HP Network Direr Software Products manual Monitoring State and the Grouped View

276CHAPTER 7: MONITORING THE NETWORK

For details on how to start monitoring an unmonitored device or link, or to stop monitoring a monitored device or link, see “Starting and Stopping Monitoring” on page 293.

For more information on event severities see “Event Severities” on page 321

Monitoring State and the Grouped View

When you are viewing the devices in your network grouped by subnet, 3Com Network Director propagates the monitoring states of devices, links and submaps up the submap hierarchy.Each submap is colored to indicate the most critical monitoring state of the devices, links or submaps that it contains.

For example, if a subnet contains two devices, one of which has a red monitoring state and one of which has a yellow monitoring state, the subnet will be colored red. If the event causing the red device's monitoring state is subsequently resolved, the subnet will change to be colored yellow, as this is now the most critical monitoring state contained within the subnet.

When determining the monitoring state of a submap, 3Com Network Director ignores any map items or links that are visible at a higher level in the hierarchy than the submap itself.For example, the monitoring state of a router will not affect the monitoring state of the subnets that it is present on, as the router is visible in the top-level map, which is the highest level in the hierarchy.

Monitoring 3Com Network Director uses various techniques to monitor the state of Techniques devices and links within your network.The techniques used for a

particular monitor depend upon the feature that is being monitored, and can be broadly broken down into active and passive monitoring:

Active Monitoring: Active monitoring works by 3Com Network Director polling, and possibly retrieving data from, a device on a regular basis.Once the device has been polled, or once the data has been retrieved from the device, 3Com Network Director can analyze the results to determine the state of the device.There are various mechanisms used for active monitoring, including sending IP pings, retrieving data from SNMP MIBs, and directly checking for service availability.