This tutorial covers the SDH (Synchronous Digital Hierarchy) frame structure, explaining the STS-1 (Synchronous Transport Signal-1) SONET/SDH frame in detail. At low transmission rates, data can also be. This tutorial provides an overview of SDH/SONET, covering basics, HDLC framing, terminologies, rates, and the SONET STS-1 SDH Frame. There are no specific prerequisites for this document. This document is not restricted to specific software and hardware versions. Refer to Cisco Technical Tips Conventions for more information on. The STM-1 frame is the basic transmission format for SDH. The STM-1 frame consists of overhead plus a virtual container capacity (see Figure 1). Why did SDH emerge? ---- Need for a system to process increasing amounts of information.
