Introduction of new technologies in the French transmission networks

A strategy studied by France Telecom for introducing synchronous digital hierarchy (SDH) to structure its transmission network is discussed. The respective merits of SDH and asynchronous transport mode (ATM) technologies are examined, and a broad description of the present transmission network of France Telecom is given. Strategies for deploying SDH equipment such as synchronous transport module-N line systems, add-drop multiplexers, and administrative unit or virtual container crossconnect equipment in the network are described. The need for a smooth evolutionary path from the existing network is emphasized, as well as the prime importance of a synergy with telecommunications management network development to take full advantage of the potential management capabilities of SDH equipment. The possibility of early introduction of ATM to provide professional services such as local area network interconnection on a nationwide basis, without any constraint on or from the rate of evolution of the physical network, is considered.< >