The present invention is directed to rapidly replacing an output destination port with a bypass port and replacing packet output header information with bypass header information when a port accommodated by a router within an IP or MPLS network becomes faulty. The planar illuminator has a reflection surface, on which minute concavo-convex shapes are substantially randomly formed. In addition, the user interface may further display a plurality of vertical lines and a plurality of horizontal lines arranged in a grid-like pattern and placed over the sonographic image.