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行動計算之研究---總計畫(III)

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(8) ˆ‚#ƒ„ †8e‰efŠ‹ €{Œ8pŽ#‘’“}~ €{l8e‰ef#”•MN –”h{c—˜™š›œžŸ%rsGy[ , (¡jƒ„ †¢£%¤i¥¦u1 §F%¨©ª€{ %«¬­z%¨˜o®¬2«¯JK#”h / ° The integration of mobile communication and distributed computing provides anytime, anywhere (ubiquitous) computing services. The integrated system is referred to as the mobile computing system. Mobile computing can be viewed from two aspects. From the view point of telecommunication, distributed computing provides intelligence so that mobile computing networks can offer advanced communication services. From the view point of computing, mobile communication significantly extends the flexibility of the end terminals of a distributed computing system. Generally, a mobile computing system consists of four layers including the radio system, the backbone network, the system software, the applications. According to the layer structure, we propose four sub-projects to study the mobile computing issues. (1) Roaming management for circuit switching (2) Roaming management for packet switching (3) Multi-channel handoff of a two-tier mobile communication gateway. 2.

(9) (4) Mobile IP-based Multicast Services The objective of this project is to develop a prototype of a mobile computing system. We will propose some algorithms to improve the performance of the existing wireless systems. }~”±² {³c´vµ{Œc´v: ¶·¸¹º ¶·¸¹º™ 1987 »™ University of Wisconsin. ¼E½¾¿À.¶¹º}~Á Â^Ã<£b†ÄbDNA bÅÆefbbefÇÈbÉÇ È.uÊ˯ U¿( Ì͹º. {[c´v: ÎÏйº ÎÏйº™ 1987 »ÑU¿¼E:Ò½¾¿À.ιº}~ÁÂ^ÃÓ /

(10) ÔÕ, ÔÕ, Web server. uÊ˯ÑU¿( ÌÍ@@Ö. {‡c´v: ׫عº ׫عº™ 1981 »ÙÚU¿ÛÕ, ¨™ 1989 »™ Southern Methodist University ¼E:TÜ¿½¾¿À.×¹º}~ÁÂ_ Mobile Computing, Computer Architecture, Distributed Systems, uÊ˯ U¿( Ì͹º. {lc´v: Ý·Þ¹º Ý·Þ¹º}~ÁÂ^Ã<£b:Tefbefßàá

(11) âbÔÕ}~ã. uÊ˯ U¿( Ü¿cÊ. The leader of the integrated and plan 3: Professor Rong-Jaye Chen Rong-Jaye Chen received the Ph.D. degree from University of Wisconsin . His research interests include algorithm design, theory of computation, DNA computing, interconnection network, mobile computing, network optimization, combinational optimization. He is now a professor in the Department of Computer Science and Engineering in Chiao-Tung University. The leader of plan 1: Professor Chu-Sing Yang Chu-Sing Yang received the Ph.D. degree in Electrical Engineering from Cheng-Kung University, in 1987. His research interests include Parallel Compiler, 3.

(12) Computer Architecture, Distributed System, Fault-Tolerant Computing and Web Server Design. He is now the chairman of the Department of Computer Science and Engineering in Cheng-Kung University. The leader of plan 2: Professor Chien-Chiao Tseng Chien-Chiao Tseng received the Ph.D. degree in Computer Science from Southern Methodist University , in 1989. His research interests include Mobile Computing, Computer Architecture, Distributed Systems. He is now a professor in the Department of Computer Science and Engineering in Chiao-Tung University. The leader of plan 4: Professor Rong-Hong Jan Rong-Hong Jan received the B.S. and M.S. degrees in Industrial Engineering, and the Ph.D. degree in Computer Science from National Tsing Hua University, Taiwan, in 1979, 1983, and 1987, respectively. His research interests include computer networks , distributed systems, network reliability , and operations research. }~”ÄbžŸäåjæçßèéêë. . i2ìXí€{°bݱbjëäå/î. 4.

(13) €{[ :f‚#ƒ„ † c´v8ÎÏÐ ÑU¿( ÌÍ ¹º E-mail8csyang@cie.nsysu.edu.tw FAX:07-5254301 . 5.

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(25) ˆ‚#ƒ„ †8e‰efŠ‹ c´v8×«Ø  U¿( ÌÍ ¹º E-mail8cctseng@csie.nctu.edu.tw Fax8(03)5724176 . package into the mobile computing environment we’ve setup. And test the supports and efficiency of modified AT&T wavelan driver on inter-subnet handoff. By means of creating a more stable and efficient mobile computing environment. We also provide a simulation model to evaluate feasibility and performance of hierarchical routing and registration architecture. In this project, we truly setup a mobile computing environment to support host mobility. Based on the environment, we improve TCP, IP and data-link layer performance to adapt to demands of high user mobility in the future.. 

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(80) ~<£ÁYZ WaveLan j5^&L Â5ù ! 215 <£ WPMHÕFA : HA þx&L4~:N`~5³8Å _‡Î^`z9ºÀhJ¬­ Ö× ØÙÚ¢£Áï”!z%@ <£ÒÓ Û'§, Ü×À_‡Î^Y Zµz‡ ÝÞßàà : ááâ ° Á*J, <=° q'ˆEœÍ<£þNO ‚/'ãUz8Å 9{|}=~b R ÜäåæÅ ÒçèéàßêÜ× 3ˆ‰YZLÝ<=|{| 45B—Qb 

(81) ˜sRLMJK <=|236Þëìíçîî7}ï ^8›€‹Š‡Ý9`Q€€ ‚ðñò¨¾L¼ÓÒÜ× v)R"# ~ðñ23 ^D þžŸBµ ÓÒÜ× kq<=pqóônÕõuv wÓÒÜ× kq ¬#$-BŽ§^ RLMoJK}ï^8Å Ø¡;01ƒ„bc k'ðñ ã²³9*‡.XYZTU* ‡²³döi¡;KÔ÷*‡ 45./01RLMYZTõo?ð ñýþ8»9YZ„àk TCPIP R Š‹|]hi3LM¬­D®E¯ <=°‹·¸Ž§^¯`JÞLM ‡oT_oJK45./018a R*‡.X/'3YZLMÞÖð ñvV8. [1]. T. Imielinski and B. R. Badrinath. Wireless mobile computing: Challenges in data management. To appear in Communications of the ACM, 1994.. [2]. B. Jabbari, G. Colombo, A. Nakajima, and J. Kulkarni. Network Issues for Wireless communications. IEEE Commmunication Magazine, January 1995.. [3]. E. Pitoura and B. Bhargava. Dealing with mobility: Issues and research challenges. Technical Report CSD-TR-93-070, Department of Computer Sciences, Purdue University, Nov. 1989.. [4]. Network Layer Mobility : An Architecture and Survey. Pravin Bhagwat, Charles Perkins, and Satish Tripathi. [5]. F. Teraoka et al. VIP: A protocol providing host mobility. Communications of the ACM, 37(8):67--75,113, Aug. 1994.. [6]. F. Teraoka, Y. Yokote, and M. Tokoro. Virtual Network: Towards Location Transparent Communiction in Large Distributed Systems. Sony Computer Science Laboratory Inc., Tokyo, Japan, 1990.. [7]. F. Teraoka, Y. Yokote, and M. Tokoro. A network architecture providing host migration transparency. In Proceedings SIGCOMM'91, pages 209--220. ACM Press, Sep. 1991.. [8]. J. Ioannidis. Protocols for mobile internetworking. PhD thesis, Department of Computer Science, Columbia University, 1993.. ¢.Uƒ 9.kq45./<=ðñ øù–°‹|6data link layer7 <=| 6network layer7  $|6transport layer7 45./01NO—Q\e45./< =bc45./

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(83) [9]. J. Ioannidis, D. Duchamp, and G. Q. Maguire. IP-based protocols for mobile internetworking. In Proceedings SIGCOMM'91, pages 235--245. ACM Press, Sep. 1991.. [17]. Pravin Bhagwat, Charles Perkins, and Satish Tripathi. Network layer mobility: An architecture and survey. IEEE Personal Comunications, pages 54--64, June 1996.. [10]. J. Ioannidis and G. Q. Maguire. The design and implementation of a mobile internetworking architecture. In USENIX Winter 1993 Conference, 1993.. [18]. D. B. Johnson and C. Perkins. Route Optimization in Mobile IP. IETF, ftp://nctuccca.edu.tw/documents/Inter net/Internet-Drafts/draft-ietf-mobileipoptim-04.txt.gz, Feb 1996.. [11]. D. Johnson, A. Myles, and C. Perkins. The Internet mobile host protocol (IMHP). Internet Draft, Feb. 1994.. [19]. [12]. A. Myles, D. Johnson, and C. Perkins. A mobile host protocol supporting rout optimization and authentication. IEEE Journal on Selected areas in Communications, 13(5):839--849, June 1995.. C. Perkins. IP Mobility Support. ftp://nctuccca.edu.tw/documents/Inter net/Internet-Drafts/draft-ietf-mobileipprotocol-17.txt.gz, May 1996.. [20]. A New Distributed Location Management Algorithm for Broadband Personal Communication Networks. Byung Chul Kim,Jin Seek Choi, and Chong Kwan Un, Fellow IEEE. [21]. Performance Evaluation of A Hierarchical Location Registration and Call Routing for Personal Communications. Chuan Wang,Member iEEE; Jianli Wang and Yanhe Fan. [22]. Reducing Location Tracking Costs in Mobile IP through Adaptive Local Registration. Thesis Proposal. David B. Johnson. R. Yavatkar and N. Bhagawat. Improving End-to-End Performance of TCP over Mobile Interworks. Department of Computer Science, University of Kentucky, 1995.. [23]. NCR, WaveLAN Design http://www.ncr.com. [24]. NCR, WaveLAN/PCMCIA 2.4 GHz User Guide.. H. Xu and B. Bhargava. Reliable Stream Transmission in Mobile Computing Environments. Department of Computer Science, Purdue University, 1995.. [25]. NCR, WavePOINT Installation and Operation Guide. [13]. [14]. [15]. [16]. A. Hills and D. B. Johnson. A wireless data network infrastructure at carnegie mellon university. IEEE Personal Communications, pages 56--63, 1996. R. Caceres and L. Iftode. Improving the performance of reliable transport protocols in mobile computing environments. IEEE Journal on Selected areas in Communications, 13(5):850--857, June 1995.. 16. Guide,.

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(97) DE&@F'GHIJKLM'45NOPQR'5STUV W XYZ[\ ]5^_`a'bc,de01fghi5jklmn' +o5Gpn3qr*+'34/05Js+o-.t`u'vwfCx5gy"i5 z{HIl|}~€~‚ƒ5d„ †56‡ˆm‰1+o'Š‹ŒŽ ‘. All mobile data handsets need to consume battery power. Since battery power is life-limited and should be used efficiently, power consumption is an important issue in mobile data handsets design. This project addresses three mechanisms to reduce battery power consumption for a mobile data handset. A hardware support is needed to achieve the goal, and will be mentioned at the beginning of this paper. Some assumptions required in the modeling work are also given. Then three wake-up methods are described. Finally, analytical and simulation results are provided with some useful guidance on designing power-saving mobile data handsets systems. ’“ A mobile data handset system can be generally divided into three units that consume battery power. They are data receiving, data processing, and user interface units as illustrated in Figure 1. A data receiving unit is a fixed-size memory storage queue for packets received from wireless networks. A data processing unit is a CPU that processes the received data. A user interface unit is in charge of passing the processed data to mobile users. One approach to reduce power consumption is to design a mobile data handset that supplies power separately to the three units. With this design, the data processing and user interface units can be put in the sleep mode while the data receiving unit is waiting for data from the network. Those two units will not be woken up until the data receiving unit receives an incoming packet. A wake-up action is called a switch-on.. OS User Interface Wireless Networks. CPU. Data Receiving. Data Processing. 22. Users. The frequency of switch-on actions performed is defined as the switch-on rate. Once the data processing and user interface units are switched on, they work until the memory queue becomes empty. Then the units enter the sleep mode to conserve power. In sleep mode, only the data receiving unit is awake to receive packets. This handset architecture can be viewed as a single-server queueing system with finite capacity..

(98) Figure 1.. A mobile data handset system. Immediately waking up the data processing and user interface units upon receipt of a packet may cause too many switch-on actions. To avoid this problem, we let the data receiving unit to wait for more packets to arrive before waking up the other two units. To be more specific, a switch-on action is performed only when there has been a certain amount of packets in the memory queue. However, with the continuous arrival of packets, if we do not reserve enough space for the incoming packets, there could be some packets dropped. The probability of a dropped packet that may occur is defined as the packet-dropping probability. We consider three approaches for the switch-on mechanism. In the first approach, a threshold value is used to indicate whether it is time to switch on the system. As soon as the number of packets received reaches the threshold, those two units are woken up to start working. It is important to select the threshold value properly, since any threshold value can affect the switch-on rate and packet-dropping probability at the same time. For convenience, denote the switch-on rate by Rs and packet-dropping probability by Pd. In our second mechanism, the concept of a timer is applied. Every time when the memory queue becomes empty, the server immediately goes for a vacation, and comes back as soon as the vacation time period expires. Sooner or later, the server must finish its vacation and come back to work, so eventually all packets will get served within a finite period of time. Here, how long a vacation should take is worth considering, and will be discussed in this paper. In addition, a hybrid method, combining the strategies of the previous two mechanisms, is proposed as our third mechanism.. 23.

(99) ”ƒ  The state transition diagram for the threshold method: . λ. λ 1*. 0*. λ. .... .... R. µ. µ µ. r-1. µ. λ. r. λ. λ. .... 1. λ. (r-1)*. λ. µ. λ. µ Figure 2.. The threshold method. The state transition diagram for the vacation method:. λ. λ. 0*. 1*. λ 2*. η. η. λ. µ. 1. . R*. η. λ. . 2. µ. λ. µ. η. λ R. µ Figure 3.. The vacation method. The state transition diagram for the hybrid method:. λ 0*. λ 1*. λ 1. µ. .... λ (r-1)*. η. η µ. .... λ. η. λ. λ. λ r. µ. .... µ. λ R. µ. r-1. µ Figure 4.. The hybrid method. How our three mechanisms perform compared with one another is shown in the following figures. When = 0.76, Figure 5 (a) shows the different switch-on rates of the three methods with the 24.

(100) same packet-dropping probability. Clearly, the threshold method has the smallest switch-on rate, while the vacation method claims the highest. Figure 5 (b), however, tells that the vacation method has the lowest mean packet waiting time. Thus, there is no definite judgement to evaluate any method as good or bad. If the system designer cares more about the mean packet waiting time, the vacation method may be adopted regardless of its high switch-on rate. On the contrary, the threshold method is exercised if the switch-on rate is a bigger concern. A moderate alternative is using the hybrid method..        

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(110)     E-mailrhjan@cis.nctu.edu.tw !"#$ %  &'()*+

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(112) K&FGC €"#$ With the popularization of the Internet, we need multicast services more and more. On the other hand, people also desire the computer with high mobility. It is an important question to integrate multicast and mobile system. It has some problems to integrate these two systems in IPv4. Many solutions have been proposed to solve this, but there still have some problems with these solutions. In IPv6, with more elaborate design, it is easier to combine multicast and mobile system. This research is focused on the implementation of integrating the multicast and mobile system.  Multicasting is a technical term that means that you can send a piece of data to multiple sites at the same time. It conserves the scarce bandwidth. Unfortunately, the majority of the routers on the Internet today do not know how to handle multicast packet. For the multicasting experiment some IETF fellow create the MBone. MBone contains islands and tunnels, and it can forward multicast packet from island to island through the tunnel. The main multicast routing protocol on MBone is DVMRP that employs the Reverse Path Multicasting (RPM) algorithm. The main reason of incoordination between Mobile-IP and DVMRP is that the mobile host retains its IP address when it stays on the foreign network where the network address is different from its home network address. When the mobile host sends out a multicast packet not in its home network, the DVMRP router cannot know the packet is originated from the foreign network via the packet’s source address. It will assume the packet is originated from the source address’s home network and make an unpredictable decision – the packet may been discarded even though the situation is not what we want. In IPv6 environment, the Mobile-IPv6 is defined more thoughtful. In Mobile-IPv6, the mobile host must autoconfigure its new address by stateless or stateful mechanism when it moves to foreign networks. No matter what autoconfiguration mechanism is employed, the new IP address is composed of the new network’s address as prefix and the other part as postfix. The mobile host will use this new IP address as its source address in its outgoing packets. This mechanism will solve the 26.

(113) problem we describe above, and we implement the integration of DVMRP and Mobile-IP in IPv6 environment in this research. ‚ƒ„  We have finished Mobile-IPv6 system based on linux environment. The linux kernel version that we developed is 2.1.50. The mobile host can detect movement via the router’s advertisement and send binding message as registration. When the home agent receives the registration, it will intercept packets designated to the mobile host and relay these packets by tunnel. When the mobile host receives the tunnel’s packet, it will send binding update message to the correspondent node. This triggers route optimization on transmission packets from correspondent node to the mobile host. On the other hand, we have finished the base DVMRP router in IPv6 addressing format. This system is based on Windows 95 system. The DVMRP router can implement RPM checking, multicast packet forwarding, routing table maintenance, forwarding cache maintenance, pruning and grafting multicast tree. All the base functions defined in DVMRP version 3 [draft] have been implemented. Now, we devote to integrate and merge these two systems to work well. †‡ˆ‰ Š‹Œ gis86504@cis.nctu.edu.tw Ž gis86517@cis.nctu.edu.tw ‘’ pippen@monet.cis.nctu.edu.tw. 27.

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參考文獻

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