ices and an exponen- tial service duration, the gain related to SR DBA is something between 2 and 4. This means that if the ONU is sufficiently equipped to manage this situation, the per- ceived capacity evaluated is around 600MHz. However, this perceived bandwidth is related to the low activity bundle, and is not use- ful. Generally, carriers are more interested in the possibility of accommodating the VoD without changing the GPON hardware. Frequently, in front of a market forecasts for the fruition of new services, the carrier is interested in evaluating the maximum possible penetrations of the VoD before the need of increasing the physical access capacity arises. Since this type of evaluation is quite instructive, we will follow it in certain detail, expos- ing an evaluation that a tier one carrier has shown at a conference in the framework of a discussion on the GPON capacity to face the pace of fast traffic growth [14]. The calculation refers to a typical urban area served by a central office. In the area, there are 400 users divided into three classes: 1. Thirty percent of the users (120 units) have only telephone service; this means that they have an IP phone; the average traffic produced by such users is 30 mErlang per customer. 2. Thirty percent of the customers (120 units) have the same telephone service con- sidered above, plus a fast Internet browsing service with a peak guaranteed band- width of Mbit/s. 3. Forty percent of the users (160 subscribers), on top of the service characteristics of the second class, have IP-TV service. The New Access Network Systems and Enabling Technologies The different services are implemented SO that the IP phone is coded for a peak bandwidth of 26 kbit/s while the IpTv is coded, both for the standard and the high definition channels, within a bandwidth of 16Mbit/s. This is a conservative hypothesis, mainly assumed to simplify the calculation. However, almost nothing changes with a more accurate modeling of the IpTv bandwidth. Finally, it is assumed that in the peak hou