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Scheduling a Maintenance Event on Network Elements


Before you bring down devices in your managed network to perform updates or other configuration tasks, you can schedule a maintenance event from the NorthStar Controller so that selected nodes, links, or Shared Risk Link Groups (SRLGs) will be brought down during a specified period of time. During the maintenance event, NorthStar will reroute the affected LSPs around the down elements before initiating the maintenance event.


When you run simulation on a maintenance event, the NorthStar Controller takes the current network state into consideration, including any other network elements that are currently down. However, any network elements that are down as a result of other maintenance events are not taken into consideration. So if you simulate Event B while another simulation event (Event A) is in progress, the logically down elements from Event A are not taken into consideration when you run Event B simulation.

This topic describes the steps required to create and schedule a maintenance event on selected nodes, links, SRLGs, or interfaces.

To schedule a maintenance event on selected network elements:

  1. From the Network Info window, select Maintenance > Add.

    The Add Maintenance Event window is displayed.


    You can also reach the Add Maintenance Event window by navigating to Applications > Maintenance.

  2. In the Maintenance Event Name field, enter a name for the maintenance event.

    This field is required.


    The name you specify can also be used for the file extension name for generating reports.

  3. In the Owner field, type admin for the owner.
  4. In the Comment field, enter a name for the maintenance event you are creating.
  5. In the Starts field, click the calendar icon on the right and select the date and time to initiate the maintenance event (at least a few minutes after the current server time).

    This field is required.

  6. In the Ends field, click the calendar icon on the right and specify the estimated date and time the maintenance event ends. Note

    The minimum duration for a maintenance event is 5 minutes.


    The NorthStar Controller displays the estimated time but does not impose an end time for a maintenance event.

  7. Select the Auto Complete at End Time option to automatically complete the maintenance event at the specified end time.

    Otherwise, you must select the Change Status to Completed option to manually complete the maintenance event, after it finishes.


    The Auto Complete option should be used only when you are certain that the maintenance event will finish on time. Maintenance events that are in progress require the user to manually change the operation status to “Complete” in order to signal the end of the maintenance event. Manually ending the event can be done at any time. Note that the maintenance event will not stop at the specified end time until the user manually intervenes by changing the status. When you select the Auto Complete option, the NorthStar Controller automatically signals the end of the maintenance event at the specified end time, without user intervention.

  8. Use the Node, Links, or SRLG tabs to select the elements to include in the maintenance event:

    1. Select elements in the Available column and click the right arrow to move them to the Selected column. Click the left arrow to deselect elements.

    2. Click Submit when finished. The new maintenance event appears in the Network Information table at the bottom of the Topology view.

  9. When the scheduled maintenance event completes (and the Auto Complete option is not selected), manually change the Operation Status from the Maintenance tab by right-clicking Change Status to Completed on the selected maintenance event. Note

    If its operational status is not changed upon completion of the maintenance event, the maintenance will never end, and those elements under maintenance will be considered “down”.


    When maintenance events complete, tunnels are routed to the optimal path of the current network state, but that path is not necessarily the original path.

You can evaluate the effects of a maintenance event using the Simulate Maintenance Event function. To access this function, right-click in the maintenance event row in the Network Information table and select Simulate as shown in Figure 1.

Figure 1: Accessing the Simulate Maintenance Event Function
Accessing the Simulate
Maintenance Event Function

The Maintenance Event Simulation window, as shown in Figure 2, displays the nodes, links, and SRLGs you selected to include in the event.

Figure 2: Maintenance Event Simulation Window
Maintenance Event Simulation

The Exhaustive Failure Simulation section at the bottom of the window is optional. It provides check boxes for selecting the element types you want to include in an exhaustive failure simulation. If you do not perform an exhaustive failure simulation (all check boxes under Exhaustive Failure Simulation are cleared), all the nodes, links, and SRLGs selected for the maintenance event fail concurrently. In Figure 2, for example, node 0110.0000.0199, link L11.106.107.1_11.106.107.2, and SRLG 100 would all fail at the same time.

Using this same example, but with Nodes selected under Exhaustive Failure Simulation, the simulation still fails all the maintenance event elements concurrently, but simultaneously fails each of the other nodes in the topology, one at a time. If you select multiple element types for exhaustive failure simulation, all possible combinations involving those elements are tested. The subsequent report reflects peak values based on the worst performing combination.

Whether or not you select exhaustive failure, click Simulate to perform the simulation and generate a report. You can view the report using the Applications menu by navigating to Applications>Reports.