PATH SENSING METHOD, APPARATUS AND SYSTEM

This application provides a path awareness method, apparatus, and system, to accurately perform fault detection and fault positioning. The method includes: A source node sends, to a destination node, a first request packet that includes an identifier of a first node, an identifier of a first data flow, and first reserved information; receives a first response packet that includes the identifier of the first data flow, the identifier of the first node, and first indication information; and obtains, based on the first response packet, information indicating that a first path passes through the first node or a first path does not pass through the first node. The first request packet is used to request to determine whether the first path passes through the first node, the first reserved information is used to record a result about whether the first path passes through the first node, and the first indication information is obtained by recording, in the first reserved information, the result about whether the first path passes through the first node.