关键词: 边界网关协议（BGP）, 域间路由, 路由收敛, 策略冲突, 振荡抑制

Abstract: BGP (border gateway protocol) allows each AS (autonomous system) in the network to set its own routing policy to choose or advertise routing. While BGP routing policy configuration becomes flexible for autonomy, the routing policy conflict may emerge, causing routing flapping and diverging with network performance reducing greatly. This paper proposes a flap damping mechanism to solve BGP routing policy conflict. In this mechanism, the flap paths are detected by analyzing routing advertisement messages, and the local preference attribute values of the paths are adjusted according to the flap times, making the local preference attribute values of stable paths be greater than those of the flap paths. Then, the stable paths are selected with higher priorities than the flap ones in routing decision phase. Thus, the flap paths are damped, helping to solve the BGP routing policy conflict. The proposed mechanism is implemented and deployed on prototype system, and its performance is evaluated. The results show that it has good performance.

Key words: border gateway protocol (BGP), inter-domain routing, routing convergence, policy conflict, flap damping