NETWORK SYSTEM, SWITCHING METHOD OF GATEWAY DEVICE, FIRST TUNNEL TERMINATION GATEWAY DEVICE AND SECOND TUNNEL TERMINATION GATEWAY DEVICE

摘要

PROBLEM TO BE SOLVED: To stably resume service when the main system GW is restored from fault, and to achieve a short service interruption time in a network system using a tunneling protocol by installing the main system GW and a standby system GW in long distance.;SOLUTION: The main system GW1 and the standby system GW2 transmit and receive a heartbeat packet which can arrive at a network having a different prefix of IP address, and synchronize the IPsec information as required. When there is a fault on the line linked to the main system GW1, the main system GW1 is brought into a standby state (route deletion) and a heartbeat packet provided with a low priority is transmitted from the main system GW1 to the standby system GW2 thus bringing the standby system GW2 into an active state (route advertisement).;COPYRIGHT: (C)2011,JPO&INPIT