Abstract: 　Network failures are common on the Internet, and with mission-critical services widely applied, there grows demand for the Internet to maintain the performance in possibilities of failures. However, the border gateway protocol (BGP) can not react quickly to be recovered from them, which leads to unreliable packet delivery degrading the end-to-end performance. Although much solutions were proposed to address the problem, there exist limitations. The authors designed a software defined autonomous system (AS)-level fast rerouting (SD-FRR) to efficiently recover from interdomain link failures in the administrative domain. The approach leverages the principle of software defined networking (SDN) to achieve the centralized control of the entire network. By considering routing policies and BGP decision rules, an algorithm that can automatically find a policy-compliant protection path in case of link failure was proposed. The OpenFlow forwarding rules are installed on routers to ensure data forwarding. Furthermore, to deactivate the protection path, how to remove flow entries based on prefixes was proposed. Experiments show that the proposal provides effective failure recovery and does not introduce significant control overhead to the network.

Key words: BGP, fast reroute, SDN, SD-FRR, AS, OpenFlow, routing policy