Which of the following statements about SONET/SDH is FALSE?

The statement regarding SDH primarily being used in North America is indeed false. SONET (Synchronous Optical Network) is widely adopted in North America and has been standardized by ANSI, while SDH (Synchronous Digital Hierarchy) is the counterpart of SONET developed for use internationally, primarily in Europe.

This distinction highlights the different regions where each technology is most prevalently implemented. SONET serves as the North American standard, while SDH is more prevalent globally. Consequently, the assertion that SDH is primarily used in North America misrepresents the application of these technologies.

The other statements accurately reflect the characteristics of SONET/SDH. SONET/SDH is indeed a Layer-1 (physical layer) technology, which focuses on the transmission of digital signals over fiber optics. The fundamental structure of SONET is represented by the STS-1 frame, which serves as the basic building block for bandwidth and network capacity. Moreover, an STS-1 frame is designed to be exactly one third of an STM-1 frame, as STM-1 is the SDH equivalent and allows for efficient cross-system interoperability and scaling.