Often you have more machines than licenses.
With this feature you can tell RR how many licenses it should use.
This can be used for the pre-defined applications with their renderer.
But you can also add your own render licenses.
For example Realsmart or Furnace licenses.
The render licenses a job needs are displayed at the rrSubmitter in the Scene Information box.
Temporal reduction of licenses:
If the client finds a license error message in the render log, then the server reduces the render licenses for this application for one hour.
In case you are using one license interactively.
Each hour the server tries to resend a job to check if the license is available again.
Manual reduction of licenses:
If an artist requires a license for work, you can manually reduce the number of render licenses.
The commands are available via rrControl page "global info".
You can either manually return the license, otherwise it follows the rules of the automatic temporal reduction as described above.