Quality of Service for Multimedia Applications

Quality of Service Provision Assessment for Campus Network Dr., Eur. Ing. Eduard Babulak B.Sc., M.Sc., Ph.D., C.Eng., SMIEEE, MIEE, MBCS, MACM Researcher - Senior Lecturer School of Computing Staffordshire University Stafford ST18 0DG UNITED KINGDOM Web: http://www.soc.staffs.ac.uk/~eb12 September 10-11, 2003

1 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003

by Dr. Eur. Ing. Eduard Babulak PhD C.Eng

Outline of Presentation • • • • •

Introduction CISCO Vision Maximizing Productivity Research Aims and Objectives QoS Definition – QoS View Points – QoS Layered Model

• • • •

Users’ Applications Features Enhanced Disconfirmation Model Determinants of Performance Quality Case Study: Staffordshire University Network – Network Measurements and IT Survey – Discussion of Results

• Conclusions – Question & Answers 2 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


Cisco’s Vision: “Extending the Productivity Zone” 100% 70% 50%

30% 50% 70% 100% SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003

3 by Dr. Eur. Ing. Eduard Babulak PhD C.Eng

Maximizing Productivity Throughout the Workday At Work • Conference rooms • Cafeteria • Temporary cubicle

PSTN

On the Road Internet/Intranet

• Hotels • Airports • Convention centers • Coffee shops • Customer sites

At Home • Telecommuting • Home office 4 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


Cisco Mobile Office—On the Road A global program promoting secure, high-speed access in public venues for mobile professionals—delivered by industry-leading public venues, service providers, and integrator partners Planes, Trains

Customer Sites

Cisco Mobile Office— On the Road Other Venues

Airports

Convention Centers SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003

Hotels by Dr. Eur. Ing. Eduard Babulak PhD C.Eng

5 5

Final Thoughts • Investments in information technology have had significant impacts on organizational productivity and have set the foundation for the networked virtual organization • But the world is changing…and the work environment needs to change to better meet the challenges of the 21st century • Successful organizations will identify ways to extend their employees productivity zones by giving them extended access to the tools necessary to do their jobs 6 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


Current & Future Challenges: Server

• QoS Provision

Real Audio

– Highly Interactive Applications Workstation

• Support Interoperability – Heterogeneous Environments – Open Networking

Camera

Home Video

Network

• Support Integration – Wide range of End devices

Video Title

• CISCO ATM Switch, IP Router with standard interfaces

Disc

– Internet Openness • Attach any network using IP



Introduction • Current methods to assess the QoS provision – What performance is now in the future optimal? – What priority should be assigned to improve performance? – How to assess the user’ perception and network usage? • Identify the University Network Infrastructure – Campuses, Schools and Departments and their mutual links

• Identify basic categories of the University users – Understand the University Network initial Design, etc.,

• Be aware of current and future challenges – – – – –

Network Critical Applications (i.e., payroll, enrolment) Increased number of users and their mobility; More dynamics in traffic and applications; E-commerce and Distance Learning; Students using pattern of IT network • Entertainment and Music files download 8

SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


Research Aim & Objectives • Merger of Engineering and Business Perspectives on QoS Provision in Light of User’s Perception • Enhanced Disconfirmation Model • Network Traffic Measurements • IT Survey

• Suggest Performance Quality Improvements

•

• Determinants of Performance Quality • User’s Applications • Designing High Performance Systems and Scalable Architecture • Congestion Control Techniques New QoS Technologies • Migration to CISCO Technology • Interoperability – Middleware • Session Mobility & Integration 9



The four fundamental QoS viewpoints. Present & Future Value gap

Historic

Current Customer’s QoS Requirements

Alignment gap

Service Provider’s Offered QoS

Network Measurement & Monitoring IT Survey

Customer’s Perceived QoS

Customer

Perception gap

Execution gap

Service Provider’s Achieved QoS

Service Provider 10



QoS Definition • QoS is the ability of network element (e.g. an application, host or router) to have some level of assurance that its traffic and service requirements can be satisfied. • To enable QoS requires the cooperation of all network layers from to-to-bottom, as well as every network element from end-to-end. • Any QoS assurances are only good as the weakest link in the chain between sender and receiver. 11 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


Quality of Service: QoS IT Survey

User Specified QoS

Application Specified QoS Media Quality - Media Relations

20 FRAME/sec - 640X320 PIXELS - 256 COLORS

Transmission and Operating Communications HP System Specified QoS OpenView Quantitative Criteria (throughput, delay, error-rate) Qualitative (synchronization, error recovery, scheduling, etc.)

Network QoS Parameters Requirements on Network Resources

Bandwidth Net. Load (nodal service units) Performance (jitter, cell-loss) Traffic Contract Parameters

Multimedia Devices QoS Timing and throughput demands

Frame-rate

delivery



User Perspective

The QoS Venn diagram

Application Perspective

Response Time

Image size, Color depth Voice quality, Steady picture, etc.

Transmission cost

Delay Jitter

Bandwidth Throughput, Burstiness, Compression, Transport technique

Delay, Jitter, Skew, Error rate

Throughput, Delay. Delay variance, Error rate

Transmission Perspective SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


13

The QoS performance dimensions required by some common applications Performance Dimensions Application

Sensitivity to

Bandwidth Delay

Jitter

Loss

VoIP

Low

High

High

Med

Video Conferencing

High

High

High

Med

Streaming Video on Demand

High

Med

Med

Med

Streaming Audio

Low

Med

Med

Med

E-Business (Web browsing)

Med

Med

Low

High

E-mail

Low

Low

Low

High

File Transfer

Med

Low

Low

High 14



Application Features •

Collaboration across distributed heterogeneous platforms with:

Q o S

– Adaptability • Session mobility – switching between different terminal devices & display resolutions » black & white » color 640x480, 800x600, 1280x1024 or 1600x1200 pixels

– switching between different service providers & locations of servers » reduced latency

– Scalability • An application is scalable if its performance metrics can improve, as necessary and essentially without limit, by adding equipment (more hosts, more network connections, etc) and without the need for replacement of existing equipment. • Further, equipment cost should increase at most linearly with performance metrics, so that the cost per unit measure of performance is Messerschmitt 2000 constant or declines.

– Reliability • System ability to deliver continuous quality service 15 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


P r o v i s i o n

The Enhanced Disconfirmation Model of Customer Satisfaction

Quality = Customer’s Expectation – Customer’s Perception 16 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


Determinants of Performance Quality Factor

Description: Completion time versus throughput

Software The architecture of the application determines the architecture partitioning of the application onto multiple hosts, which determines processing resources. It also addresses the relative location of data and processing. These both impact the communications overhead. Technology

Electronics, magnetic and optical storage, and fiber optics are rapidly advancing. Application performance benefits directly from these technology advances.

Equipment

Computing systems and network exploits technology to provide processing, storage, and communications services to applications. Their performance is determined by both technology and their internal architecture and design.

Messerschmitt 2000



Case Study: Staffordshire University Network • Staffordshire University Campuses on large geographic area – Stoke-on-Trent; Stafford; Litchfield & Adjunct Colleges – Over 18000 university plus adjunct colleges’ users • Students; Academics; Technical & Administrative Staff

– Schools • Arts; Computing; Engineering, Business, etc.

• System Description & IT Architecture – Initial Design (5 years ago) • Simple Hub extended start topology based network • No QoS technology

• Data Collection – Network Measurements & Monitoring • MRTG data collection • HP Probe measurements

– IT Survey Formulation & Administration

• Data Analysis and Result 18 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


Case Study:

Staffordshire Network Architecture





Percentage

Utilization/Total Error 21 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


IT Survey study area of customer perception of QoS



Score Off-campus

3.7

Student residence

4.2

On-campus

5.5

The results of the survey show that the majority of average scores on scale Excellent=10, Very Good=8, Good=6, Reasonable=4, Poor=2, Very poor=0, lie between 4 and 6, indicating that respondents typically see response time lying between reasonable and good, on average. The only exceptions appear to be the use of ftp transactions, which are often seen as less than reasonable, particularly at a student residence or at home. 23 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


Correlation studies • There was a correlation between the user’s perception and the overall network utilization – With the increased level of utilization the user’s satisfaction is decreasing.

• The measurements suggest that the half-duplex network utilization was 70%; • The users’ perception was within the limits of reasonable and good; 24 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


Conclusions I

• Discussion of : – – – – – –

Research Aims and Objectives QoS Fundamentals Users’ Applications Features Enhanced Disconfirmation Model Determinants of Performance Quality Case Study: Staffordshire University Network • Network Measurements and IT Survey • Discussion of Results 25



Conclusions II

• Recommendation to IT Services: – The effective use of new QoS Technology • ATM, RSVP network architectures with capacity assignments based on application and transport level QoS parameters. • Implement more dynamic QoS provision technology – Session Mobility

– Apply more effective network monitoring policies • Proactive Measurements policies • Students Access Practices • Network Security, Convergence and Adaptability

– Maintaining users’ satisfaction • Competitive edge • Cost effectiveness 26 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


THANK YOU ANY QUESTIONS? 27 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


Designing High Performance Systems and Scalable Architecture • • • •

•

•

Break the application down into small, atomic tasks, where each task will be assigned to one host (to avoid communication overhead. Characterize the resource requirements of each task. For example, how much processor execution time and memory and storage space does it consume? Analyse the communication pattern among tasks and in particular the communication burden on the network created by assigning tasks to different hosts. Understand the scheduling constrains on the task. What task depends on the prior completion of others (i.e., parallelism, scheduling?) In light of these constraints, tentatively assign tasks to different hosts in a way that attempts to achieve the maximum parallelism and minimizes communication requirements. Tasks prioritisation for what task should be completed at what host most urgently to reduce the communications overhead. Analyse the proposed host assignment in terms of hot spots to points of congestion in either processing or communication, as well as, under-utilised resources. What bottlenecks will ultimately limit overall application performance (i.e., response time to users)? 28



Messerschmitt 2000

Congestion Control Implementation Techniques Approach

Description

Source Initiated

Sources detect network congestion, or are informed by the network (directly or through pricing), and limit the offered traffic. This has the advantage that sources can offer the most compelling traffic or shift less compelling traffic to another time.

Network Policing

The network enforces limits on the traffic it will accept from each source. The network may engage in flow control with each source, or it may silently drop excess traffic.

Messerschmitt 2000



IT Network Current Developments • New 34 Mbps Automatic-Fail-Over resilient link was added in parallel to the ATM 622 Mbps link between Stafford and Stoke campuses to deal with heavy traffic. • There is a proposed 34 Mbps circuit between Stoke and Lichfield site as well for the year 2003. • The E-mail server sits on very powerful Mellor 5509 switch in Stoke – Switch Octagon 5509 has CISCO Interconnection Operating System (IOS) version 12 installed with fast Ethernet port and Gigabit uplink services.

• The Web-server configuration on the Octagon 5509 switch and the web-cache is in Stoke • Use of the “H drive” to store the students’ scholarly files.



The IT Measurements Policies: • Reactive (i.e. ad-hoc proactive activities): Old policies – This is due to the lack of personnel training for using exploiting the technology to its maximum.

• Active: New Policies – The Packeteer implementation purely on RESNET only starting from September 2002, which is very active measurement of the type of traffic at student residencies • Due to high volume of complaints about slow ftp service due to the fact that more than 50 % of traffic was generated by the Audio-galaxy music files transfers. • The packeteer solution will help to identify and to shape the traffic accordingly in order to give higher priorities to the work related type of traffic (i.e., ftp, file sharing) instead of the entertainment type of traffic (music, games, etc.)

• New DHCP implementation requiring all the users to register their MAC addresses from the DHCP in order to be allowed to get the dynamic IP address required connect to the IT network. 31 SimpoTIC’03 BRATISLAVA OCTOBER 26-28, 2003


Discussion: Different QoS Technologies QoS Monitoring and Management

ApplicationSignaled QoS

RSVP

IP QoS

IP Differentiated Services (DiffServ)

NetworkSignaled QoS

ATM, PNNI, MPLS RSVP-TE or MPLS CR-LDP

Traffic Engineered Path

ATM PVCs, MPLS Lable Switched Path (LSPs)

Link Layer QoS

Ethernet 801p, VLAN, ATM, MPLS, PPP, UMTS, DOCSIS, Frame Relay

Physical QoS

Wavelengths, Virtual Circuits (VCs), Ports, Frequencies

Layer



Discussion: IT Survey Results Campus Base Usage Frequencies

Respondent Type Frequency Percent Academic Staff

58

12.5

Clerical/Admin Staff

29

6.3

Management Staff

21

4.5

328

70.8

27

5.8

463

100.0

Student

Technical Staff Total

Frequency Percent Litchfield

31

6.7

Other

12

2.6

Stafford

277

59.8

Stoke-onTrent

143

30.9

Total

463

100.0



Diagram representing the common usage of IT network

450 400 350 300 250 200 150 100 50 0

Usage Main usage

Univ campus

Student Res

Home 34



Remote Connections 160 140 120 100 80 60 40 20 0 128K Modem

56K Modem

ADSL

DSL

ISDN



Type of Operating System

Number

Window s NT

Window s 2000

Window s 95

Linux 0

20

40

60

80

100

120

140



Daily Usage Pattern 350 300 250 200 150 100 50 0 12-3am 3-6am

6-9am

912-3pm 3-6pm 12noon

6-9pm 9pm-12



User’s Session Duration Frequency More than two hours

Percent 199

44.1

Up to 10 minutes

12

2.7

Up to 30 minutes

38

8.4

Up to one hour

101

22.4

Up to two hours

101

22.4

Total

451

100.0



Respondent Application Usage admin app

email First use Usage web

ftp

0

20

40

60

80

Percentage



User’s Perception of the Application Performance Campus

Student Residence

Home

Last use

5.1

4.4

4.4

ftp

4.0

2.8

3.3

Web

4.8

5.4

4.3

Email

5.5

5.4

4.6

Admin

5.0

4.1

