests sent to devices
at the remote site will succeed.