| 摘要 |
<p>PURPOSE:To highly reliably control a line concentration node by providing a communication line for the supervisory information communication of a concentration node housed in a packet switching network to the plural packet switching networks and providing respective permanent virtual circuits. CONSTITUTION:For the permanent virtual circuit(PVC) for the control information communication spread with the use of plural packet exchange networks 1a and 1b between a control node 20 and a line concentration node 30, an abnormal condition and an communication interrupted condition are recognized at every supervisory node and concentration node by respective PVC supervisory functions held by the control node 20 and each line concentration node 30 and a cyclic boring and response supervisory functions held by the control node 20. Further, by using the PVC of the other normal network, the control communication is maintained without interrupting the communication at any time. Thus, the node can be highly reliably controlled.</p> |
