Employees move around. Forty percent of conference calls originate on a mobile instrument. Other calls that begin on a desk phone often go mobile partway through, as participants move from one location to the next. A collaboration call, say with slide-sharing or a video conference, may originate on a 4G wireless network. As the worker travels so does the call, maybe to 3G or 2G. The call is quite likely to be dropped on wireless network handoffs.