分項三

可程式化交換機之技術研發

(Technology Development for Programmable Switch)

        可程式交換機平台的價值在於可以因應各種新型態的核心網路需求,動態的增加路由功能,用軟體定義方式來解決交換機被硬體所限制的問題。此外,搭配INT(In-Band Network Telemetry)進行網路狀態之遙測,並開發各式網路自動路徑修復、自動效能調校、自動組態設定…等,智慧自動化之機制。

5年與所提研究主題相關之研究績效

        P4 語言以及P4交換機 [1]是較新的研究領域。Stanford大學、Princeton大學、Google、Microsoft、Intel 以及 Barefoot的研究人員在2014年首度發表此研究的構想。網通市場上尚未有能完整支援P4的交換機,因此P4相關論文數量仍然非常少。我們過去三年執行科技部SDN產學大聯盟計畫,在國際知名的會議或期刊中發表眾多SDN和可程式化網路相關論文(如 [2] [3] [4] [5] [6] [7] [8]),且在P4交換機的模擬軟體上設計和開發多樣且有價值的P4程式。

今日LTE/IoT 資料層以及未來5G的核心網路的語音及影像電話(VoIP)都採用SIP及RTP協定,因此需要進行SIP及RTP 的packet header轉換 [9]。我們過去致力於相關演算法的設計與實作,發表許多期刊論文以及專利,例如SIP封包穿越NAT與IPv4-IPv6轉換提供快速處理機制 [10] [11] [12] [13] [14] [15],以及SIP及RTP封包處理機制 [16] [17] [18] [19] [20] [21] [22] [23]。我們發明的SIP及RTP相關機制,效能雖佳,然而因為現有的LTE硬體(SGW、MGW與CSCF)的限制,難以無限擴充執行我們的演算法,此問題在過去十年無法解決。由於P4交換機有快速變換packet header的能力,運用在我們發明的機制,將如虎添翼,解決多年來的問題。然而要利用P4交換機快速變換packet header的能力以達成快速SIP及RTP轉換機制並不簡單,需要相當深入的研究。換言之,P4交換機的引進,會將我們過去的研究轉換成全新的P4交換機問題。例如2005年我們發明的SIP轉換機制至今仍被採用 [10] [14],而由IPv4轉換為IPv6封包時,封包長度會增加20位元組。反之會減少20位元組。本計畫以Barefoot P4交換機研發TrGW中IPv4-IPv6轉換功能,將充分發揮P4交換機的特色,在P4交換機發展出全新的技術。未來本計畫將建置P4交換機作為5G/LTE/IoT的資料層的主要元件,把過去使用交換機處理器(Processor)的系統設計與實作改為使用P4交換機晶片中的 pipeline來實現,如此將可以大幅提昇這些系統功能的執行速度,達到P4交換機的 line rate封包處理速度,在5G 資料層(傳輸層及核心網路)完成國際級的研發成果。

短中長期效益目標

        分項C研發的P4網路測試平台會超越標竿單位ONF及EURECOM,也會是全世界首見之測試平台。

短期目標:建構小型P4/INT網路測試平台進行P4的初步研究和測試,並且搭配In-Band Network Telemetry (INT)之技術,遙測封包流經P4交換機之各項狀態以進行基本網路優化、自動化之功能開發。此平台將是亞洲第一個由學術單位建置可提供學生進行P4/INT之各式應用開發,培育學生成為P4工程師,未來期望夠能協助產業界開發各式應用。

中期目標:藉由P4及INT技術,收集封包經過P4交換機之壅塞狀態與頻寬使用狀況,進而開發各式進階功能如:5G網路資料層的可用性及效率強化、IoT封包聚合及效能提升、網路效能改善、系統自動偵錯…等,並培育學生於P4/INT領域在Open Source做出貢獻,提升實務與技術研發能力。

長期目標:擴增P4/INT測試網路平台,依研究的不同需要而有更大的網路拓樸和組態,並且預期能夠導入校園網路或部份行動網路之真實流量進行場域測試。藉由P4/INT平台吸引國內大專院校之研究團隊學習並進行P4/INT之相關研究,提升我國在P4領域之技術人材,並藉由這些人才之技術研發能力協助國內廠商進行產品功能/附加價值之提升,以及解決廠商所遇到之問題,並持續在Open Source做出貢獻,加速台灣於P4相關產業之商業化,進而帶動整體產業之產值。

團隊成員研究成果

[1] P. Bosshart, D. Daly, G. Gibb, M. Izzard, N. McKeown, J. Rexford, C. Schlesinger, D. Talyco, A. Vahdat, G. Varghese and D. Walker, “P4: Programming Protocol-Independent Packet Processors,” ACM SIGCOMM Computer Communication Review, vol. 44, no. 3, pp. 88-95, 2014.
[2] S.-Y. Wang and I.-Y. Lee, “MiniReal: A Real SDN Network Testbed Built over an SDN Bare Metal Commodity Switch,” in IEEE International Conference on Communications (ICC), Paris, France, 2017.
[3] S.-Y. Wang, C.-H. Chang, Y.-H. Hsieh and C.-L. Chou, “Design and Implementation of a Packet-in Buffer System for SDN Switches,” in IEEE Symposium on Computers and Communications (ISCC), Heraklion, Greece, 2017.
[4] S.-Y. Wang, S.-Y. Liu and C.-L. Chou, “Design, Implementation and Performance Evaluation of Software OpenFlow Flow Counters in a Bare Metal Commodity Switch,” in IEEE Symposium on Computers and Communication (ISCC), Messina, Italy, 2016.
[5] L.-W. Cheng and S.-Y. Wang, “Application-Aware SDN Routing for Big Data Networking,” in IEEE Global Communications Conference (GLOBECOM), San Diego, CA, USA, 2015.
[6] H.-W. Hsu, K.-L. Huang, Y.-C. Kao, S.-C. Tsai and Y.-B. Lin, “Deploying WLAN Service with OpenFlow Technologies,” International Journal of Network Management, vol. 27, no. 3, 2017.
[7] S.-C. Su, Y.-R. Chen, S.-C. Tsai and Y.-B. Lin, “Detecting P2P Botnet in Software Defined Networks,” Security and Communication Networks, pp. 1-17, 2017.
[8] C.-C. Chen, Y.-R. Chen, W.-C. Lu, S.-C. Tsai and M.-C. Yang, “Detecting Amplification Attacks with Software Defined Networking,” in IEEE Conference on Dependable and Secure Computing, Taipei, Taiwan, 2017.
[9] Y. C. Sung, Y.-S. Ho, Y.-B. Lin, J.-C. Chen and C.-H. Rao, “Voice/Video Quality Measurement for LTE Services,” Accepted and to appear in IEEE Wireless Communications, 2017.
[10] W.-E. Chen, C.-Y. Su and Y.-B. Lin, “NCTU SLT: A Socket-layer Translator for IPv4-IPv6 Translation,” IEEE Communications Letters , vol. 9, no. 10, pp. 865-867, 2005.
[11] W.-E. Chen and P.-J. Lin, “A Performance Study for IPv4-IPv6 Translation in IP Multimedia Core Network Subsystem,” International Journal of Communication Systems, vol. 23, no. 8, pp. 929-944, 2010.
[12] W.-E. Chen, C.-Y. Hsu and B.-E. Chen, “Network Address Translation Traversal System and Method for Real-time Communications”. USA Patent 9736316, 15 8 2017.
[13] W.-E. Chen, B.-E. Chen and C.-W. Su, “Signaling Control System and Method for USE in NAT Traversal System”. US Patent 0063781, 2017.
[14] W.-E. Chen, Y.-B. Lin and A.-C. Pang, “An IPv4-IPv6 Translation Mechanism for SIP Overlay Network in UMTS All-IP Environment,” IEEE Journal on Selected Areas in Communications, vol. 23, no. 11, pp. 2152-2160, 2005.
[15] W.-E. Chen, Y.-L. Huang and H.-C. Chao, “NAT Traversing Solutions for SIP Applications,” EURASIP Journal on Wireless Communications and Networking, 2008.
[16] Y.-K. Chen and Y.-B. Lin, “IP Connectivity for Gateway GPRS Support Node,” IEEE Wireless Communications, vol. 12, no. 1, pp. 37-46, 2005.
[17] W.-E. Chen, H.-N. Huang and Y.-B. Lin, “Modeling VoIP Call Holding Times for Telecommunications,” IEEE Network, vol. 21, no. 4, pp. 22-28, 2007.
[18] C.-H. Gan and Y.-B. Lin, “Push-to-Talk Service for ITS,” IEEE Transactions on Intelligent Transport Systems, vol. 8, no. 3, pp. 391-399, 2007.
[19] M.-H. Tsai and Y.-B. Lin, “Talk Burst Control for Push-to-Talk over Cellular,” IEEE Transactions on Wireless Communications, vol. 7, no. 7, pp. 2612-2618, 2008.
[20] Y.-C. Sung and Y.-B. Lin, “IPsec-based VoIP Performance in WLAN Environments,” IEEE Internet Computing, vol. 12, no. 6, pp. 77-82, 2009.
[21] Y.-B. Lin, M.-H. Tsai and Y.-K. Chen, “Bearer Reservation with Preemption for Voice Call Continuity,” IEEE Transactions on Wireless Communications, vol. 8, no. 5, pp. 2716-2725, 2009.
[22] H.-Y. Lee and Y.-B. Lin, “Credit Pre-reservation Mechanism for UMTS Prepaid Service,” IEEE Transactions on Wireless Communications, vol. 9, no. 6, pp. 1867-1873, 2010.
[23] Y.-B. Lin, M.-H. Tsai and Y.-K. Tu, “IMS Emergency Services: A Preliminary Study,” IEEE Wireless Communications, vol. 18, no. 1, pp. 6-14, 2011.
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