VoIP technology, a packet-switching technique, uses the Internet to provide phone service and has several advantages over circuit switching.
Packet switching allows several telephone calls to occupy the same amount of space that would take up only one phone call on a circuit-switched network. Using the PSTN (public switched telephone network), a 10-minute phone call uses 10 full minutes of transmission time at a cost of 128 kbps.
A 10-minute call using VoIP may occupy only 3.5 minutes of transmission time at a cost of 64 kbps. So, those 3.5 minutes leave the other 64 kbps free. In addition, during the 6.5 minutes of silence included in a 10-minute conversation, the 128 kbps capacity can be used in other ways.
Another three or four calls could easily fit into the space used by a single phone call using circuit switching. Data compression would further reduce the size of each call.