Vor seinem Beginn ist die ordentliche Kündigung des Vertrages für beide Vertragsteile ausgeschlossen.

The (ordentliche) termination of this contract before the beginning of employment is prohibited for either party.

This is from an employment contract in the section on beginning of employment and probationary period. I'm not familiar with any concept like "proper" or "ordinary" (ordentlich) termination of a contract. Does anyone know what this refers to?

Also, just to make sure, do I have the right sense of this sentence?