Voice on IP: Internet, fixed and mobile

The third part of this dossier covers three areas of VoIP implementation. The first area concerns Internet telephony, for which manufacturers have come up with new products such as VoIP converter boxes, residential gateways (or "boxes") particularly for triple-play offers, and softphones for PCs such as Skype and Windows Live Messenger. The second area covers IP telephony, which introduces IP telephones widely deployed in large companies, IP PBXs and VoIP platforms replacing traditional PBXs, and Internet telephony gateways enabling long-distance calls at lower cost. Finally, the third area extends VoIP to cell phones, with softphones for cell phones such as Fring, Gizmo and Jajah, and mobile telephony over IP, where the mobile operator controls calls via the IMS domain of the UMTS network.

The examples of equipment and architectures are taken from public technical specifications for current industrial products, and are provided for illustrative purposes only.