This Recommendation specifies the transmission of MPEG-2 transport streams within SDH networks working at the G.707 hierarchical bit rate of 155 520 kbit/s or at a bit rate of 51 840 kbit/s. The use of any of these bit rates is optional, if however one or more rates are selected the complete specification applies. The definition of the network aspects of the transmission of MPEG-2 transport streams is based to the maximum extent on existing international standards. The equipment considered in this Recommendation is the Network Adapter performing the adaptation between MPEG-2 transport streams and the interfaces of SDH networks. The bit rates and the frames structures for STM-N signals, the SDH multiplexing structures and the different overheads of an STM-N frame (POH, SOH) are specified in Recommendation G.707. The application of this Recommendation is restricted to a physical layer point-to-point connection without ATM connection fünctionality at intermediate points.