ABSTRACT
When the demand for long-distance data traffic arose, it was carried on the available telecommunication backbone, which was designed and optimized for voice traffic. This backbone was initially built over analog lines on copper pairs, coaxial cables, microwaves, etc. It initially migrated to the digital technology without any change in the media with PDH multiplexing and transmission. The backbone finally switched over to the SDH multiplexing with optical transmission of lasers on optical fiber cables. With the huge capacity of optical fibers, the advancement of technology and scales of economy with high demand, the cost of equipment continued to slide, which further boosted the demand. Data communications proved excellent in solving complex social problems; hence, a substantial demand for additional telecommunication traffic came from the data segment.
