Definition

The accelerated growth of content-rich applications that demand high bandwidth has changed the nature of information networks. High-speed communication is now an ordinary requirement throughout business, government, academic, and "work-at-home" environments. High-speed Internet access, telecommuting, and remote LAN access are three services that network access providers clearly must offer. These rapidly growing applications are placing a new level of demand on the telephone infrastructure, in particular, the local loop portion of the network (i.e., the local connection from the subscriber to the local central office). The local loop facility is provisioned with copper cabling,
which cannot easily support high bandwidth transmission. This environment is now being stressed by the demand for increasingly higher bandwidth capacities. Although this infrastructure could be replaced by a massive rollout of fiber technologies, the cost to do so is prohibitive in today's business models.

More importantly, the time to accomplish such a transition is unacceptable, because the market demand exists today!
This demand for data services has created a significant market opportunity for providers that are willing and able to invest in technologies that maximize the copper infrastructure. Both incumbent and competitive Local Exchange Carriers (ILECs and CLECs) are capitalizing on this opportunity by embracing such technologies. The mass deployment of high-speed Digital Subscriber Line (DSL) has changed the playing field for service providers. DSL, which encompasses several different technologies, essentially allows the extension of megabit bandwidth capacities from the service provider central office to the customer premises. Utilizing existing copper cabling, DSL is available at
very reasonable costs without the need for massive infrastructure replacement.

These new DSL solutions satisfy the business need to provision the network in a fast, cost-effective manner, while both preserving the infrastructure and allowing a planned migration into newer technologies. DSL has the proven ability to meet the customer demand for high bandwidth right now, at costs that make sense. ADSL, or Asymmetric DSL, has emerged as thetechnology of choice for delivering greater throughputto the desktop. Currently, the ADSL Lite specification,also known as g.lite, is expected to be standardized bythe end of June, 1999 as a low-cost, easy-to-installversion of ADSL specifically designed for the consumer marketplace. While g.lite is expected to become the
predominant standard for consumer services, HDSL2 is becoming the protocol of choice for business services
more on HDSL2 to come).

The Telecommunications Infrastructure

The telecommunications industry has developed and deployed cost-effective technologies and created global, high-bandwidth, interoffice networks capable of supporting the demands of the information age. This network infrastructure, however, has been lacking one significant component”a ubiquitous low-cost, high-bandwidth access circuit for the local loop. This fact, more than any other, has slowed the growth and availability of high-bandwidth network services. The pervasive copper cable infrastructure deployed throughout the local loop was historically incapable of supporting the throughput required by growing consumer traffic. In response, the industry embraced DSL, which has proven to be the most significant technological development for solving the local loop demand for higher bandwidth.