| 摘要 |
PROBLEM TO BE SOLVED: To provide a layer 2 tunneling protocol (L2TP) access concentrator (LAC) device or an L2TP network server (LNS) device capable of shortening a fail-over time of the LAC device or the LNS device in an L2TP, and a fail-over method.SOLUTION: When switching of an active system of a redundant control part is generated in the LAC device or the LNS device, a control message to be used for routine dead-or-alive confirmation is transmitted to the LNS device or the LAC device after the switching. In accordance with the presence/absence of a response from the LNS device or the LAC device, an L2TP tunnel for which recovery is required is selected and the number of L2TP tunnels to be recovered is decreased, thereby shortening the fail-over time.SELECTED DRAWING: Figure 5 |
