Patent ID: 6950877
Filing Date: 2005-09-27
Classification: H04L

Abstract:
1. A packet transmission system comprising: at least one first host apparatus belonging to a first host group; at least one second host apparatus belonging to a second host group; and a router which transfers packets between said first at least one host apparatus and said second at least one host apparatus; each of said at least one first host apparatus in said first host group comprises, an insertion unit which inserts in a packet an IP address and a link-layer address of a destination host apparatus of the packet, where said destination host apparatus belongs to said second host group, and a first transmission unit which transmits said packet in which said IP address and said link-layer address are inserted; said router comprises, a plurality of ports each of which is connected to at least one host apparatus; a storage unit which stores a plurality of identifiers of said plurality of ports and a plurality of subnet addresses of a plurality of subnetworks at a predetermined level in a network hierarchy corresponding to the plurality of ports; a reception unit which receives a packet transmitted from a source host; a destination-IP-address extraction unit which extracts a destination IP address from said packet received by said reception unit; a subnet-address determination unit which determines one of said plurality of subnet addresses of said plurality of subnetworks to which said destination IP address extracted by said destination-IP-address extraction unit corresponds; a port determination unit which determines one of said plurality of ports corresponding to said one of said plurality of subnet addresses determined by said subnet-address determination unit, by referring to said storage unit, and a transmission unit which transmits said packet received by said reception unit, from said one of said plurality of ports determined by said port determination unit, while maintaining a same destination link-layer address as that in said received packet.