Data frames are converted to a format suitable for transparent, flexible concatenated transport such that a network element not supporting flexible concatenation may transparently pass the data frames. Flexible concatenation involves nonstandard data frames such as an STS-4c or an STS-Nc in which the time slots do not occupy rigidly defined contiguous time slots. In transparent flexible concatenation, the pointer from the parent time slot is used for each of the child time slots and the concatenation identifier is set to indicate no concatenation. In this way, the concatenated data appears to be a series of conventional STS-1s such that pointer processing may be successfully accomplished even by a network element not capable of handling non-standard concatenations. A downstream receive framer reconstructs the original STS-Nc based on the N STS-1s and a concatenation table the contents of which are shared between the transmit framer and the downstream receive framer.