軟體定義網路(Software Defined Network)在近幾年已經成為骨幹網路及資料庫網路中新穎的網路解決方案，因為在軟體定義網路中會有一個中央控制中心可以改變每個資料流所流動的路徑進而達到自訂的網路目標。要改變每個資料流的路徑必須經由增加優先權較高的路由規則到路由器中，路由表一般來說是儲存在TCAM中，然而因為TCAM是非常昂貴的，因此在軟體定義網路中便因為這樣可以改變路徑的機制而有了新的網路資源限制:路由表大小。在這篇論文中我們同時考慮了每個使用者的服務品質，因此論文的目標則著重於在軟體定義網路的環境下最大化每個使用者的服務品質。綜觀上述講到的各點在這篇論文中我們提出了一個優化的問題，並且證明這是一個NP-hard的問題，隨後提出一個直覺的Heuristic以及做了一連串的實驗來證實我們演算法的效能。

Software Defined Networks (SDNs) are becoming the leading technology behind many traffic engineering solutions, both for backbone and data-center networks, since it allows a central controller to manage the path of the flows according to specific objective. The central controller manage the path of the flows via additional assignment of rules in the rule table of the networking devices. Typically the rule table is stored in the ternary content addressable memory (TCAM). However, TCAM is expensive such that it is limited in the networking devices and would be the bottleneck of the network. In this thesis, we concentrate on solving the global network problem in the environments which the rule table size in forwarding devices is limited. Meanwhile, we consider the problem associated with the quality of service. We formulate this problem as an NP-hard optimization problem and propose a heuristic for it.

Chapter 1 Introduction
Chapter 2 Related Works
Chapter 3 Bounded Rule Table Size Maximum QoS Problem
Chapter 4 The Proposed Algorithm
Chapter 5 Experimental Study
Chapter 6 Conclusion

[1] N. McKeown, T. Anderson, H. Balakrishnan, G. Parulkar, L. Peterson, J. Rexford, S. Shenker, and J. Turner, "Openflow: Enabling innovation in campus
networks," SIGCOMM Comput. Commun. Rev., pp. 69-74, Mar. 2008.
[2] U. Hoelzle,"Opening address: 2012 open network summit,"http:""www.opennetsummit.org"archives"apr12"hoelzle-tue-openflow.pdf, Date Retrieved, vol. 8, no. 08, p. 2014, 2012.
[3] S. Jain, A. Kumar, S. Mandal, J. Ong, L. Poutievski, A. Singh, S. Venkata, J.Wanderer, J. Zhou, M. Zhu, J. Zolla, U. H olzle, S. Stuart, and A. Vahdat, "B4: Experience with a globally-deployed software defined wan," SIGCOMM Comput. Commun. Rev., vol. 43, no. 4, pp. 3-14, Aug. 2013.
[4] R. Narayanan, S. Kotha, G. Lin, A. Khan, S. Rizvi, W. Javed, H. Khan, and S. A. Khayam, "Macroflows and microflows: Enabling rapid network innovation
through a split sdn data plane," in Software Defined Networking (EWSDN), 2012 European Workshop on. IEEE, 2012, pp. 79-84.
[5] B. Stephens, A. Cox, W. Felter, C. Dixon, and J. Carter, "Past: Scalable ethernet for data centers," in Proceedings of the 8th international conference on Emerging networking experiments and technologies. ACM, 2012, pp. 49-60.
[6] R. Cohen, L. Lewin-Eytan, J. S. Naor et al., "On the effect of forwarding table size on SDN network utilization," in INFOCOM, 2014 Proceedings IEEE. IEEE, 2014, pp. 1734-1742.
[7] M. Yu, J. Rexford, M. J. Freedman, and J. Wang, "Scalable flow-based networking with difane," ACM SIGCOMM Computer Communication Review, vol. 41, no. 4, pp. 351-362, 2011.
[8] Y. Kanizo, D. Hay, and I. Keslassy, "Palette: Distributing tables in software-defined networks," in INFOCOM, 2013 Proceedings IEEE. IEEE, 2013, pp. 545-549.
[9] N. Kang, Z. Liu, J. Rexford, and D. Walker, "Optimizing the one big switch
abstraction in software-dened networks," in Proceedings of the ninth ACM conference on Emerging networking experiments and technologies. ACM, 2013, pp. 13-24.
[10] R. Karp, "Reducibility among combinatorial problems," in Complexity of Computer Computations. Plenum Press, 1972, pp. 85-103
[11] R. Albert and A.L. Barabasi. "Statistical mechanics of complex networks." Reviews of Modern Physics, Vol. 74, pp. 47-97, 2002.
[12] C. Guo, G. Lu, D. Li, H. Wu, X. Zhang, Y. Shi, C. Tian, Y. Zhang, and Songwu Lu. "BCube: A high performance, server-centric network architecture for modular data centers." Proceedings of the ACM SIGCOMM 2009 conference on Data communication, 2009.
[13] http:""sndlib.zib.de"home.action
[14] T. Lan, D. Kao, M. Chiang, and A. Sabharwal, An axiomatic theory of fairness in network resource allocation, in Proceedings of IEEE INFOCOM. IEEE, 2010, pp. 1-9.
[15] D. Bertsekas and R. Gallager, Data Networks (2Nd Ed.). Upper Saddle River, NJ, USA: Prentice-Hall, Inc., 1992.
[16] M. Allalouf and Y. Shavitt, Centralized and distributed algorithms for routing and weighted max-min fair bandwidth allocation, Networking, IEEE"ACM
Transactions on, vol. 16, no. 5, pp. 1015-1024, 2008.
[17] G. R etv ari, J. J. B r o, and T. Cinkler, Fairness in capacitated networks: A
polyhedral approach, in INFOCOM 2007. 26th IEEE International Conference
on Computer Communications. IEEE. IEEE, 2007, pp. 1604-1612.
[18] E. Danna, S. Mandal, and A. Singh, A practical algorithm for balancing the
max-min fairness and throughput objectives in traffic engineering, in INFOCOM, 2012 Proceedings IEEE. IEEE, 2012, pp. 846-854.
[19] M. Moshref, M. Yu, A. Sharma, and R. Govindan, vcrib: Virtualized rule management in the cloud, in Proc. NSDI, 2013.
[20] F. Giroire, J. Moulierac, and T. K. Phan, Optimizing rule placement in software-defined networks for energy-aware routing, in Global Communications Conference (GLOBECOM), 2014 IEEE. IEEE, 2014, pp. 2523-2529.
[21] X.-N. Nguyen, D. Saucez, C. Barakat, and T. Turletti, Officer: A general optimization framework for openflow rule allocation and endpoint policy enforcement, in The 34th Annual IEEE International Conference on Computer Communications (INFOCOM 2015), 2015.
[22] S. Agarwal, M. Kodialam, and T. Lakshman, Traffic engineering in software
defined networks, in INFOCOM, 2013 Proceedings IEEE. IEEE, 2013, pp. 2211-
2219.
[23] H. Huang, P. Li, S. Guo, and B. Ye, The joint optimization of rules allocation and traffic engineering in software defined network, in Quality of Service (IWQoS), 2014 IEEE 22nd International Symposium of. IEEE, 2014, pp. 141-146