At present, a fiber optic network used a lot. So the quality of fiber optic network. So it is very important whether the transmission media such as fibre-optic (Fiber optic) currently use only type single mode (Single Mode) with a fibre-optic type multiple modes (Multi Mode) but not used, and the other one is a problem. When a fiber optic network unavailable (Link Down) caused the router (Router) work hard because set various functions into the router status of too much load device. Result in the router is broken or work efficiency of the system decreased.