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An Optimized Scheme for Mobile Learning on IP-Based Network Using SIP 549 To: <sip:alice@nbut.cn> Call-ID: fverVterCnrc.PmB9P5OeciLSb@192.168.0.100 Contact: <sip:alice@192.168.0.100:5060> Authorization: Digest user- name="alice@nbut.cn",realm="nbut.cn",nonce="dd2de673348 f1d19337082e347115bf1",uri="sip:nbut.cn",response="a487 130029eae4a850da14342dfaf682",algorithm=MD5 SIP/2.0 200 OK From: <sip:alice@nbut.cn>;tag=nVfdNPfdu7qq_tnj*t4- U39aC8 To: <sip:alice@nbut.cn>;tag=6101 Call-ID: fverVterCnrc.PmB9P5OeciLSb@192.168.0.100 Contact: <sip:alice@192.168.0.100:5060>;expires=3600 REGISTER sip:nbut.cn SIP/2.0 From: <sip:alice@nbut.cn>;tag=ImJMioJMu7qq_tnj*t4- V.QmE_ To: <sip:alice@nbut.cn> Call-ID: xgA5+eA5H+Pdgz4AeznPA.Q_E8@192.168.0.100 Contact: <sip:alice@192.168.0.100:5060> Authorization: Digest user- name="alice@nbut.cn",realm="nbut.cn",nonce="dd2de673348 f1d19337082e347115bf1",uri="sip:nbut.cn",response="a487 130029eae4a850da14342dfaf682",algorithm=MD5 SIP/2.0 200 OK From: <sip:alice@nbut.cn>;tag=ImJMioJMu7qq_tnj*t4- V.QmE_ To: <sip:alice@nbut.cn>;tag=6792 Call-ID: xgA5+eA5H+Pdgz4AeznPA.Q_E8@192.168.0.100 Contact: <sip:alice@192.168.0.100:5060>;expires=3600 In the flow of playing courseware and updating session as illustrated in figure 6, Alice chooses to play a courseware, which could be retrieved from her courseware list. This triggers the user entity to send a SIP INVITE request message to the m- learning server, with a courseware URI such as sip:coursewareA@nbut.cn in its re- quest URI and an IP address of 192.168.0.100 both in contact head field and SDP. After receiving this message, the server will prepare for playing this courseware. Af- ter it is done, the server will respond with a 200 OK message to Alice, and Alice will send back an ACK message to acknowledge the receiving of 200 OK. After the 550 S. Fan et al. Fig. 6. Process of playing courseware and updating session three-way SIP signal is completed, an RTP media stream will be sent directly to Alice from m-learning server. The stream can be either audio or video. The user entity of Alice will properly play it for Alice. If Alice moves and IP address changes to 192.168.1.200, the user entity will send an UPDATE message with a new address of 192.168.1.200 both in contact head field and SDP to update the SIP session. Then the RTP stream could be sent to the new address and the future SIP message in the same session could be sent to Alice correctly. 5 Conclusion and Future Work In this paper we first analyzed the attributes that a general m-learning system should cover, then explored the advantages of applying SIP in m-learning systems. An opti- mized scheme for m-learning using SIP is proposed after that. We can see that by introducing SIP, we get excellent personal mobility and service mobility that are im- possible to get in traditional m-learning systems using HTTP. More interactive and An Optimized Scheme for Mobile Learning on IP-Based Network Using SIP 551 real-time m-learning applications can be implemented based on the optimized archi- tecture. Courseware is available to be subscribed and played anytime and anywhere, sessions could be continued and updated seamlessly with the movement of users. However, SIP mobility cannot support TCP connections, while there are still many m- learning applications running on TCP, such as HTTP and FTP services. This problem can be solved by integrating Mobile IP technology into SIP. The integration of SIP and MIP on m-learning is left for future study. Moreover, the current m-learning sys- tem only includes basic e-learning functions, more complex applications, like multi- party conference, courseware sharing, and virtual whiteboard, can be added in the future. Acknowledgements This paper is partially supported by NSCF 2007A610047. References 1. Iva, B., Pierre, V., Murat, K.: Virtual Classroom for Multimedia Teaching on WWW. In: 32nd ASEE/IEEE Frontiers in Education Conference (2002) 2. Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.R., Peterson, J., Sparks, R., Handley, M., Schooler, E.: SIP: session initiation protocol. RFC 3261, IETF (2002) 3. Mikic, F., Anido, L.: M-learning Standardization.: Concepts and New Ideas about Learner Profile. Education for the 21st Century - Impact of ICT and Digital Resources (2006) 4. Wagner, E.D.: Enabling Mobile Learning. Educause Review 40, 40–53 (2005) 5. Schulzrinne, H., Casner, S., Frederick, R., Jacobson, V.: RTP: A Transport Protocol for Real-Time Applications. RFC 3550, IETF (2003) 6. Crocker, D., Overell, P.: Augmented BNF for Syntax Specifications: ABNF. RFC 4232, IETF (2005) 7. Handley, M., Jacobson, V., Perkins, C.: SDP:Session Description Protocol. RFC 4566, IETF (2006) 8. Johnston, A.B.: SIP: Understanding the Session Initiation Protocol, 2nd edn. (2004) 9. Perkins, C.I.: Mobility Support for IPv4. RFC 3344, IETF (2002) 10. Wedlund, E., Schulzrinne, H.: Mobility Support using SIP. In: Proc. ACM WoWMoM 1999, Seattle (1999) 11. Pozzi, F.: The Impact of m-Learning in School Contexts: An “Inclusive” Perspective. Uni- versal Access in Human-Computer Interaction. Applications and Services (2007) 12. Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., Leach, P., Luotonen, A., Stewart, L.: HTTP Authentication: Basic and Digest Access Authentication. RFC 2617, IETF (1999) Author Index Aouag, Sofiane 497 Blumberg, Fran C. 477 Cao, Yiwei 253 Chan, Po-Chou 332 Chang, Han-Bin 232 Chang, Hsuan-Pu 529 Chang, Wen-Chih 178, 221, 241, 275 Chang, Yuan-Hou 18, 322 Chao, Louis R. 232, 241, 529 Chen, Jianer 285 Chen, Jui-Hung 241 Chen, Kuen-Chi 178 Chen, Ling 187 Chen, Shihong 79 Chen, Tianding 314 Chen, Xi 79 Chen, Yung-Fu 332 Chiu, Yan-Da 275 Choi, Kwansun 196, 208 Chou, Yu-Min 221 Chung, Pei-Yun 87 ´ Cukuˇsi´c, Maja 99 de Castro, Juan P. 167 Fan, Jianbo 541 Fan, Lei 468 Fan, Shaojing 541 Fang, Fang 468 Fern´andez-Manj´on, Baltasar 253, 486 Fu, Fong-Ling 265 Gao, Jian-Bin 87 Grani´c, Andrina 99 Grigoriadou, Maria 27 Halatsis, Constantine 27 Han, Saeron 196, 208 He, Zhongkun 541 Hong, Min 208 Hornung, Christoph 99 Hsu, Hui-Huang 232 Hu, Zhihui 344 Jeon, Changwan 196, 208 Jeon, Heunggu 196, 208 Jeong, Ok-Ran 1 Kim, Dongsik 196, 208 Kim, Won 1 Klamma, Ralf 253 Koper, Rob 132 Lai, Yen-Shou 18, 322 Laih, Chi-Sung 87 Lee, Chen-Yu 529 Lee, Sunheum 196 Leontidis, Makis 27 Leung, Howard 344 Li, Bin 398 Li, Fei 398 Li, Haifei 145 Li, Kedong 413 Li, Mao-Fan 275 Li, Yong-Na 477 Li, Zhenlong 434 Liang, Wanjie 296 Liao, Hsiu-Li 8 Liao, Ya-Chin 332 Lin, Chi-San 87 Lin, Hsuan-Hung 332 Lin, Suxian 424, 446 Lin, Suxian 521 Linckels, Serge 509 Liu, Guangdong 145 Liu, Qingtang 49, 69 Lu, Hsi-Peng 8 Luo, Nianlong 111 Luo, Qian 59 Mao, Yuxin 457 Mart´ınez-Ortiz, Iv´an 486 Meinel, Christoph 509 Miao, Yongwu 132 Moon, Ilhyun 196, 208 Moreno-Ger, Pablo 253, 486 Mu˜noz, Mar´ıa F. 167 554 Author Index Nazemi, Kawa 99 P´erez, Mar´ıa ´ A. 167 Po pescu, Elvira 122 Qi, Li 39 Qiu, Jiangtao 59 Regueras, Luisa M. 167 Repp, Stephan 509 Sheng, Yu 285 Shih, Timothy K. 529 Sierra, Jos´e Luis 253 Sierra-Rodr´ıguez, Jos´e Luis 486 Sloep, Peter 132 Spaniol, Marc 253 Sun, Zhimei 49 Tan, WenAn 424, 446, 521 Tang, Anqiong 446 Tang, Chang jie 59 Tao, Congwu 398 Tian, Wenya 457 Toubekis, Georgios 253 Tsai, Hung-Hsu 18 Verd´u, Elena 167 Verd´u, Mar´ıa J. 167 Wang, Chun-Chia 529 Wa ng, Feng 304 Wa ng, Jianxin 187, 285 Wang, Kuo-An 332 Wang, Shujuan 69 Wa ng, Te-Hua 241 Wang, Weiping 285 Wa ng, Xiaodan 468 Wang, Xin 39 Wang, Yonggu 413 Wang, Zhigang 405 Wang, Zhiwen 390 Wen, Jia-Rong 87 Woo, Sangyeon 208 Wu, Wan-Chi 87 Wu, Xiyuan 145 Xiao, Kun 79 Xu, Kaikuo 59 Xu, Yun 344 Yang, FuJun 446 Yang, Fujun 521 Yang, Heng-Li 157 Yang, Ya-Ting Carolyn 87 Yang, Yun 424, 521 Yao, Yuankun 366 Yeh, Shu-Wei 529 Ying, Ming-Hsiung 157 Yu, Pao-Ta 18, 322 Yu, Sheng-Chin 265 Yuan, Fang 39 Zhang, Xinyu 111, 405 Zhang, Xue 446 Zhang, Xue-Min 477 Zhang, Yongping 541 Zhao, Jianhua 377 Zhao, Jianmin 296 Zhao, Xianhua 424, 521 Zhao, Xiaoming 434 Zheng, Li 111 Zheng, Qinghua 145 Zheng, Xiaoli 304 Zhou, Weiw ei 187 Zhu, Chengsong 356 Zhu, Xinzhong 296 Zhu, Yaoting 356 . by integrating Mobile IP technology into SIP. The integration of SIP and MIP on m-learning is left for future study. Moreover, the current m-learning sys- tem only includes basic e-learning. Schulzrinne, H.: Mobility Support using SIP. In: Proc. ACM WoWMoM 1999, Seattle (1999) 11. Pozzi, F.: The Impact of m-Learning in School Contexts: An “Inclusive” Perspective. Uni- versal Access in. m-learning using SIP is proposed after that. We can see that by introducing SIP, we get excellent personal mobility and service mobility that are im- possible to get in traditional m-learning systems
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