Voice over IP (VoIP) is a set of technologies that seeks to replace traditional analog voice services. There are three main compelling benefits to VoIP:
VoIP makes better use of network capacity. Traditional voice uses a 64-Kbps circuit, even when it is not active, but VoIP can use much less and no capacity when the line is not in use.
VoIP allows new and revolutionary features, such as the following:
Integration of voice and data systems (so that operators get customer information popped on to the screen when a phone call arrives).
Voice CODECs can improve sound quality (at the expense of bandwidth).
Integration with new clients. Instead of an analog phone, VoIP clients can include television boxes, Personal Digital ...