Course Project Book(Mobile Computing and Wireless Networks)

CS 395T – Spring 2001

Course Instructor:Dr. Yongguang Zhang (ygz@cs.utexas.edu)

Course URL: http://www.cs.utexas.edu/users/ygz/395T

May 16, 2001

Project List

1. Mobile IP service for ACES and TAY2. Location Service for Mobile Device3. Linux Kernel Support for Ad-hoc Routing4. Linux Kernel Module for Ad-hoc Routing5. Multi-Mode TCP for Wireless Networks6. Equation-Based TCP Window Adjustment7. TCP Performance for Ad Hoc Networks8. Ad Hoc IP Routing over Bluetooth Scatternets9. Scalable DNS for Mobile Computing10. Active Ad Hoc Networking11. Energy-Aware Routing in Ad Hoc Networks12. Transparent Migration of Mobile Agents13. Service Discovery in Wireless Networks

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

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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 802.11 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:–802.11 does not have good support for mobile

IP smooth handoff in infrastructure mode.–No easy heuristics to determine network

change (layer2) in 802.11 access point mode.

Project team: Madhusudan Kayastha, John ThomasURL: http://www.cs.utexas.edu/users/john/mobileIP.html

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

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Key Design/Approach Data collation: mapping the service area in

advance for an accurate signal map Algorithm 1: best matching: O(n2) Algorithm 2: multidimensional search

O(log(n)) GUI (see above) Limitation : Placement of Base stations

limited to certain locations

New Ideas Increasing proliferation of 802.11 base

stations and PC card use 802.11 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 6th floor

–Beacon stations: 2–Service granularity: 10 feet

Accuracy: 90% of the time: within 15 feet Lesson learned:

–802.11 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 NapperURL: http://www.cs.utexas.edu/users/ravshank/mobile_project/project.html

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

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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 comm’n. 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 2.4.3

– 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 JainURL: http://www.cs.utexas.edu/users/puneet/mobcomp/proposal.html

AKM:Ad-hoc Kernel ModuleAUD: Ad-hoc User DaemonART: Ad-hoc Routing Table

NIM: Network Interface ModuleUIM: User Interface Module

Linux Kernel Support for Ad-hoc Routing

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

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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 ShilotriURL: http://www.cs.utexas.edu/users/liwei/AdHoc/

Linux Kernel Module for Ad-hoc Routing

A CS395T Course Project MobileComputing &

WirelessNetworks

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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 TianURL: http://www.cs.utexas.edu/users/ftu//project.html

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

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

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Design Objective: fast estimation of congestion

window size–Node i keeps its own congestion loss rate pi

–TCP packet has an additional field, FP (Forwarding Probability).

–FP is initially set to 1 , and multiplied by 1-pi 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 doesn’t 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 JungURL: http://www.cs.utexas.edu/users/minskim/mobile/

Equation-Based TCP Window Adjustment

3p/2/1cwnd

Results 1

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

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• Instructo

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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 LinURL: http://www.cs.utexas.edu/users/wangf/manetcp.htm

TCP Performance for Ad Hoc Networks

Results Conclusion DSR and DSDV is the best AODV is not as good TORA is far worst

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

ourse

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: http://w

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• Instructo

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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 RastogiURL: http://www.cs.utexas.edu/users/sidharth/report

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

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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 SohnURL: http://www.cs.utexas.edu/users/bongbong/mobile

Motivation Using DNS as location service

infrastructure for mobile computing

Dynamic updates are already defined in RFCs

No caching? Scalability?

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

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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 ShannonURL: http://www.ece.utexas.edu/~shannon/CS395T.htm

PLAN

PLAN

DSR AODV

TORA

Active (FastNet) Node

DSR

TORA

AODV

TORA

Code Pushing

Remote Evaluation

DSR

AODV

Active (FastNet) Node

Active (FastNet) Node

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

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• Instructo

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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 YangURL: http://www.ece.utexas.edu/~yangxy/395T.htm

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

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

ourse

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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. AdduriURL: http://www.cs.utexas.edu/users/endisd/mobile

agent source code

agent byte-code

agent byte-codewith supportfor mobility

javac

parser

server

agents

transparentmigrationwith RMI

A CS395T Course Project MobileComputing &

WirelessNetworks

Spring 2001C

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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 SharmaURL: http://www.ece.utexas.edu/~arifler/CS395T/index.htm

Multimedia Provider

Java-based Client GUI

Microsoft Access

Lookup Service

Multicast in a Jini-enabled wireless network

SQL, JDBC

Service URL

Contact

Prof. Yongguang ZhangDept. of Computer SciencesUniversity of Texas at AustinAustin, Texas 78712, U.S.A.

E-mail: ygz@cs.utexas.eduPhone: 512-232-7889