The whisper net is just the syncing of your content from one device to the other.
You can also connect your Kindle Paperwhite to your computer:
Plug the larger end of the USB cable into an available USB port or a powered USB hub connected to your computer, and connect the other end of the USB cable to the micro-USB port on the bottom of the Kindle Paperwhite.
When connected to the PC, the Kindle Paperwhite goes into USB drive mode and its battery is recharged by the computer. Wireless service is temporarily shut off. The Kindle isn’t usable as a reading device while in USB drive mode but returns to your reading location when you eject the device from your computer.
When your Kindle Paperwhite is connected, simply drag and drop (or copy and paste) the file from your computer’s hard drive to the Kindle Paperwhite.