FASIC: 在軟體定義網路中具有 快速修復及適應性延展特性的頻內控制平面設計

Abstract

為了使軟體定義網路可靠地運行，網路的控制平面必須要保持穩定以確保封包路由及轉送的正確性。對頻內(In-band)控制而言，網路控制訊號流經與資料平面相同的網路，而沒有一個專屬控制平面的網路，因此，資料平面的網路錯誤可能會使交換機被隔離於控制平面之外，並導致錯誤的封包轉送。在本篇論文中，我們設計了FASIC 控制平面，FASIC 能夠以自治化的方式初始化控制網路，並能藉由控制線路切換來適應性地延展網路的控制平面。我們利用開源的Open vSwitch、OpenDayLight OVSDB Integration 及Floodlight controller來展示FASIC 是一項可行的頻內控制平面設計方案。實驗結果顯示，和標準Open vSwitch 相比，FASIC 在硬性斷線的情況下能減少87.83%的控制平面斷線時間; 在壅塞後斷線的情況下能達到零斷線時間，即預防性的控制線路切換能在高負載的狀態下避免控制線路斷線。

To operate a reliable SDN network, the control plane should be robust in order to guarantee the correctness of traffic forwarding. For in-band control, the control traffic flows along with the data plane without a dedicated control network. Thus, the failure of data plane may isolate the switches from control plane and lead to erroneous forwarding behavior. In this paper, we design a control plane, FASIC, which can bootstrap the control network in an autonomous manner and adaptively span the control plane with the control-link switching mechanism. By implementing our design with Open vSwitch (OVS), OpenDayLight OVSDB Integration (ODL-OVSDB) and Floodlight controller, we demonstrate that FASIC is an in-band control solution which is feasible under support of the available SDN and OpenFlow resources. Compared with standard OVS, the experimental result shows that FASIC reduces 87.83% of control plane downtime under hard link failure and incurs zero downtime under congestion. The preemptive control-link switching can prevent the control-link failure when it suffers from heavy traffic load.