The present invention includes: receiving a Path message that is sent by an upstream node and carries an ACH of the upstream node; creating a new Path message and sending the new Path message to a downstream node, where the new Path message includes the ACH capability of the upstream node; receiving a Resv message that is sent by the downstream node and carries information about an ACH capability of the downstream node; and creating a new Resv message and sending the new Resv message to the upstream node, where the new Resv message includes the ACH of the downstream node. In the embodiments of the present invention, the ACH can be negotiated between nodes on an LSP so that a node on the LSP can know an ACH of another node, which avoids loss or erroneous forwarding of a special packet transmitted on an ACH.