Information About the IP SLAs Multioperations Scheduler
Normal scheduling of IP SLAs operations allows you to schedule one operation at a time. If you have large networks with thousands of IP SLAs operations to monitor network performance, normal scheduling (scheduling each operation individually) is inefficient and time-consuming.
Multiple operations scheduling allows you to schedule multiple IP SLAs operations using a single command through the command-line interface (CLI) or the CISCO-RTTMON-MIB. This feature allows you to control the amount of IP SLAs monitoring traffic by scheduling the operations to run at evenly distributed times. You must specify the operation ID numbers to be scheduled and the time range over which all the IP SLAs operations should start. This feature automatically distributes the IP SLAs operations at equal intervals over a specified time frame. The spacing between the operations (start interval) is calculated and the operations are started. This distribution of IP SLAs operations helps to minimize the CPU utilization and enhances the scalability of the network.
The IP SLAs multiple operations scheduling functionality allows you to schedule multiple IP SLAs operations as a group, using the following configuration parameters:
- Group operation number—Group configuration or group schedule number of the IP SLAs operation to be scheduled.
- Operation ID numbers—A list of IP SLAs operation ID numbers in the scheduled operation group.
- Schedule period—Amount of time for which the IP SLAs operation group is scheduled.
- Ageout—Amount of time to keep the operation in memory when it is not actively collecting information. By default, the operation remains in memory indefinitely.
- Frequency—Amount of time after which each IP SLAs operation is restarted. When the frequency option is specified, it overwrites the operation frequency of all operations that belong to the group. When the frequency option is not specified, the frequency for each operation is set to the value of the schedule period.
- Life—Amount of time in which the operation actively collects information. You can configure the operation to run indefinitely. By default, the lifetime of an operation is one hour.
- Start time—Time when the operation starts collecting information. You can specify an operation to start immediately or at an absolute start time using hours, minutes, seconds, day, and month.
The IP SLAs multiple operations scheduling functionality schedules the maximum number of operations possible without aborting. However, this functionality skips those IP SLAs operations that are already running or those operations that are not configured and therefore do not exist. The total number of operations are calculated based on the number of operations specified in the command, irrespective of the number of operations that are missing or already running. The IP SLAs multiple operations scheduling functionality displays a message that shows the number of active and missing operations. However, these messages are displayed only if you schedule operations that are not configured or are already running.
A main benefit for scheduling multiple IP SLAs operations is that the load on the network is reduced by distributing the operations equally over a scheduled period. This distribution helps you to achieve more consistent monitoring coverage. Consider configuring 60 operations to start during the same 1-second interval over a 60-second schedule period. If a network failure occurs 30 seconds after all 60 operations have started and the network is restored before the operations are due to start again (in another 30 seconds), this failure would never be detected by any of the 60 operations. However, if the 60 operations are distributed equally at 1-second intervals over a 60-second schedule period, then some of the operations would detect the network failure. Conversely, if a network failure occurs when all 60 operations are active, all 60 operations would fail, indicating that the failure is possibly more severe than it really is.
Operations of the same type and same frequency should be used for IP SLAs multiple operations scheduling. If you do not specify a frequency, the default frequency is the same as that of the schedule period. The schedule period is the period of time in which all the specified operations should run.