The majority of the time, an Internet connection is too sluggish and lacks sufficient capacity for a VoIP HD audio conversation. You may also be suffering high packet loss if your connection is shaky. Worse, both of these problems are typically exacerbated while you're on the road. Mobile devices are unable to switch between multiple Wi-Fi networks or mobile towers in a smooth manner. Apps like WhatsApp will hang, lose Internet VoIP calls, and potentially stop working if this happens.