Packet lossless fast rerouting scheme with minimized buffer delay

We propose a packet lossless fast rerouting scheme at a link/node fault in an MPLS (multiprotocol label switching) network with a minimized buffer delay problem at the ingress node. The proposed scheme uses a predefined, alternative LSP (label switched path) in order to restore user traffic. We propose two restoration approaches: (i) an alternative LSP is initially allocated with more bandwidth than the protected working LSP, and, after failure recovery, the allocated bandwidth of the alternative LSP is readjusted to the bandwidth of the working LSP; (ii) the length of the protected working LSP is reduced by using segment-based restoration. In the proposed approaches, there is no buffer delay problem after failure recovery at the ingress node, and the required buffer size at the ingress node is smaller than the previous approach.