Description: A threshold standard, which judges whether need to split a frame to several frames, gives an utmost length to the frame packet from the MAC layer. Once the length of a frame from MAC layer preponderates over the fragment threshold, it needs to split the frame to several splited frames. the units of the fragment threshold is byte, the range of the threshold is from 64 Bytes to 2346 Bytes, and the default fragment threshold is 2346 Bytes.