A review of Plesiochronous Digital Hierarchy (PDH) and Synchronous Digital Hierarchy (SDH)

TL;DR

This paper compares Plesiochronous Digital Hierarchy (PDH) and Synchronous Digital Hierarchy (SDH), highlighting their features, differences, and the reasons SDH replaced PDH in modern telecommunications networks.

Contribution

It provides a comprehensive review of PDH and SDH technologies, explaining their features and the issues leading to SDH's adoption over PDH.

Findings

SDH offers greater flexibility and interoperability than PDH.

SDH provides higher data transmission efficiency and scalability.

PDH's limitations prompted the development of SDH standards.

Abstract

With the advancement in telecommunications, packet traffic is rapidly becoming the mainstream of data traffic. The use and deployment of Synchronous Digital Hierarchy (SDH) networks for interconnection has gained traction worldwide due to its flexibility and standard for interconnecting multiple vendors, low operating cost and the high quality of service it provides. Plesiochronous Digital Hierarchy (PDH) on the other hand has been used before the introduction of the SDH standard and it also provides a means to transport large quantity of data via digital equipment such as radio wave systems, optic fibre and microwaves. In this paper, we shall discuss both PDH and SDH technologies and identify some of the features of both and the issues in PDH that brought about the introduction of the SDH technology.