VLANs that span multiple switches and multiple subnets shows three VLANs spanning three subnets.
In VLANs that span multiple switches and multiple subnets, Switches A, B, and C provide three separate bridge groups, one for each VLAN, and Router A provides routing for inter-VLAN communications.
If Switch A fails, the IP Manager creates (and the Global Manager imports) the following notifications:
One Switch A Down (problem) notification
One Switch A Unresponsive (event) notification
One TrunkCable DownOrFlapping (event) notification
Three Cable DownOrFlapping (event) notifications—assuming Hosts A, B, and C are “managed”
The IP Manager uses the events as symptoms to diagnose the Switch A Down problem. The events will appear in the Impact tab of the Notification Properties dialog box for the Switch A Down problem.Note:
Events that are used as symptoms to diagnose a failure can also be perceived as impacts that result from the failure.
If Switch B also fails, the IP Manager proceeds as follows:
Clears its original Switch A Down notification, creates a new Switch A Down notification, and creates a Switch B Unresponsive notification; the Impact tab of the Notification Properties dialog box for the new Switch A Down problem will list an additional impact: Switch B Unresponsive.
Creates a Switch B Down notification, a Switch B Unresponsive notification, and five TrunkCable/Cable DownOrFlapping notifications; the Impact tab of the Notification Properties dialog box for the Switch B Down problem will list a Switch B Unresponsive impact, five TrunkCable/Cable DownOrFlapping impacts, and a Switch A Unresponsive impact.
The Switch A and B Down notifications claim that each switch is responsible for the associated failure of the other. In this example, the switches have an impact on each other because they are members of the same set of VLANs: VLAN-1, VLAN-2, and VLAN-3.
Creating a VLAN impact propagation group that allows VLAN-1, VLAN-2, and VLAN-3 to become members of the group will prevent the linking of the Switch B Unresponsive impact to the Switch A Down problem, and will prevent the linking of the Switch A Unresponsive impact to the Switch B Down problem.