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Course Project Book (Mobile Computing and Wireless Networks) CS 395T – Spring 2001 Course Instructor: Dr. Yongguang Zhang Course URL:

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Presentation on theme: "Course Project Book (Mobile Computing and Wireless Networks) CS 395T – Spring 2001 Course Instructor: Dr. Yongguang Zhang Course URL:"— Presentation transcript:

1 Course Project Book (Mobile Computing and Wireless Networks) CS 395T – Spring 2001 Course Instructor: Dr. Yongguang Zhang Course URL: May 16, 2001

2 Project List 1.Mobile IP service for ACES and TAY 2.Location Service for Mobile Device 3.Linux Kernel Support for Ad-hoc Routing 4.Linux Kernel Module for Ad-hoc Routing 5.Multi-Mode TCP for Wireless Networks 6.Equation-Based TCP Window Adjustment 7.TCP Performance for Ad Hoc Networks 8.Ad Hoc IP Routing over Bluetooth Scatternets 9.Scalable DNS for Mobile Computing 10.Active Ad Hoc Networking 11.Energy-Aware Routing in Ad Hoc Networks 12.Transparent Migration of Mobile Agents 13.Service Discovery in Wireless Networks

3 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Project Goals Implement & deploy of Mobile IP in CS Network. Determining best location for home agent and foreign agent. Study best mode of operation for mobile node (co-located COA or FA assigned COA) to achieve smooth handoff. Auto configuration of mobile node when network change is detected. New Ideas Achieving smooth handoff while roaming between different wireless LANs operated in infrastructure point mode using mobile IP. Algorithm to determine change of network –Guessing the network change based on three missed beacon (registration request). –Guessing network change based on signal strength –Based on users input Mobile IP service for ACES and TAY Results/Lesson Learned Experimental Mobile IP is operational in CS Network Our Algorithm helped to achieve semi- smooth handoff while moving between ACES and TAY wireless network (30 sec approx). Lesson learned: – does not have good support for mobile IP smooth handoff in infrastructure mode. –No easy heuristics to determine network change (layer2) in access point mode. Project team: Madhusudan Kayastha, John Thomas URL:

4 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Key Design/Approach Data collation: mapping the service area in advance for an accurate signal map Algorithm 1: best matching: O(n 2 ) Algorithm 2: multidimensional search O(log(n)) GUI (see above) Limitation : Placement of Base stations limited to certain locations New Ideas Increasing proliferation of base stations and PC card use wireless LAN infrastructure to determine mobile device location inside building Signal strength can be measured and there is a correlation between signal strength and distance Signal strengths from multiple base stations can triangulate the exact location Location Service for Mobile Device Results/Lesson Learned Implemented in Linux Tested in ACES 6 th floor –Beacon stations: 2 –Service granularity: 10 feet Accuracy: 90% of the time: within 15 feet Lesson learned: – Linux driver does not support promiscuous mode to pick up beacons from multiple base stations –Resolved to ad-hoc mode Project team: Ravishankar Chamarajnagar, Jeff Napper URL:

5 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Design Generic Interface for all ad-hoc routing protocols – Network Interface Module (NIM) – User Interface Module (UIM) NIM: Interface to Network Stack AKM: In Data Plane – Forwarding according to Ad-hoc protocol UIM: for data and control plane commn. AUD: In Control Plane – Ad-hoc Route maintenance New Ideas Many Ad-hoc Routing Protocols Exist Very few real implementations – High Complexity – Not enough tools for development – Performance claims based on simulation results Designed and developed a generic infrastructure – Provides a tool to evaluate Ad-hoc protocols Implementation & Testing Implemented in Linux – Used Netfilter & IPTable support Tested multihop routing –Three hosts in broadcast setup Test Protocols: – Manual Configuration – AODV Can be extended to support multiple protocols simultaneously Project team: Puneet Chopra, Sumit Garg, Sugat Jain URL: AKM:Ad-hoc Kernel Module AUD: Ad-hoc User Daemon ART: Ad-hoc Routing Table NIM: Network Interface Module UIM: User Interface Module Linux Kernel Support for Ad-hoc Routing

6 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Design Function separation between user and kernel; Necessary communication overload between user and kernel are reduced to minimum; New Ideas Provide an architecture for ad hoc routing protocol implementation by extracting the common part, like multihop for packet delivery, reliable link layer maintenance, etc into general kernel module. Implementation & Testing Kernel on top of Linux 2.4.2; Two hosts can talk to each other; Communication between user and kernel are tested; AODV user daemon implemented Other protocol implementation are extendable Project team: Zhenxun Xiao, Wei Li, Minesh Shilotri URL: Linux Kernel Module for Ad-hoc Routing

7 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Key Design/Approach A mode includes cwnd, ssthresh, rtt, srtt, rttvar, rtxcur, etc. Generally, save the current mode and load a new mode for a vertical handoff Schedule a handoff timer for a downward handoff to avoid fast retransmission caused by out-of-order delivery Reset mode for an upward handoff to an unvisited overlay network An extension to New-reno TCP New Ideas TCP manages multiple modes A mode is a subset of entire TCP state – corresponds to an overlay network – dynamic TCP is notified of the handoff events TCP switches between modes when the mobile host vertical handoffs between different overlay networks Different actions for upward and downward handoffs Multi-Mode TCP for Wireless Networks Results/Lesson Learned Implemented in ns2 Simulation results in ns2 –Eliminate unnecessary retransmissions caused by timeouts or duplicate acks –TCP goodput improved (> 7%) Lesson learned: – Implementation of TCP stack – Limitation of the simulation – Need of more realistic experiments Project team: Fengfeng Tu, Hongxia Tian URL: Motivation TCP has been tuned to traditional networks comprising wired links and stationary hosts Wireless overlay networks – Heterogeneous overlays – User mobility: vertical handoffs – Sudden, frequent, and significant changes in bandwidth and delay Study TCP behavior over wireless overlay networks and improve its performance

8 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Design Objective: fast estimation of congestion window size –Node i keeps its own congestion loss rate p i –TCP packet has an additional field, FP (Forwarding Probability). –FP is initially set to 1, and multiplied by 1-p i at each intermediate node i. –Receiver reports FP to the sender with ACK. –Congestion window is calculated from the path loss rate p = 1-FP: Problem Packet corruption caused by wireless transmission –Caching and retransmission at base station. –Each node in ad hoc network doesnt have enough resource. Link failure due to mobility –Explicit notification freeze TCP states until new route found. –Old states may not be appropriate for new route. Results 2 Project team: Min Sik Kim, Eunjin Jung URL: Equation-Based TCP Window Adjustment Results 1

9 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Simulation Setup Using NS2 –20 mobile nodes –500x500 grid –6 different levels of moving speed –Single and multiple connections traffic pattern Problem What is the performance of TCP over an ad hoc network, under each of the four ad hoc network routing protocols? –DSR –AODV –DSDV –TORA Project team: Feng Wang, Zhiwei Lin URL: TCP Performance for Ad Hoc Networks ResultsConclusion DSR and DSDV is the best AODV is not as good TORA is far worst

10 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Key Design/Approach IP networking for bluetooth scatternet –Piconet bridging scheme –Each scatternet as one IP network –Host based addressing Master Relay Switch Routing (MRSR) –Ad-hoc routing in scatternet –based on AODV New Ideas A new architecture for IP networking in bluetooth scatternet –Current standard (LAN profile, BNEP) does not tackle inter-piconet IP networking issue Cluster-based on-demand routing strategy –Master Relay Switch Routing (MRSR) protocol for inter-piconet IP forwarding Ad Hoc IP Routing over Bluetooth Scatternets Results/Lesson Learned Implemented in NS2 Extension to IBM BlueHoc Project team: Sidharth Choudhury, Anupam Rastogi URL:

11 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Key Design/Approach DNS Workload Analysis 4.5% in number, 0.8% in bandwidth 80% absorbed at client cache 70% absorbed at name servers 94% absorbed by cache –Problem if no cache Scalable DNS for Mobile Computing Results/Lesson Learned Importance of smart caching scheme Scalability of DNS can be achieved from server replication. Update individual hosts instead of zones Project team: Dong-Young Lee, Bong-Soo Sohn URL: Motivation Using DNS as location service infrastructure for mobile computing Dynamic updates are already defined in RFCs No caching? Scalability?

12 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Key Design / Approach DSR(basic, optimized, multipath), AODV, and TORA protocols implemented –Node Resident Service functions for basic protocol operations (coded in Popcorn) –Protocols (really mobile glue code) implemented in PLAN Dynamic Linking of protocol modules Limitation: –Due to lack of concurrency in FASTNet, only Route Discovery protocol is implemented. Route Maintenance is emulated. New Ideas Dynamic Ad Hoc Routing Protocols implemented in an active networking test- bed Dynamic Protocol Dissemination using mobile code Provides Increased adaptability to unpredictable Ad Hoc environment Active Ad Hoc Networking Results / Lessons Learned Implemented in FASTNet & PLAN (Linux) Choose routing protocols adaptively. Lessons learned: –AN can provide dynamic & efficient routing protocols for MANET –Decision-making mechanism for optimal protocol in each environment is needed –Need to extend this idea in test-bed system Project team: Seong-Kyu Song, Stephen Shannon URL: PLAN DSR AODV TORA Active (FastNet) Node DSR TORA AODV TORA Code Pushing Remote Evaluation DSR AODV Active (FastNet) Node

13 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Simulation Setup Single source-destination pair without node mobility Single source-destination pair with node mobility Multiple source-destination pairs without node mobility Multiple source-destination pairs with node mobility Introduction of energy balance factor which represents the heterogeneity of initial energy level at each node Routing Algorithms Maxmin routing algorithm – choose the path whose minimum energy level node has the maximum value among all paths. Maxmax routing algorithm – choose the path which has maximal residual energy on the path Maxavg routing algorithm – choose the path which has maximal average energy level Shortest path routing algorithm – no energy consideration Energy-Aware Routing in Ad Hoc Networks Results/Lesson Learned Overall our Maxmin algorithm performs well. One example of results: Project team: Jangwon Lee & Xiangying Yang URL: Motivation Mobile nodes are battery-operated and one or several nodes energy exhaustion may cause the disruption of the entire network A number of approaches focus on minimizing the total consumed power. Several approaches goal was to maximize the life time of the system. However, these are based on static topology and given traffic demands in advance. Our goal is to propose energy-aware routing algorithms in dynamic ad hoc network environments to achieve max. system lifetime. Simulation techniques such as generating topology and random traffic etc. Obtain a research trend of energy-aware design in mobile computing environments

14 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Design/Approach Provide a Java mobile agent system that supports transparent migration Use standard JVM to gain better acceptance Use byte-code instead of source code New Ideas Transform mobile agent byte-code to support transparent migration Simulate thread and stack frame to support saving and restoring call stack and local variables Mechanism for surviving migration failure which provides more reliable disconnected operation Transparent Migration of Mobile Agents Results/Lesson Learned Developed API, parser, and server for mobile agent programming and deployment With transparent migration, mobile agent programming is more intuitive Demonstrate typical mobile agents applications using our framework Project team: Endi S. Dewata, Kiran K. Adduri URL: agent source code agent byte-code with support for mobility javac parser server agents transparent migration with RMI

15 A CS395T Course Project Mobile Computing & Wireless Networks Spring 2001 Course web site: Instructor: Dr. Yongguang Zhang Key Design / Approach Component-based technologies. Multimedia Services Application: –Multimedia Client: Plays multimedia files from Service URLs using JMF. –Multimedia Service Provider: Provides Service URLs to clients, interfaces to user database. –Reggie (The Service Lookup by Sun Microsystems): Keeps track of available services. –User Database (Microsoft Access connected to Service Provider via ODBC and JDBC) New Ideas A Jini-based Multimedia Services Application designed for ad hoc wireless systems. Use of multicast-based service discovery protocols for multimedia services in ad hoc wireless networks. –Adapt to changes in bandwidth in wireless overlay networks. –Provide value-added services to roaming users with minimal configuration. Integrated user accountability for services. Service Discovery in Wireless Networks Results / Lessons Learned Service discovery is crucial in emerging packet-based wireless technologies (3G/4G, Bluetooth) Lessons learned: –Holding users accountable for using wireless bandwidth for value-added services is necessary. –Key challenge: Integrating various enabling technologies (Jini, JMF, JDBC, etc.) Project team: Dogu Arifler, Vivek Sharma URL: Multimedia Provider Java-based Client GUI Microsoft Access Lookup Service Multicast in a Jini-enabled wireless network SQL, JDBC Service URL

16 Contact Prof. Yongguang Zhang Dept. of Computer Sciences University of Texas at Austin Austin, Texas 78712, U.S.A. Phone:


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