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Network Research at CDMNetwork Research at CDM

James Yu, Ph.D.James Yu, Ph.D.Associate ProfessorAssociate ProfessorSchool of ComputingSchool of Computingjyu@cdm.depaul.edujyu@cdm.depaul.edu

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James Yu, Ph.D.James Yu, Ph.D.

Ph.D. in Computer Science from Purdue Ph.D. in Computer Science from Purdue University, 1985University, 1985[Distinguished] Member of Technical Staff, [Distinguished] Member of Technical Staff, Bell Labs, Lucent Technologies, 1985 – Bell Labs, Lucent Technologies, 1985 – 20002000Director of Network Technologies, Director of Network Technologies, ARBROS Communications, 2000 – 2001ARBROS Communications, 2000 – 2001Assistant/Associate Professor, DePaul Assistant/Associate Professor, DePaul University, 2002 - nowUniversity, 2002 - now

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Research InterestsResearch Interests

Wireless SecurityWireless Security

VoIP Traffic EngineeringVoIP Traffic Engineering

Network ManagementNetwork Management

Fault Tolerant Network DesignFault Tolerant Network Design

Network education: hands-on exercises Network education: hands-on exercises for distance learning studentsfor distance learning students

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Framework of Network Research (I)Framework of Network Research (I)Problem

Statement

EmpiricalFramework

TheoreticalModel

Data Analysis

Solutions to The problemR

efer

ence

s

ComparativeStudy Conclusion

Revision

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Framework of Network Research (II)Framework of Network Research (II)Problem

Statement

EmpiricalFramework

TheoreticalModel

Solutions to The problem

ComparativeStudy

Conclusion

Data AnalysisData Analysis

Your solution must be theoretical sound along with empirical support.

Problem StatementProblem StatementIs the problem Is the problem significantsignificant and and interestinginteresting??– References, References, ReferencesReferences, References, References

Can you describe the problem in one or Can you describe the problem in one or two sentences?two sentences?

Can you describe the problems with Can you describe the problems with numbersnumbers??

Is the problem solvable?Is the problem solvable?

Is the problem already solved?Is the problem already solved?

Do not confuse the problem with the Do not confuse the problem with the solution.solution.

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MeasurementMeasurement

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“When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be." [Lord Kelvin, PLA, vol. 1, "Electrical Units of Measurement", 1883-05-03]

Dependent Variable(s) Dependent Variable(s) vs.vs.

Independent VariablesIndependent Variables

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Y = F (X1, X2, X3, …..)

Review of Research PaperReview of Research Paper1-2 page of each paper you read1-2 page of each paper you read

Problem StatementProblem Statement

Results and Major ConclusionsResults and Major Conclusions

Research Methodology (empirical or Research Methodology (empirical or theoretical)theoretical)

Comparison with other research workComparison with other research work

Your assessmentYour assessment

Can you reproduce the research results?Can you reproduce the research results?

Can you improve the research results?Can you improve the research results?

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NETWORK RESEARCH NETWORK RESEARCH PROJECTSPROJECTS

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TransportNetwork

SwitchedNetwork

NetworkServices and Management

Acce

ssN

etw

ork

DataCenter

CallCenter

DataLAN

VoiceNetwork

2G/3GNetwork

ISPNetwork

PSTN

Internet

carrier network

converged enterprise networkcellular network

Security Layer

Secu

rity

Layer

Network: the BIG Picture

Security Layer

UNI

NNI

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Project I: Performance AnalysisProject I: Performance AnalysisKey measurement: throughput (bps) and delay (ms or s)

Ethernet Switch

IP Router

LinuxBridge/Router

WindowsBridge/Router

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Switch Performance ComparisonSwitch Performance Comparisonon Gigabit Etherneton Gigabit Ethernet

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

Switch Linux Windows

100M

1000M

Question: could you develop a problem statement from this chart?

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Wireless Performance Wireless Performance

0

10

20

30

40

50

60

802.11b 802.11g

Line Speed

UDP

TCP

Question: why is TCP performance is only 50% of the line rate for wireless communications?

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Project II: Wireless Denial of Project II: Wireless Denial of Service (DoS) ResearchService (DoS) Research

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TCP performance under DoSTCP performance under DoS

Start Stop

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Project III: VoIP ResearchProject III: VoIP Research

PSTN Switch

SS7

IP (public)

Trunk MG

SoftSwitch

SS7

IP (private)

IP (internal)

PSTN Switc

h

Access MG

Call Manager(SIP Proxy)

SoftSwitch

V V V V Call Manager(Enterprise)

Trunk MG

Q.931

MG: Media Gateway

Carrier VoIPNetwork

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VoIP: Traffic EngineeringVoIP: Traffic Engineering

Design the network with sufficient capacity to meet Design the network with sufficient capacity to meet the traffic demand with satisfactory performancethe traffic demand with satisfactory performanceRequirement: assurance of Voice Quality.Requirement: assurance of Voice Quality.– If call quality cannot be assured, reject the call request.If call quality cannot be assured, reject the call request.

Demand (A) - Traffic Intensity Demand (A) - Traffic Intensity number of calls × duration of average callsnumber of calls × duration of average calls

ErlangErlangResources (N) – Network bandwidth (bps) and Resources (N) – Network bandwidth (bps) and capacity (pps)capacity (pps)Grade of Service (GoS) – blocking probabilityGrade of Service (GoS) – blocking probability

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Research Areas of VoIPResearch Areas of VoIP

IP Multimedia Subsystem (IMS)IP Multimedia Subsystem (IMS)– How is a VoIP call from one service provider to How is a VoIP call from one service provider to

another service provider today?another service provider today?

VoIP SecurityVoIP SecurityVoice QualityVoice QualityQuality of Service (QoS) over internet and Quality of Service (QoS) over internet and intranetintranetSupplemental and Intelligent Network (IN) Supplemental and Intelligent Network (IN) servicesservicesAPI and VoXMLAPI and VoXML

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Project IV: Fault Tolerant NetworkProject IV: Fault Tolerant Network

ISP-01

ISP-02

Dual HomingVRRPRSTP (802.1w)RSL

Network Design Goal:1. No single point of failure2. Failover time << 1 sec

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Project V: Remote Lab Access Project V: Remote Lab Access

PublicInternet

PrivateNetworking

Labs

LinuxGateway

WindowsTerminal Server

TelecomTerminal ServerConsole

interface

Devices w/IP

interface

Devices w/Console interface

Problem Statement: supporting distance learning students to perform hands-on network exercises from any place with 24×7 access to the network lab

Research on Networking Research on Networking EducationEducation

Does the DL environment support the same Does the DL environment support the same learning goals effectively as the in-class learning goals effectively as the in-class students?students?– How do you define and measure the How do you define and measure the

conformance to the learning goals and the conformance to the learning goals and the effectiveness of the learning environment?effectiveness of the learning environment?

Does multiple choice questions measure the Does multiple choice questions measure the learning as effective as other methods?learning as effective as other methods?

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Project VI: Network ManagementProject VI: Network Management

Command-Oriented

Object-Oriented

Document-Oriented

Variable-Oriented

Transaction-Oriented

Vendor specific

SNMP/MIB

CORBA

XML-Based

NETCONFNETCONF

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NETCONFNETCONFA new Protocol from IETFA new Protocol from IETFIt is designed to address many current issues of network It is designed to address many current issues of network mangement.mangement.

XML-based and Transaction-BasedXML-based and Transaction-Based– The XML standard is well defined The XML standard is well defined – The XML Schema allows flexible definition of the The XML Schema allows flexible definition of the

structured management information structured management information – download/upload of complete device configuration download/upload of complete device configuration – human-readable human-readable – cost-effective to develop new applications and cost-effective to develop new applications and

servicesservices

Integration with security infrastructureIntegration with security infrastructureOpen issue – a lack of data modelsOpen issue – a lack of data models

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Research DeliverablesResearch DeliverablesNo deliverables; no researchNo deliverables; no research

Publications, Publications, PublicationsPublications, Publications, Publications– Journal Papers – only if acceptedJournal Papers – only if accepted– Conference PapersConference Papers– Technical Reports (little weight)Technical Reports (little weight)– Grant proposals – only if awardedGrant proposals – only if awarded– Whitepapers? (does not count)Whitepapers? (does not count)

Tools, Demo, etc – good only if you have Tools, Demo, etc – good only if you have publications associated with them.publications associated with them.

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Technical WritingsTechnical WritingsIt is more important than your technical It is more important than your technical capabilities. Actually, it is a lot more capabilities. Actually, it is a lot more important.important.

Take a technical writing course if you have Take a technical writing course if you have never taken one.never taken one.

use the DePaul Writing Labsuse the DePaul Writing Labs

William Strunk Jr. the Element of StyleWilliam Strunk Jr. the Element of Style

Yes, we are very picky (and extremely Yes, we are very picky (and extremely picky)picky)

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RecommendationsRecommendationsThere is no shortcut for research.There is no shortcut for research.Your approach may not work. Actually, it is not likely Your approach may not work. Actually, it is not likely to work most of the time, but do not give up.to work most of the time, but do not give up.You may find an elegant solution if you redefine the You may find an elegant solution if you redefine the problem. Be flexible.problem. Be flexible.If this is your 1If this is your 1stst or 2 or 2ndnd year, you may try to reproduce year, you may try to reproduce with minor refinement of others research work. with minor refinement of others research work.Be in a research team. If not, keep regular contact Be in a research team. If not, keep regular contact and discussion with other Ph.D. students. Build your and discussion with other Ph.D. students. Build your community now (CSC426)community now (CSC426)It is easier to publish at SoCRS and you should do it.It is easier to publish at SoCRS and you should do it.