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On Scalability of Software-Defined Networking. Author: Soheil Hassas Yeganeh, Amin Tootoonchian, and Yashar Ganjali, University of Toronto Publisher: IEEE Communications Magazine 2013 Presenter: Sih-An Pan, Date: 2013/10/2. Introduction.
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On Scalability ofSoftware-Defined Networking Author:Soheil Hassas Yeganeh, Amin Tootoonchian, and Yashar Ganjali, University of Toronto Publisher: IEEE Communications Magazine 2013 Presenter: Sih-An Pan, Date: 2013/10/2
Introduction • Moving the control function out of data plane elements is the common denominator among software-defined networking (SDN) proposals in the research community. • The common perception that control in SDN is centralized leads to concerns about SDN scalability and resiliency.
Advantages of SDN • High Flexibility • Vendor-agnostic • Programmability • Centralized Network View
Centralized Controller • A. Tootoonchian et al., “On Controller Performance in Software-Defined Networks,” Proc. USENIX HotICE’12 • Simple modifications to the NOX controller • Boosts its performance by an order of magnitude on a single core • DevoFlow (ACM Sigcomm 2011) • With support from ASIC • Short-lived flows are handled in the data path • Only larger flows are forwarded to the controller • Reducing the load on controller
Distributed Controller Design Tradeoff • Strictly Consistent Centralized Viewwill hinder response time and throughputas the network scales • It is NOTalways feasible to achieve strong consistency while maintaining availability and partition tolerance • Selecting an apt consistency level is an important design trade-off in SDN
Distributed Controller • HyperFlow(INM Conf. 2010) • Synchronizes network state among multiple controller • Giving the controller an illusion of control over the whole network
Opportunities and Challenges • Testing and Verification • Without the right tools in place, troubleshooting becomes a major problem for networks as they grow. • Extensibility • Current SDN implementations take a pragmatic approach in supporting only well-known popular protocols that are readily supported by most equipment and chip vendors • API and function for new protocol