Why the DSL subscriber base is growing faster than any other broadband technology
posted by Marc Goldburg
April 12th, 2010
Broadband access has become a necessity in developing and developed economies alike. Some countries, such as Finland, have gone so far as to make access to broadband a fundamental human right. The debate over the value and necessity of broadband is over. Commercial, technical, and policy debates have now shifted to the best processes for making broadband universally available. There's no shortage of topics to be debated: how will universal broadband be funded? how will it be leveraged for society's good? who will deliver it? what technologies are appropriate? how will competition in broadband delivery be fostered? and so forth. The goal for this blog is to address these larger broadband industry issues. We invite you to browse the other portions of our Web site for specific information on ASSIA's products.
For this inaugural blog, let's focus on why DSL continues to serve more subscribers than any other broadband technology, and why the DSL subscriber base is growing faster than for any other broadband technology. The reasons are simple: economics and performance. DSL is the most cost-effective, high density, wide-area broadband delivery method for broadband providers with access to copper. VDSL2 provides speeds of 25-50 Mbps over copper loops in excess of 1 km, and the next generation of VDSL, so-called, "vectored VDSL," will provide speeds of up to 100 Mbps over that same copper plant. Over longer loops of up to 10 km, ADSL technology provides speeds of up to 24 Mbps. Further, these DSL speeds are "dedicated" per-subscriber speeds. For other broadband technologies, the quoted peak speeds are often the maximum aggregate throughput shared among subscribers on a fiber, cable or wireless link. For example, the new cable standard, DOCSIS 3.0, provides at least 155 Mbps of downstream speed, but if 10 users on that cable are simultaneously downloading data, the peak speed seen by any subscriber may only be a tenth of that 155 Mbps, or 15.5 Mbps. (PointTopic is an excellent source of free quarterly statistics for broadband usage)
That's not to say that continued, but relatively modest investment in the copper plant isn't necessary to provide competitive broadband over DSL. Shortening the copper loops to around 1 km in length helps to realize speeds above 20 Mbps. This is typically accomplished by moving DSL access devices (a DSLAM, the equipment at the other end of the subscriber's copper loop) to cabinets in the subscribers' neighborhoods or in the basements of their apartment buildings. These DSLAMs are in turn connected to the DSL providers' core networks via fiber. While this incurs cost, it is far less than the $1,500 or more typically required to connect each subscriber in fiber-to-the-home (FTTH) deployments. Automated management of DSL networks―ASSIA's core area of interest―is another critical area where small investments per subscriber lead to huge returns in increased performance and in decreased operations costs.
ASSIA's technology and products have been purchased for more than 80% of the DSL lines in the United States, and many millions of lines in Europe and Asia, which is the strongest possible testament to the value of automated DSL network management.