Patent ID: 7869428

Claim:
A packet transfer method in a network apparatus that transfers packets, comprising: generating, using a sending side apparatus, two packets, the packets being copies of a send packet, and including a first packet and a second packet; providing, using the sending side apparatus, a sequence number identifying a same sending sequence to each of the packets, the sequence number including a first sequence number and a second sequence number, the first packet having the first sequence number, and the second packet having the second sequence number; providing, using the sending side apparatus, a first identifier corresponding to a first send/receive pair and a second identifier corresponding to a second send/receive pair, to a respective one of the packets in order to send the packets over two routes, in the sending side apparatus, which are different from each other; and receiving, using a receiving side apparatus, the packets via two receiving units; recognizing the first and second identifiers, each of the first and second identifiers corresponding to one of the first and second send/receive pairs; identifying packets having a same information and the sequence based on the sequence number when the first and second identifiers are the same; selecting the 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 the first sequence number of the first packet being equal to a reference counter number; selecting the 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 the 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.