Patent ID: 8625588

Claim:
A packet transfer method performed by packet transfer apparatuses provided in a packet sending side and a receiving side in a communication network for transferring a packet by determining a transfer destination by referring to destination information of the packet, comprising: setting, two or more independent routes between the sending side packet transfer apparatus and the receiving side packet transfer apparatus; at the sending side packet transfer apparatus: inserting, information identifying a sequence of a packet into a part of the packet that is not a header portion referred to for determining the transfer destination of the packet; copying the packet to generate two or more packets; and sending the packets at substantially a same time over the independent routes respectively; at the receiving side packet transfer apparatus: receiving each packet from the independent routes; identifying packets having the same information and the sequence based on the information identifying the sequence for each packet; selecting a first packet of one of the packets of a same sequence so as to send the selected one of the packets downstream, in response to a first sequence number of the first packet being equal to a reference counter number; selecting a second packet of one of the packets of the same sequence so as to send the selected one of the packets downstream, in response to a second sequence number of the second packet being equal to the reference counter number when the first sequence number of the first packet is greater than the reference counter number; and discarding a remaining one of the packets which is not selected by the selecting, wherein, when only one of the packets of the same sequence is received by the receiving, only the received one of the packets is sent downstream.