Flow-table Distribution in Software-Defined Networks

Flow-table Distribution in Software-Defined Networks

林志浩(Chih-hao Lin)

指導教授 ： 張貴雲

國立中央大學/資訊電機學院/資訊工程學系/碩士(2014年)

摘要

一般使用三元內容定址記憶體(Ternary Content Addressable Memory)，實作交換器裡的SDN路由表(Flow-table)。因交換器硬體規格不同只能提供少量的TCAMs。在軟體定義網路(Software-define network)中，需要提供各式各樣的服務，像是安全防護、虛擬私人網路(VPN)、服務質量(QoS)、負載平衡和流量監控，而這些服務都需要龐大的規則(Rule)去完成。而要如何將這些龐大的規則存放在SDN交換器是個嚴重的問題。
在本篇論文中，我們的方法將完整的路由表(Full flow-table)分割成幾個小的部分路由表(partial flow-table)，再將這些部分路由表分配給網路中的各個交換器。我們的目標是減少各個交換器使用的儲存空間和平衡各個交換器負載平衡。更重要的是在加入新的規則時，減少了控制者(controller)通訊成本。

關鍵字

軟體定義網路 ； 三元內容定址記憶體 ； 路由表 ； 交換器 ； 控制者

並列摘要

The switch's flow-table is usually implemented by using ternary content addressable memory (TCAMs). In SDN, TCAM supports just a few thousand or tens of thousands of entries (which is according to the different hardware). However, SDN needs to provide a variety of services, such like the security services, virtual private network (VPN), quality of service (QoS), load balancing, traffic monitoring and accounting, network address translation (NAT), etc. These services will need a lot of policies to complete, which is mapping to a large number of rules. So, how to store all the rules in the SDN switch becomes a serious problem. Our method decomposes a large SDN flow-tables into small ones and then distributing them across the network. Our goal is to reduce the total number of table entries and also balance the number of table entries in each switch. When the SDN tables update, our method also reduces the controller communication cost.

參考文獻

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