Introduction
Frame Check Sequence
The judgment process is as follows: the sending network card uses a polynomial calculation, called cyclic redundancy check (CRC), and writes the calculation result In the FCS field, the receiver receives this frame and performs the same CRC calculation on it. If the calculation result is the same as the received FCS field, there is no error in the frame. If they are different, the receiver believes that an error must have occurred in the frame and discards the frame.
Identification method
The identification method of the frame check sequence in the general frame processing encapsulation mode, the method includes: stripping the CoreHeader field of the GFP frame in the received GFP data stream, For the stripped GFP data stream, a delimitation signal is generated indicating whether the frame head, end of the frame and the frame data are valid, and the delimitation of the GFP frame is completed; according to the delimitation signal, the PFI information in the GFP frame is extracted, and the GFP frame is stripped According to the PFI information, determine whether the FCS field is included in the GFP frame. If it is included, determine the starting position of the FCS field and strip the FCS field; otherwise, skip this process. The invention also discloses a device for identifying the frame check sequence in the universal frame processing encapsulation mode. The method and device of the present invention can completely reduce the bit error rate, have strong adaptability, and enable the equipment to be flexibly used in various occasions.
Features
The device for identifying the frame check sequence in the general frame processing (GFP) encapsulation mode is characterized in that the device includes: a frame delimiting module, frame header identification and Stripping module and FCS stripping module. Among them, the frame delimitation module is used to receive GFP data stream, strip the CoreHeader field of GFP frame, and generate delimitation signals indicating whether the frame header, end of frame and frame data are valid. The output is accompanied by delimitation. The GFP data stream in the CoreHeader field is removed to the frame header recognition and stripping module; the frame header recognition and stripping module is used to strip the dead load header of the GFP frame, and whether the GFP frame contains the FCS field is generated according to the sop signal in the delimitation signal PFI indicator signal, output the GFP data stream accompanied by the PFI indicator signal and delimitation signal and the dead load head has been stripped to the FCS stripping module; the FCS stripping module determines the position of the FCS domain according to the PFI indicator signal and the delimiting signal, and strips the FCS Domain.