軟體定義網路是一個新興的網路架構，引起許多研究人員和業界的關注。OpenFlow是一個協定而且是實現軟體定義網路的其中一種方法。SDN控制器利用OpenFlow和交換器溝通並管理它的流表。在OpenFlow 1.3的版本中，交換器總共有40個維度要查詢。這使得交換器的設計變的更複雜。Casado等人提出了新的網路架構，叫做fabric network [2]。他們將網路設備分成邊緣交換器和核心交換器。邊緣交換器會給封包一個標籤，核心交換器只需要查詢標籤。現今有一些方法利用標籤的方式來解決這個問題，如: shadow MAC [3]和[5]。
在此論文中，我們提出了一個基於標籤的高效能封包轉發機制。這種方法使得核心交換器只需要比對一個維度。為了減少邊緣交換器的規則數，我們將最後一跳的出口號編碼到MPLS欄位。我們也針對胖樹拓樸做優化。在我們的方法下，核心交換器與聚和交換器的規則數等於交換器的端口數。我們用mininet來建實驗環境。在我們的方法下，邊緣交換器的規則數約是其他方法的ㄧ半。

Software-Defined Networking (SDN) is an emerging network architecture and attracts the attention of many researchers and the industry. OpenFlow is a solution of SDN and a protocol. SDN controller uses OpenFlow to communicate with switch and manages its flow table. In OpenFlow version 1.3, there are 40 match fields. This makes the design of switch more complicated. Casado et al. describe a new network architecture, called fabric network [2]. They separate the network element into edge switch and core switch. Edge switch will tag a label onto packet header, and core switch uses this label to perform lookup. There are some methods using label-based to deal with this problem, such as shadow MAC [3] and [5].
In this thesis, we propose an efficient label-based forwarding packet scheme. In this scheme, core switch only uses one field to perform lookup. In order to reduce the number of rules in edge switch, we encode the output port number of the last hop into MPLS filed. We also propose a scheme to minimize the number of rules in fat-tree topology. In our scheme, the number of rules in core switch and aggregation switch are the same as the number of ports. We use mininet to construct the testbed. In our scheme, the number of rules in edge switch is about 50% of other methods.

[1] S. Jain , A. Kumar , S. Mandal , J. Ong , L. Poutievski , A. Singh , S. Venkata , J. Wanderer , J. Zhou , M. Zhu , J. Zolla , U. Hölzle , S. Stuart , A. Vahdat, “B4: Experience with A Globally-Deployed Software Defined WAN”, in SIGCOMM, 2013, pp. 3-14.
[2] M. Casado, T. Koponen, S. Shenker, and A. Tootoonchian, “Fabric: A Retrospective on Evoloving SDN”, in HotSDN, 2012, pp. 85-90.
[3] K. Agarwal, C. Dixon, E. Rozner, and J. Carter, “Shadow MACs: Scalable Label-switching for Commodity Ethernet”, in HotSDN, 2014, pp. 157-162.
[4] A. Schwabe and H. Karl, “Using MAC Address as Efficient Routing Labels in Data Centers”, in HotSDN, 2014, pp. 115-120.
[5] H. Farhadi and A. Nakao, “Rethinking Flow Classification in SDN”, in IEEE International Conference on Cloud Engineering, 2014, pp. 598-603.
[6] A. Hari, T. V. Lakshman, and G. Wilfong, “Path Switching: Reduced-State Flow Handling in SDN Using Path Information”, Proceedings of the 11th ACM Conference on Emerging Networking Experiments and technologies, 2015, pp. 1-7.
[7] C. Filsfils, N. Kumar Nainar, C. Pignataro, J. Camilo Cardona, and P. Francois, “The Segment Routing Architecture”, IEEE Global Communications Conference, 2015, pp. 1-6.
[8] N. McKeown, T. Anderson, H. Balakrishnan, G. Parulkar, L. Peterson, J. Rexford, S. Shenker, and J. Turner, “OpenFlow: Enabling Innovation in Campus Networks”, ACM SIGCOMM Computer Communication Review, vol. 38, no. 2, pp. 69-74, 2008.
[9] P. Bosshart, D. Daly, G. Gibb, M. Izzard, N. McKeown, J. Rexford, C. Schlesinger, D. Talayco, A. Vahdat, G. Varghese, and D. Walker, “P4: Programming Protocol-Independent Packet Processors”, ACM SIGCOMM CCR, 2014, pp. 87-95.
[10] H. Song “Protocol-Oblivious Forwarding: Unleash the Power of SDN through a Future-Proof Forwarding Plane”, in HotSDN, 2013, pp. 127-132.
[11] OpenFlow Foundation, “OpenFlow Switch Specification Version 1.3.0”. Available: https://www.opennetworking.org/images/stories/downloads/sdn-resources/onf-specifications/openflow/openflow-spec-v1.3.0.pdf
[12] A. AlGhadhban and B. Shihada, “Energy Efficient SDN Commodity Switch based Practical Flow Forwarding Method”, in Network Operations and Management Symposium (NOMS), 2016, pp. 784-788.
[13] Open vSwitch. Available: http://openvswitch.org
[14] Ryu SDN Framework. Available: https://osrg.github.io/ryu
[15] B. Lantz, B. Heller, and N. McKeown, “A Network in a Laptop: Rapid Prototyping for Software-Defined Networks”, in Proceedings of the 9th ACM SIGCOMM Workshop on Hot Topics in Networks, 2010, pp. 19:1-19:6
[16] M. Al-Fares, A. Loukissas, and A. Vahdat, “A scalable, Commodity Data Center Network Architecture”, in SIGCOMM, 2008, pp. 63-74.
[17] K. Kannan and S. Banerjee, “Compact TCAM: Flow Entry Compaction in TCAM for Power Aware SDN”, in Distributed Computing and Networking, 2013, pp. 439-444.
[18] Riplpox. Available: https://github.com/MurphyMc/riplpox
[19] C. Hopps, “Analysis of an Equal-Cost Multi-Path”, RFC 2992, Internet Engineering Task Force, 2000.
[20] D. Halperin, S. Kandula, J. Padhye, P. Bahl, and D. Wetherall, “Augmenting Data Center Networks with Multi-Gigabit Wireless Links”, in Proceedings of ACM SIGCOMM, 2011, pp.38-49.