ABSTRACT
Some of the flavors of xdsl technology have been around for awhile but sold under a different label. However, for the most part, end users just do not care what it is called, so long as it provides more bandwidth at less cost than before. Currently, Digital Subscriber Line (DSL) technology comes in several popular flavors: asymmetrical DSL, high bit rate DSL, symmetric DSL, or very high speed DSL. In the proper setting, xDSL is capable of supporting any specific user bandwidth requirement given the local availability of copper. This is fine as long as one is the local exchange carrier, and one owns the copper. xDSL technology is potentially a lower-cost replacement for dedicated 56Kbps local loops used to tie into a Frame Relay service. The original Digital Subscriber Line service was introduced as ISDN in the 1980s. This technology compressed 160Kbps into an 80KHz bandwidth of the local loop.
