Patent ID: 7440414
Filing Date: 2008-10-21
Classification: H04L

Abstract:
1. A communication relay device with a redundant line function enabling a line to be connected as a redundant channel, wherein the relay device configures the redundant channel from among a plurality of lines in a network in accordance with a wide area network environment, the relay device comprising: first and second ports which are each connected to one end of a respective line of the plurality of lines, and wherein another end of each respective line of the plurality of lines is connected to a port of another communication relay device; a closed port setting section which sets one of the first and second ports as a closed port, thereby configuring the network to be free of a loop; a closed port setting information notifying section which notifies a device connected to the closed port, via the closed port, of closed port setting notification information thereby notifying the connected device that the port to which the device is connected is set as the closed port, wherein the connected device has a same structure as the communication relay device; and a datagram transmission stopping section which, in the connected device, upon receiving the closed port setting notification information via one of the first and second ports of the connected device, stops transmission of a datagram from the port via which the closed port setting notification information is received.