Switching method and apparatus for main and standby devices

The present invention relates to a switching method and apparatus for main and standby devices. The switching method for main and standby devices comprises: when an access device uses a main device to access a network, detecting an interface on the main device directly connected to the access device or a transmission device, so as to determine whether a link from the access device to the main device has a fault or not; and when it is determined that the link from the access device to the main device has a fault, notifying a redundancy group having a routing function to switch the main device and a standby device, so that the access device uses the standby device before switching to access the network.