Transmission path fault processing method and apparatus, and system

A network device operating as a first network device, comprising:

• a communications interface;
• a processor;
• and
• a memory;
• wherein the memory is configured to store a software program, which, when executed by the processor, causes the processor to perform operations, the operations comprising:
• receiving, at the communication interface, a stitching label and a stitching label stack list corresponding to the stitching label that are sent by a stitching network device,
• determining, in a process of sending a packet through a primary path, that the stitching network device is faulty, the packet comprising a label stack list used to guide packet forwarding on the primary path, and the stitching network device being a next-hop network device of the first network device on the primary path, and
• replacing, the stitching label in the label stack list with the stitching label stack list, and switch, based on the updated label stack list, the packet to a backup path for sending.

A network device, comprising:

• a communications interface;
• a processor;
• and
• a memory;
• wherein the memory is configured to store a software program, which, when executed by the processor, causes the processor to perform operations, the operations comprising:
• receiving, at the communication interface, a stitching label and a stitching label stack list corresponding to the stitching label that are sent by a controller, and
• flooding, by the network device to another network device on a network, the stitching label and the stitching label stack list corresponding to the stitching label.