Pdh vs sdh describes difference between pdh and sdh

PDH SDH RELATED LINKS

Enthusiasts of PDH and SDH can also refer following pages on PDH as well as SDH terminologies. It covers difference between SONET vs SDH, SDH tutorial, PDH and SDH frame structure, SDH modulation, PDH over SONET and so on.

When compared with traditional SONET or SDH, the next generation of DWDM (Dense Wavelength Division Multiplexing) is seen as a simple architecture with high scalability, capacity add/drop, multiple ring terminations, multi-services, and multiple fabrics. Then, on comparison of SONET vs SDH vs DWDM, what are their differences exactly?