This read-create integer is the path-option explicit-path identifier used to reference a specific pre-defined explicit path configuration for this LSP. It lets an administrator associate this path entry with a named or numbered explicit-path definition elsewhere in the configuration rather than specifying hop-by-hop details inline. For example, setting csMplsPathIdentifier to reference explicit path 42 would apply that path's pre-configured hop list to this LSP's active path.