For alignment; Indicates the starting position of VC-n in the corresponding AU or TU frame.

For alignment; Indicates the starting position of VC-n in the corresponding AU or TU frame. • This way: The receiver can correctly remove the corresponding VC from STM-N, and then The VC and C packages are separated into separate low-rate signals, such as PDH, which means that the low-rate path signal can be dropped directly from the STM-N signal.