Control method for access gateway and communication system

Abstract

In order to provide a redundancy configuration to an access gateway apparatus in which a control plane and a user plane are separated, the access gateway apparatus includes: a control computer for receiving control signals from the networks to establish the communication path, thereby determining packet transfer information for the data; and a transfer computer for receiving the packet transfer information from the control computer to transfer the data through the communication path. The transfer computer includes: a plurality of first transfer computers for executing the transfer of the data; and a second transfer computer for taking over, when a fault occurs in any one of the plurality of first transfer computers. The control computer includes: a first control computer for processing the control signals received from the networks; and a second control computer for taking over, when a fault occurs in the first control computer.

1 . (canceled) 
     
     
         2 . An access gateway apparatus comprising:
 a plurality of control access gateways, including a first control access gateway and a second control access gateway, for determining a transfer path for data between a network including terminals and base stations and a core network, the second control access gateway being configured to take over processing of the first control access gateway when a fault occurs in the first control access gateway; and   a plurality of transfer access gateways, including a plurality of first transfer access gateways and at least one second access gateway, for transferring data between the network and the core network via the transfer path, the at least one second access gateway being configured to take over processing of one of the first transfer access gateways when a fault occurs in said one of the first transfer access gateways;   wherein the first control access gateway is configured to store, for each of the plurality of first transfer access gateways, session information including the transfer path;   wherein the first control access gateway is configured to send, when a fault occurs in one of the plurality of first transfer access gateways, session information for the faulty first transfer access gateway to one of the at least one second transfer access gateway;   wherein the at least one second transfer access gateway is configured to take over processing of the faulty first access gateway based on the session information received from the first control access gateway;   wherein the second control access gateway is configured to receive the session information from the first control access gateway in a predetermined cycle; and   wherein the second control access gateway is configured to take over, when a fault occurs in the first control access gateway, the processing of the first control access gateway based on the received session information.   
     
     
         3 . An access gateway apparatus according to  claim 2 , wherein the at least one second transfer access gateway comprises a plurality of second transfer access gateways. 
     
     
         4 . An access gateway apparatus according to  claim 2 ,
 wherein the first control access gateway is configured to store session information on ongoing communication as active session information and session information on suspended communication as idle session information;   wherein the first control access gateway is configured to obtain an identifier, an address, and active session information for the faulty first transfer access gateway to transfer the obtained identifier, address, and active session information to one of the at least one second transfer access gateway; and   wherein the first control access gateway is configured to, after the second transfer access gateway takes over transferring data, send the idle session information set to the faulty first transfer access gateway to the second transfer access gateway.   
     
     
         5 . An access gateway apparatus according to  claim 2 ,
 wherein the first control access gateway is configured to transfer data based on the session information set to the faulty first transfer access gateway and, after starting transferring data, send the identifier, the address, and the session information for the faulty first transfer access gateway to the second transfer access gateway; and   wherein the first control access gateway is configured to, after the second transfer access gateway takes over the processing of the faulty first transfer access gateway, stop the transferring data.