For Telecom Italia, the explosive growth in demand for IPv4 addresses is somewhat analogous to the explosive growth in second phone lines, direct dial-in lines, and fax machines in the 1980s, when the demand for telephone numbers exceeded the available number ranges. Their challenges are to overcome IPv4 address exhaustion, add new subscribers to the network and migrate to IPv6 while supporting IPv4 devices. They chose Juniper Networks to overcome these challenges. They have implemented Juniper Networks DS-Lite, MX Series 3D universal edge routers and Multi-Services Dense Port Concentrator (MS-DPC). The results of implementing Juniper Networks were handle IPv4 address exhaustion incrementally by using IPv6 as a transport layer for IPv4 in the access network and it support both IPv4 and IPv6 devices.