U-PTR is an indicator used to indicate the position of the information net load in the STM-N frame, so that the receiving end can correctly separate the information net load according to the value…

U-PTR is an indicator used to indicate the position of the information net load in the STM-N frame, so that the receiving end can correctly separate the information net load according to the value of this position indicator (pointer value). Therefore, as long as the pointer points to the information net load area, the receiving end can correctly separate the service signal.