Method and device for long-term storage of cross-domain path information

The present invention relates to a method and device for long-term storage of cross-domain path information. The method is for use on a stateless PCE and comprises: a first PCE computes a path; a first node in the path transmits to the first PCE query information for querying first intra-domain path information corresponding to a first PATH-KEY, generates, on the basis of a query result returned by the first PCE, and saves a third PATH-KEY having a unique identifier and corresponding to the first intra-domain path information; the first node in the path transmits to a first node in a second domain an inter-domain path establishment signaling comprising the third PATH-KEY and a second PATH-KEY to make the first node in the second domain to transmit to a second PCE query information for querying second intra-domain path information corresponding to the second PATH-KEY, generates, on the basis of a query result returned by the second PCE, and saves a fourth PATH-KEY having a unique identifier and corresponding to the second intra-domain path information; and, the first node in the path changes path information from the first node in the path to an end node in the path on the basis of a reverse signaling returned by the end node and comprising the third PATH-KEY and the fourth PATH-KEY.