Method for high speed search tables switching and packet forwarding apparatus

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 present invention provides a packet forwarding apparatus that accommodates two output ports. The packet forwarding apparatus is embodied in a structure having an element for storing the output information about each of a plurality of pieces of input header information, an element for storing the output information about an output port that is associated with input header information and used as a bypass in the event of a fault, and an output information address rewrite processor for writing, in the event of an output port failure, the output information address associated with an output port that should serve as a bypass.