臺灣博碩士論文加值系統

現今遠端桌面應用帶給人們極大的便利。當身處外卻立即需要存取家中或公司的電腦時，只要有任何連線裝置在身邊就能夠隨時隨地進行遠端存取或是遠端協助。遠端桌面連線軟體中，最常見的莫過於Windows內建的遠端桌面連線。不過只有Windows的作業系統以及網路有公開IP才能使用。另外還有許多像是TeamViewer、Chrome遠端桌面、VNC等免費遠端桌面軟體，雖然可以跨平台使用，但是使用前必須先在電腦上安裝軟體，或是設定登入的帳號。此外，這些遠端桌面應用的傳輸效率不佳，因此對於使用者來說，它們並不適合使用來進行如雲端遊戲或是互動式多媒體的應用。
有鑑於此，我們設計並實作一個以WebRTC (Web Real-Time Communication)為基礎的即時遠端桌面服務。我們整合開放源碼的原生WebRTC程式碼將桌面即時地傳至用戶端。網路連接參數以及進行遠端控制則使用WebSocket進行傳遞。用戶端使用標準的HTML5 Web技術實作，除了可以跨平台使用外，用戶端甚至不需要安裝任何軟體，只需要打開瀏覽器就可以直接連線操作。我們亦進行實際實驗量測系統效能。在相同環境下，我們所提出的方法有更優於以VNC或RDP為基礎的方法。雖然效能比不上經過最佳化的雲端戲平台，但我們相信WebRTC的潛力可以讓開發人員建立多樣化且豐富的互動式多媒體應用。

Remote desktop applications provides ubiquitous services for people to access their desktop applications anytime and anywhere. People now can perform remote access or remote assistance by using almost any type of devices with network connectivity capabilities. Among all remote desktop solutions, the most common one might be that comes with Windows operating systems. However, it only works on Windows and a public IP address is required to host the service. There are cross platform solutions such as TeamViewer, Chrome remote desktop connection, and Virtual Network Computing. To work with these solutions, users have to install a corresponding client software to access these services. In addition, the performance of these solutions is not good enough to play with real-time applications such as cloud gaming and interactive multimedia applications.
Based on the observation, we designed and implemented a real-time remote desktop service based on WebRTC (Web Real-Time Communication). We integrated the open sourced native WebRTC codes and attempted to deliver real-time desktop applications to a client. The setup of network connection parameters and the exchange of controlling messages are performed by using the WebSocket protocol. Thus, the client can be implemented using standard HTML5 Web technology. As a result, the client works seamlessly on almost all popular platforms and a user is able to access the service by simply using a standard browser. We conduct experiments to measure the performance of our proposed approach. Given the same setups, the performance measurements show that our WebRTC based approach has better performance than VNC and RDP based approaches. Although the performance is not as good as a fully optimized cloud gaming platform, we believe that WebRTC has the potentials for developers to create diverse and fruitful interactive real-time multimedia applications.

摘要 .......................................................................................................................... Ⅰ
Abstract ................................................................................................................. Ⅱ
目次 ...................................................................................................................... Ⅲ
圖次 ........................................................................................................................ Ⅴ
表次 ....................................................................................................................... Ⅵ
第一章 前言 ............................................................................................................................. 1
第二章 相關研究 ..................................................................................................................... 3
2.1 遠端桌面 ..................................................................................................................... 3
2.2 螢幕擷取 ..................................................................................................................... 4
2.3 WebRTC ....................................................................................................... 5
2.4 小結 .............................................................................................................. 6
第三章 系統架構 ..................................................................................................................... 7
3.1 WebRTC ....................................................................................................... 8
3.1.1 ICE ............................................................................................................. 9
3.1.2 DTLS .......................................................................................... 10
3.1.3 SRTP ........................................................................................... 12
3.1.4 WebRTC Web APIs .................................................................... 13
3.1.4.1 MediaStream ...................................................................... 13
3.1.4.2 RTCPeerConnection ........................................................... 14
3.1.4.2.1 Signaling ..................................................................... 15
3.1.4.2.2 ICE Candidate ............................................................ 15
3.1.4.2.3 Offer and Answer ....................................................... 16
3.1.4.3 RTCDataChannel ................................................................ 18
3.1.5 WebRTC Native Code ................................................................ 18
3.1.5.1 Virtual Audio Device .......................................................... 20
3.2 WebSocket .................................................................................................. 20
3.2.1 Handshake Protocol .................................................................... 21
3.2.2 用戶端建立連線 ........................................................................ 22
3.2.3 伺服器建立連線 ........................................................................ 23
3.3 Desktop Capture ......................................................................................... 24
3.3.1 Change PixelFormat ................................................................... 24
3.4 Desktop Controller ..................................................................................... 25
3.5 討論 ............................................................................................................ 26
第四章 實驗結果 .................................................................................................... 27
4.1 硬體配置 .................................................................................................... 27
4.2 軟體配置 .................................................................................................... 29
4.2.1 noVNC ........................................................................................ 29
4.2.2 Guacamole .................................................................................. 30
4.2.3 HTML5 Video Tag ..................................................................... 31
4.2.4 Chrome Extension ...................................................................... 33
4.2.5 Gaminganywhere ....................................................................... 34
4.3 實驗結果 .................................................................................................... 35
4.3.1 Frame loss rate ............................................................................ 35
4.3.2 Frame delay ................................................................................ 35
4.3.3 頻寬使用率 ................................................................................ 37
第五章 結論與未來展望 ........................................................................................ 38
第六章 參考文獻 .................................................................................................... 39

Alan Johnston, John Yoakum and Kundan Singh, “Taking on webRTC in an enterprise,” Proceedings of the IEEE Communications Magazine, pp. 48–54, 2013.
Apache Guacamole: A clientless remote desktop gateway.
http://guacamole.incubator.apache.org/
Archana Jadhav, Vipul Oswal, Sagar Madane, Harshal Zope and Vishal Hatmode, “VNC ARCHITECTURE BASED REMOTE DESKTOP ACCESS THROUGH ANDROID MOBILE PHONES,” International Journal of Advanced Research in Computer and Communication Engineering Vol. 1, Issue 2, 2012.
Arto Heikkinen, Timo Koskela and Mika Ylianttila, “Performance evaluation of distributed data delivery on mobile devices using WebRTC,” Proceedings of the International Wireless Communications and Mobile Computing Conference, pp. 1036–1042, 2015.
Brian Craig Cumberland, Gavin Carius, and Andrew Muir, “Microsoft windows nt server 4.0 terminal server edition technical reference,” Microsoft Press, 1999.
Brian K. Schmidt, Monica S. Lam, and J. Duane Northcutt, “The interactive performance of slim: a stateless, thin-client architecture,” Proceedings of the seventeenth ACM symposium on Operating systems principles, pages 32–47, 1999.
Cheng-Lin Tsao, Sandeep Kakumanu, and Raghupathy Sivakumar, “SmartVNC: an effective remote computing solution for smartphones,” Proceedings of the 17th Annual International Conference on Mobile Computing and Networking, pp. 13–24, 2011.
Chih-Fan Hsu, De-Yu Chen, Chun-Ying Huang, Cheng-Hsin Hsu and Kuan-Ta Chen, “Screencast in the Wild: Performance and Limitations,” Proceedings of the 22nd ACM international conference on Multimedia, pp. 813—816, 2014.
Chih-Fan Hsu, Tsung-Han Tsai, Chun-Ying Huang, Cheng-Hsin Hsu, and Kuan-Ta Chen, “Screencast Dissected: Performance Measurements and Design Considerations,” Proceedings of the 6th ACM Multimedia Systems Conference, pp. 177—188, 2015.
Chromecast: Allow you to cast your favourite entertainment.
http://www.google.com/ chrome/devices/chromecast/.
Chun-Ying Huang, Kuan-Ta Chen, De-Yu Chen, Hwai-Jung Hsu, and Cheng-Hsin Hsu, “GamingAnywhere: The First Open Source Cloud Gaming System,” ACM Transactions on Multimedia Computing, Communications and Applications, Vol. 10, No. 1s, pp. 1:1–1:21, 2014.
Dhaval Manvar, Mayank Mishra, and Anirudha Sahoo, “Low Cost Computing Using Virtualization For Remote Desktop,” Proceedings of the 2012 Fourth International Conference on Communication Systems and Networks, pp. 1–2, 2012.
Fraida Fund, Cong Wang, Yong Liu, Thanasis Korakis, Michael Zink and Shivendra S. Panwar, “Performance of DASH and WebRTC Video Services for Mobile Users,” Proceedings of the 20th International Packet Video Workshop, pp. 1–8, 2013.
Gaikai web page, 2012.
http://www.gaikai.com/.
GamingAnywhere: An open source cloud gaming project, 2013.
http://gaminganywhere.org.
Getting Started with WebRTC.
http://www.html5rocks.com/en/tutorials/webrtc/basics/
Giridhar D. Mandyam and Navid Ehsan, “HTML5 Connectivity Methods and Mobile Power Consumption,” Qualcomm, Tech. Rep., 2012.
H. Andrés Lagar-Cavilla, Niraj Tolia, Eyal De Lara, M. Satyanarayanan and David O’Hallaron, “Interactive resource-intensive applications made easy,” Proceedings of the MIDDLEWARE2007 Proceedings of the 8th ACM/IFIP/USENIX international conference on Middleware, pp. 143—163, 2007.
Huifeng Shen, Yan Lu, Feng Wu, and Shipeng Li, “A high-performance remote computing platform,” Proceedings of the IEEE International Conference on Pervasive Computing and Communications, pp. 1–6, 2009.
Huifeng Shen, Yan Lu, Feng Wu, and Shipeng Li, “Low-cost realtime screen sharing to multiple clients,” Proceedings of the 2010 IEEE International Conference on Multimedia and Expo, pp. 980–985, 2010.
K. V. Kaplinsk, “VNC Tight encoder-data compression for VNC,” Proceedings of the 7th International Scientific and Practical Conference of Students, Post-graduates and Young Scientists Modern Techniques and Technology, pp. 155–157, 2001.
Lide Zhang, Birjodh Tiwana, Robert P. Dick, Zhiyun Qian, Z. Morley Mao, Zhaoguang Wang, and Lei Yang, “Accurate online power estimation and automatic battery behavior based power model generation for smartphones,” Proceedings of the IEEE/ACM/IFIP International Conference on Hardware/Software Codesign and System Synthesis, pp. 105–114, 2010.
Linux Terminal Server Project (LTSP): A flexible, cost effective solution
http://www.ltsp.org.
Martin Ussath, Feng Cheng, Christoph Meinel, “Insights into Encrypted Network Connections: Analyzing Remote Desktop Protocol Traffic,” Proceedings of the 24th Euromicro International Conference on Parallel, Distributed, and Network-Based Processing, pp. 585–589, 2016.
Microsoft: Remote Desktop Protocol version 6.0.
http://support.microsoft.com/kb/925876, 2008.
noVNC: VNC client using HTML5 with encryption support.
https://kanaka.github.io/noVNC/
N. Tolia, D. Andersen, and M. Satyanarayanan, “Quantifying interactive user experience on thin clients,” Proceedings of the 2006 IEEE Computer Society on Computer, pp. 46–52, 2006.
Paul Barham, Boris Dragovic, Keir Fraser, Steven Hand, Tim Harris, Alex Ho, Rolf Neugebauer, Ian Pratt and Andrew Warfield, “Xen and the art of virtualization,” Proceedings of the nineteenth ACM symposium on Operating systems principles, pp. 164–177, 2003.
Pedro Casas, Michael Seufert, Sebastian Egger, and Raimund Schatz, “Quality of Experience in Remote Virtual Desktop Services,” Proceedings of the IFIP/IEEE International Symposium on Integrated Network Management, pp. 1352–1357, 2013.
Ricardo A. Baratto, Leonard N. Kim and Jason Nieh, “Thinc: a virtual display architecture for thin-client computing,” Proceedings of the twentieth ACM symposium on Operating systems principles, pages 277–290, 2005.
Robert W. Scheifler, and Jim Gettys, “The X window system,” ACM Transactions on Graphics, Volume 5 Issue 2,, pp. 79–109, 1986.
Ryohei Komatsu and Shin-ichi Kuribayashi, “Impact of network quality deterioration on user’s perceived operability in remote desktop environments,” Proceedings of the 17th International Conference on Network-Based Information Systems, pp. 540–544, 2014.
Shi-hai Huang, Chuang Lin, An'an Luo, Zhen Chen, Xin Jiang, Kai Wang, Hui Zhang, Xue-hai Peng, “Proxy-based Security Audit System for Remote Desktop Access,” Proceedings of the 18th Internatonal Conference on Computer Communications and Networks, pp. 1–5, 2009.
TeamViewer: Remote Control.
http://www.teamviewer.com/zhTW/
T. Richardson, Q. Stafford-Fraser, K. R. Wood, and A. Hopper, “Virtual network computing,” IEEE Internet Computing, 2:33–38, 1998.
Varun Singh, Albert Abello Lozano and Jorg Ott, “Performance Analysis of Receive-Side Real-Time Congestion Control for WebRTC,” Proceedings of the 20th International Packet Video Workshop, pp. 1–8, 2013.

WebRTC Experiments: A repository of uniquely experimented WebRTC demos.
https://www.webrtc-experiment.com/
WebRTC: provides browsers with Real-Time Communications capabilities. https://webrtc.org/
WebRTC 1.0: Real-time Communication Between Browsers.
http://w3c.github.io/webrtc-pc/#conformance
WebSocket.org.
https://www.websocket.org/index.html
Ye He, Kevin Fei, Gus Fernandez, and Edward J. Delp, “Video quality assessment for Web content mirroring,” Proceedings of the Imaging and Multimedia Analytics in a Web and Mobile World, 2014.
Youming Lin and Mario Di Francesco, “Energy Consumption of Remote Desktop Access on Mobile Devices: An Experimental Study,” Proceedings of the IEEE 1st International Conference on Cloud Networking, pp. 105—110, 2012.
Yu-Chun Chang, Po-Han Tseng, Kuan-Ta Chen, and Chin-Laung Lei, “Understanding the performance of thin-client gaming,” Proceedings of the IEEE International Workshop Technical Committee on Communications Quality and Reliability, pp. 1–6, 2011.