Abstract: A relay apparatus includes: a receiver to receive a control message including a communication traffic amount of data sent from a first node on a first side; a total communication traffic amount notifying unit to calculate a total of communication traffic amounts included in a control message for each the first node and to notify a second node on a second side of a calculated total communication traffic amount; and an upper-limit communication traffic amount notifying unit to distribute a first upper-limit communication traffic amount of a line coupled to the second node or a second upper-limit communication traffic amount supplied from the second node in accordance with a proportion of a communication traffic amount included in the control message so as to determine a third upper-limit communication traffic amount of data transfer at the first node, and to notify the first node of the third upper-limit communication traffic amount.

Abstract: A communication apparatus communicably connects a network of a plurality of apparatuses and a data relay apparatus to another network of the same manner as that of the network by detecting a failure occurring in the network, and determining a detour to assure communication between an apparatus connected to a network disconnected due to the failure detected and the other network. A tunneling is established serving as a virtual direct communication circuit to the determined detour.

Abstract: A communication apparatus communicably connects a network of a plurality of apparatuses and a data relay apparatus to another network of the same manner as that of the network by detecting a failure occurring in the network, and determining a detour to assure communication between an apparatus connected to a network disconnected due to the failure detected and the other network. A tunneling is established serving as a virtual direct communication circuit to the determined detour.