Patent ID: 7499396
Filing Date: 2009-03-03
Classification: H04L

Abstract:
1. A router selecting method in a local area network (LAN) which includes plural routers, at least one of the plural routers performs relaying with an external network, the router selecting method comprising: a step of periodically multicasting, by each of the routers in a common segment of the local area network, a multicast packet including an identifier of the respective one of the routers; a router selecting step of selecting, by, a destination to forward a data packet among other routers in the common segment, based on information included in the multicast packets received from the other routers in the common segment; a step of determining, by each of the routers, in accordance with conditions determined in advance whether to relay the data packet, received from a node or a one of the routers in the common segment, to another segment; a forwarding step of, if the one of the routers which has received the data packet does not relay the data packet to the other segment, performing, by the one of the routers, a redirection by: (1) specifying the selected one of the routers as the relay destination to a source node or router which originally sent the data packet and (2) one of: (i) forwarding the data packet to the specified one of the routers or (ii) discarding the data packet and (3) transmitting a redirection packet to the source node; and a step of transmitting, by the source node which has received the redirection packet, the data packet and subsequent data packets to the specified one of the routers based on information in the redirection packet, wherein the forwarding step is repeated until the data packet is received by the one of the routers which performs relaying of the data packet to the other segment or to the external network.