Change the tires tomorrow, all four. Although it is a necessary expense, it is still hidden in my heart, which means changing tires tomorrow and changing all four. Although it is a necessary expense, it still hurts.
Communication field. The function of overhead is to provide detailed monitoring and management functions for SDH signals. The classification of monitoring can be divided into segment-level monitoring and channel-level monitoring. In the process of network transmission, due to the transmission of signals, it is necessary to change the data format, and it is inevitable to add some redundant data, which is necessary for transmission. The proportion of these redundant data in the source data is called overhead.