Patent ID: 7839772

Claim:
A network device, comprising: a first input port to receive a first data signal, via a first working route between two terminals, and to selectively forward the first data signal towards a switching fabric; a first framer, implemented at the first input port, to assemble the first data signal into one or more frames, and to use a first determination function to determine whether to forward the first data signal to the switching fabric, when the first data signal is being received normally via the first working route, or to cut-off forwarding of the first data signal to the switching fabric when the first data signal is being received abnormally via the first working route; a second input port to receive a second data signal, via a first backup route between the two terminals, and to selectively forward the second data signal towards the switching fabric; and a second framer, implemented at the second input port, to assemble the second data signal into one or more frames, and to use a second determination function to determine whether to forward the second data signal to the switching fabric, when the first data signal is being received abnormally via the first working route, or to cut-off forwarding of the second data signal to the switching fabric when the first data signal is being received normally via the first working route, where the second input port is different from the first input port.