3. Conclusion

The first part of this dossier describes how Voice over IP has revolutionized existing architectures, thanks to a series of technological advances (and standards) that have enabled the implementation of conversational services based on packet switching on access networks such as ADSL, corporate LANs and UMTS mobile telephony. Three trends are outlined below.

• Trend towards a single "all-IP" network

  For companies that initially had two networks, one for transporting user data, and the other for telephony over circuit via a PABX, VoIP has facilitated the merging of these two networks into a single IP network supporting both user data and IP telephony. This merger has come at a price: the deployment of IP PBXs or VoIP platforms and IP telephones.

  As for the general public, who initially accessed...