Abstract: A method of transporting a packet oriented client signal which uses a buffer-to-buffer flow control mechanism over a synchronous transmission network by assigning an arbitrary synchronous payload, where the synchronous payload bandwidth may be significantly smaller than the full bandwidth of the client signal. Flow control over the synchronous network is provided by the buffer-to-buffer flow control mechanism of the client signal to automatically regulate the data throughput to ensure no data can be lost. The method is independent of the Client Signal Data Rate and the provisioned SDH/SONET bandwidth, and SDH/SONET payload which may be non-concatenated, contiguously concatenated, or virtually concatenated. In particular, the method may be used to support the transport of Fibre Channel (1G, 2G and 4G), and ESCON (200M) in a synchronous payload.