A highly developed information society requires communication networks to support diverse telecommunications services. The volume of information transmitted, exchanged, and processed through communication networks will continue to increase, which requires modern communication networks to develop in the directions of digitalization, integration, intelligence, and personalization.
The transmission system is an important component of the communication network. The quality of the transmission system directly affects the service quality of the communication network. In order to expand transmission capacity and improve transmission efficiency, in digital communications, several low-speed digital signals are often combined into a high-speed digital signal through digital multiplexing. Digital multiplexing must be carried out according to certain standards. The International Telecommunication Union Telecommunication Standardization Sector (ITU-T), formerly the International Telegraph and Telephone Consultative Committee (CCITT), has specified two basic multiplexing standards: the Plesiochronous Digital Hierarchy (PDH) and the Synchronous Digital Hierarchy (SDH). China adopted the PDH multiplexing method before 1995. After 1995, with the rapid development of optical fiber communications, the SDH multiplexing method was introduced, and the existing PDH digital transmission networks can be gradually incorporated into SDH transmission networks.
Related knowledge expansion
PDH frame structure and main defects
SDH generation and characteristics
SDH definition and basic equipment types
Section overhead functions Basic concepts of mapping and multiplexing
SDH mapping and multiplexing units Methods for mapping and multiplexing common
PDH tributary signals into
STM-1 Multiplexing of N AUGs into
STM-N Path overhead
AU-4 pointer
TU-3 pointer
TU-12 pointer
Development history of SDH-based MSTP
MSTP concept and its functional model
Transmission implementation of Ethernet services on MSTP
MSTP support for 3G
