According to the same studies, broadband penetration will rise to 75% by 2010, while at the same time, 10 to 20% of U.S. households will have subscribed to the highest access speeds. This data reflects the general tendency toward an increasing demand for more bandwidth, keeping pace with increasing computing power and memory/storage capacity.
The growing demand for higher speed broadband access connections is definitely connected to the emergence of high-quality bandwidth-consuming services such as massive-scale IP video transmission or multipoint video-conference. Examining the trends in the European market, Seals (2006) claims that it is evident that an increasing number of network access providers have already launched or plan to launch TV services over their respective IP networks (IPTV service). It is estimated that 40% of households in the U.S and Europe will have access to IPTV by 2010, while as much as 20% will have access to High-Definition IP-TV (HDTV quality video). To meet the inflated bandwidth needs at the network access, standard residential connections should be able to offer between 20 to 30Mbps in the downstream direction, which translates into supporting two HDTV compressed streams concurrently or a range of standard-definition channels, together with high-speed Internet access and voice over IP (VoIP).
At the present time, ADSL is the most widely deployed DSL flavor in the world. It is however incapable of supporting the necessary speeds for offering IPTV and HDTV services, as it can only offer up to 8Mbps broadband connectivity, subject to subscriber loop conditions. A newly proposed standard, the ADSL2+ technology, providing greater reach, higher bit rates, and added quality of service facilities, is now emerging as a possible solution, as new equipment implementing this ITU standard is being deployed in commercial networks. Furthermore, the ADSL2+ technology also implements the reach extension model (ITU-T G.992.3 Annex L, 2002), as well as the increased upstream option (ITU-T G.992.3 Annex J, 2002), referred to as ADSL2+ Annex J/M (ITU-T G.992.5 Annex J/M, 2003). Thus, the main advantages of the new technology are its potential for greater reach and higher speed. The increased rates enable the so-called triple-play service concept, consisting of converged Internet-access, telephone, and TV/VoD services over a standard telephone line. In this context, access rate offerings above the standard ADSL range of 3-6 Mbps downstream are gradually becoming available, while in certain countries access rates above 20 Mbps are already becoming the norm.
The greater reach allows more customers to enjoy such services over their local loop. However, just as in the case of standard ADSL, the actually achievable rate is subject to the condition of the subscriber loop
