Embodiments provide a packet processing method. In accordance with this method, a first LSP packet can be received by a network device. The following determinations can be made: that the network device stores no LSP packet whose LSP ID and PDU type are the same as an LSP ID and PDU type of the first LSP packet; that the network device has stored a second LSP packet whose LSP ID is the same as an LSP ID of the first LSP packet and PDU type is the same as a PDU type of the first LSP packet, and that a sequence number of the second LSP packet is less than a sequence number of the first LSP packet. When one or more of these determination are made, a determination whether LSP packet digest information matching the first LSP packet exists can be made. When the LSP packet digest information matching the first LSP packet is determined to exist, the first LSP packet can be stored.