120 Mbps plan has 100 Mbps download speed. When I asked the explanation on the phone, they said that "120 Mbps" is just the name of the plan and that they don't
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Unitymedia – Wikipedia
Unitymedia / Kabel BW: 2Play Plus mit 120MBit/s Highspeed-Internet nur 19,99 Euro pro Monat › Macerkopf
Neue Unitymedia Box -> Wlan deutlich schneller als Kabel? | ComputerBase Forum