Patent ID: 8437248

Claim:
A method for a network device to access a packet switched network, wherein the method is applied to a system in which the network device accesses the packet switched network by connecting to Provider Edge Routers (PEs) in an active-standby mode, and the method comprises: sending, by an active PE a fault detection message to the network device through the active PE's interface connected to the network device; sending, by a standby PE a fault detection message to the network device through the standby PE's interface connected to the network device; returning, by the network device, a fault detection response to the active PE if determining that the fault detection message sent by the active PE is received through an active port of the network device within a preset period; or changing, by the network device, a standby port of the network device corresponding to the active port over to the active port if determining that the fault detection message sent by the active PE is not received through the active port within the preset period, receiving the fault detection message sent by the standby PE through the active port after failover, and returning a fault detection response to the standby PE through the active port after the failover; setting, by the active PE, a state of the active PE's interface connected to the network device to “up” and advertising a first route to a remote PE if determining that the fault detection response is received through the active PE's interface connected to the network device within the preset period; setting the state of the active PE's interface connected to the network device to “down”, and withdrawing the first route advertised to the remote PE if determining that the fault detection response is not received through the active PE's interface connected to the network device within the preset period; and setting, by the standby PE, the state of the standby PE's interface to “up” and advertising a second route to the remote PE after receiving the fault detection response through the standby PE's interface connected to the network device.