Patent ID: 8391287

Claim:
A packet relay method comprising: adding to a packet, when the packet having a multicast address or broadcast address set therein as a destination address is received from a source client, a common MPLS label which is an MPLS label common to destination clients corresponding to the multicast address or all destination clients corresponding to the broadcast address; and transferring the packet added with the common MPLS label over a ring network, wherein: the transferring further includes adding to the packet having the common MPLS label added, a Resilient Packet Ring (RPR) header in which a source address, a destination address, a unique address of a device executing the packet relay method for an allowable lifetime on the ring network of the transferred packet, the multicast address or broadcast address, and a predetermined allowable lifetime are set; the adding further includes acquiring an allowable lifetime corresponding to the common MPLS label added, from a table associating the allowable lifetime with the MPLS label common to destination clients corresponding to the multicast address or all destination clients corresponding to the broadcast address; and the table further includes first flag information indicating whether or not the packet added with the common MPLS label should be transferred from which direction of a device executing the packet relay method to the ring network, and second flag information indicating whether or not the transferring direction should be determined according to a hash function performed to at least one of the destination address and the unique address of the source client; and the transferring of the packet further includes acquiring from the table the first and the second flag information corresponding to the common MPLS label added, determining the transferring direction according to an arithmetic result of the hash function when the second flag information indicates that the transferring direction should be determined by the hash function while otherwise determining the transferring direction according to the first flag information.