The present invention relates to a field of communication technology, and more particularly to a communication system, a label switched router, a network device, a method for handing over a route, and a method for notifying a state of advertising a label so as to improve an accuracy occasion for handing over a route. A liberal LSP between an upstream LSR and a downstream LSR is established; it is confirmed that establishing the liberal LSP is accomplished; a handover notification is sent to the upstream LSR; and the upstream LSR hands over the route according to the handover notification. By adopting such technical solution, the accuracy occasion for handing over the route is improved so as to avoid label forwarding interruption, and reduce the influences on the convergence time of handing over the route.