網路閘道器之動態負載平衡設計與實作

Abstract

為了追求穩定的網路服務品質（QoS）以及保持網路暢通不斷線，許多的企業以及學校都選擇配置多條對外的網路線路，如此可以使內部網路對外時擁有較高的可靠性及較好的效能。針對多路徑路由的向外負載平衡，使用權重（Weight）平均分配訊務（Traffic）是比較公平的做法，目前相關設計包含目前市售之相關設備，皆無考慮抵達率對負載平衡的影響，因此，本研究藉由分析抵達率和服務率之間的關係，創新設計出一套數學方法來動態計算權重的分配，而且經由模擬證實所設計的方法能達到提升效能的目的，最後並以修改Linux 核心的路由策略，把自動計算權重的方法加入核心中，並且自動更新轉送資訊路由表及路由快取，以保持路由資訊以及權重的一致性來實作本設計。To provide link reliability, QoS and more link bandwidth, many companies build their network infrastructure based on multiple ISPs and multiple links. However, there exist many routing problems when implementing, for example, optimal input/output load balancing in the real networks. To aim at the load balancing of multiple links at the outbound, many products have been implemented with weighted round robin routing algorithm. Unfortunately, they usually do not consider the optimal parameters of weighted round robin algorithm depending on the traffic arrival rate. In this paper, we propose a new algorithm to automatically estimate the optimal weights according to the arrival rate and link rate. From the simulation results, we show that the proposed algorithm can improve the performance. The contribution of this paper is to propose an automatic weight tuning and to implement on the Linux operation system.