So the Tethering data flow isTethering is connecting one device to another. In the context of mobile phones and tablet computers, tethering allows sharing the Internet connection of the phone or tablet with other devices such as laptops. Connection of the phone or tablet with other devices can be done over wireless LAN (Wi-Fi), over Bluetooth or by physical connection using a cable, for example through USB.
cell-tower connection - - phone/tablet - - - wifi - - other devices
router -- wifi - - phone/tablet