Patent ID: 6977885

Claim:
An apparatus for receiving a plurality of packets having the same contents sent from another apparatus through a plurality of physical lines that connect between the apparatus and the another apparatus, comprising: a line controller that controls packet flow over the plurality of physical lines; a plurality of mode flags, each mode flag associated with one of the plurality of physical lines, and for respectively storing either a primary or a secondary mode therein; a plurality of storage areas that store received packets; a plurality of line receivers receiving the plurality of packets having the same contents sent from the another apparatus through the plurality of physical lines; wherein at least one of the plurality of line receivers delivers received packets from one of the plurality of storage areas for forwarding if a mode flag corresponding to the at least one of the plurality of line receivers has a primary mode stored therein; a receiving line switching unit that monitors a presence of a failure of one of the plurality of physical lines corresponding to one of the plurality of mode flags storing a primary mode therein, and when a failure is detected, changes the one of the plurality of mode flags storing the primary mode therein to a secondary mode; and changes another of the plurality of mode flags storing the secondary mode therein to a primary mode; and thereupon compares each received packet stored in the received packet storage area corresponding to the mode flag changed to the secondary mode and each received packet stored in the received packet storage area corresponding to the mode flag changed to the primary mode; and receives a received packet equivalent to each packet lost due to the failure.