<p>A transmission apparatus (100) for monitoring a network, wherein a bypass path is made to reduce the load of the transmission apparatus. A maintenance information terminating part (30a) terminates maintenance information from an input frame constituted by a main signal and the maintenance information. A main signal processing part (20) processes the main signal extracted from the frame. A maintenance information producing part (30b) adds the maintenance information terminated by the maintenance information terminating part (30a) to the output signal of the main signal processing part (20) (the main signal).</p>
