METHOD AND APPARATUS FOR PATH DETECTION

This application discloses a path detection method and apparatus, applied to a scenario of forwarding at least two layers of labels. The method includes: generating, by a first network device, a first request packet used for path detection, where the first request packet includes a label stack and a TTL, and an initial quantity of layers of the label stack matches an initial value of the TTL; and sending the first request packet, where the first request packet is used to instruct a second network device to send a first response packet to the first network device when the TTL is 0 after being reduced by 1, and the first response packet reaches the first network device through an IP route. This avoids a case in which the first response packet continues to follow a TTL timeout procedure, thereby reducing a link detection delay and improving detection accuracy.