Handovers can exist on a higher level as well. 10 years ago there were calling apps that could handover a WiFi VoIP call to the gsm network (not using voip but

Handovers can exist on a higher level as well. 10 years ago there were calling apps that could handover a WiFi VoIP call to the gsm network (not using voip but actual gsm) when the WiFi goes bad and later switch the same call back to WiFi.