Parablu has no minimum bandwidth requirement.  It will work with whatever bandwidth is available and allowed – it is just that the backup speeds can be faster or slower as a result.  We have several ways to work with customers during deployment to help manage the first set of full backups in a sensitive way without demanding that you increase your network bandwidth.  Once the first full backups are complete, the incremental backups are much smaller in volume and don’t usually impact a business’ existing bandwidth significantly.