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Institute of Computer Science Department of Distributed Systems Prof. Dr.-Ing. P. Tran-Gia QoEWeb: Quality of Experience and User Behaviour Modelling for.

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Presentation on theme: "Institute of Computer Science Department of Distributed Systems Prof. Dr.-Ing. P. Tran-Gia QoEWeb: Quality of Experience and User Behaviour Modelling for."— Presentation transcript:

1 Institute of Computer Science Department of Distributed Systems Prof. Dr.-Ing. P. Tran-Gia QoEWeb: Quality of Experience and User Behaviour Modelling for Web Traffic Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de

2 2 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Partner  University of Würzburg Tobias Hoßfeld, Daniel Schlosser, Thomas Zinner, Valentin Burger  Blekinge Institute of Technology Markus Fiedler, Patrik Arlos, Junaid Shaikh  France Telecom SA Sergio Beker, Denis Collange, Frédéric Guyard, Frédérique Millo  Warsaw University of Technology Zbigniew Kotulski, Wojciech Mazurczyk, Tomasz Ciszkowski  http://www3.informatik.uni-wuerzburg.de/research/projects/qoeweb/

3 3 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Motivation  User behavior strongly influences systems  e.g. selfishness, churn, or pollution in P2P systems  time-based or volume-based models in shared systems  But, current web traffic models do not consider QoE / user behavior / impatience !  Derive QoE and user behavior model for web traffic based on  active measurements in a laboratory test  passive measurements within an operator’s network  Apply model and evaluate its impact on selected examples  wireless networks with shared capacity  reputation management to react before the user reacts

4 4 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Agenda  Impact of User Behavior  Example: rate control in UMTS  Active and passive measurements  QoE and User Behaviour Modelling for Web Traffic  non-linear interdependency between QoE and QoS  timely behavior  Reputation Management  Work plan

5 5 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Example: Rate Control in UMTS Systems  Best-effort user and QoS user with guaranteed bandwidth  Time- and volume-based user: e.g. voice calls and FTP user  Impact of user behavior on performance of system? Transmission Power for QoS user?  Rate for BE user! BS x Time Transmission Power for QoS1 QoS1 QoS2 QoS4 QoS3 BE3 BE1 BE2 Transmission Power for BE3 Constant Transmission Power for DPCCH

6 6 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de A Priori Source Traffic Model of a Web User Viewing Time V Web Page WWW Session InterSessionTime I Inline Object GetReq. TCP 1 TCP 2 TCP 3 TCP 4 GetReq. Inline Object Inline Object GetReq.Inline Object Inline Object GetReq. Inline Object Main Object GetReq. Web Page Number X of Web Pages GetReq. Volume R of GetRequest Volume M of Main Object Volume O of Inline Object Number N of Inline Objects N

7 7 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Simulation: Web Users in Rate-Controlled UMTS  Different conclusions according to user behaviour model  volume-based users: rate control degenerates?!  time-based users: rate control works as expected?!  Important to get realistic models volume-based userstime-based users web users rate decreases duration of session increases number of users increases

8 8 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Basic Queueing Theory  Birth-Death-Model  Time-based users  Volume-based users 0 µ0µ0 1 λλ µ1µ1 M(1)-1M(1)M(1)+1 λλλλ µ M(1)-1 µ M(1) µ M(1)+1 µ M(1)+2 n-1n λλ µ n-1 µnµn Basic queueing theory leads to same qualitative results  understanding of system behavior  will be applied in QoEWeb

9 9 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Agenda  Impact of User Behavior  Example: rate control in UMTS  Active and passive measurements  QoE and User Behaviour Modelling for Web Traffic  non-linear interdependency between QoE and QoS  timely behavior  Reputation Management  Work plan

10 10 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Objectives of Measurements  Active measurements  quantification of user impatience due to bad network conditions  quantification of the decrease of satisfaction as a function of time or actions  disturb QoS in laboratory environment  user survey  can also be applied to interpret passive measurements  Passive measurements  investigate the statistical behavior of web traffic  analyze the correlations between the behavior of users and some network performance metrics

11 11 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Passive Measurements: Traffic Modeling  Daily behavior  Typical hours  Model of web transfers / sessions  Traffic metrics: up/down volume, type of end  Network performance criteria: throughput, loss rate, RTT  Application level performance: response time, cancelled downloads  Type of web transfers with similar characteristics  Aggregation in sessions (threshold ?)  Type of web servers  Influence of the hourly variations  Model the behavior of web users, typology

12 12 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Analysis of Correlations  Correlation between traffic metrics and performance criteria  For web transfers / sessions / users  significant performance criteria, dependence function according to  the type of transfer / session  the type of users

13 13 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Agenda  Impact of User Behavior  Example: rate control in UMTS  Active and passive measurements  QoE and User Behaviour Modelling for Web Traffic  non-linear interdependency between QoE and QoS  timely behavior  Reputation Management  Work plan

14 14 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Interdependency between QoE and QoS  Comparing iLBC and G.711 voice codecs  Similar results for both codecs regarding packet loss  IQX (exponential interdepency) cannot be rejected iLBCG.711

15 15 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Impact of Autocorrelated Delays  For different correlation factors, still exponential relationship valid  Clear impact of correlation, i.e. timely dependencies, on QoE

16 16 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Combining Active and Passive Measurements Viewing Time V Web Page WWW Session InterSessionTime I Inline Object GetReq. TCP 1 TCP 2 TCP 3 TCP 4 GetReq. Inline Object Inline Object GetReq.Inline Object Inline Object GetReq. Inline Object Main Object GetReq. Web Page Number X of Web Pages GetReq. Volume R of GetRequest Volume M of Main Object Volume O of Inline Object Number N of Inline Objects N User will abort if QoE is too bad or enjoy browsing and prolongs sessions for good QoE Content and usage of web is changing download of documents: pdf, ppt, … video streams services like chat or RDP Web page may not only be provided by a single server, but from a CDN from different service providers (Akamai, ads server, …)

17 17 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Agenda  Impact of User Behavior  Example: rate control in UMTS  Active and passive measurements  QoE and User Behaviour Modelling for Web Traffic  non-linear interdependency between QoE and QoS  timely behavior  Reputation Management  Work plan

18 18 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Reputation concept  Reputation is a proven mechanism for reflecting aggregated level of trust to network services, users, shared resources (e.g. auctioning systems, P2P networks, distributed wireless networks such as MANET; eBay, eDonkey, SecMon)  Reputation management is a feedback decision process being in charge of examining the given reputation (e.g. QoE, service performance) and triggering/enforcing remedy procedures on the on-line or threshold basis  Key features of reputation  present and historical measurements are weighted and reflect an its evolution and dynamics  in distributed P2P environments reputation is shared among network nodes reinforcing decision process  based on historical measurements estimates future expectations

19 19 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Reputation application in QoEWeb  Reputation building  For a particular Web service/Web traffic a perceived level of user satisfaction ST is expressed by QoE metrics and quantified according to the created model of user behaviour  Own experience OE of reputation is fed by ST, applying historical data shaping with WMA function   For shared reputation V service reputation SR is created with respect to credibility of recommenders IR  Reputation usage in QoEWeb  Evaluation of QoE metrics dynamic with respect to a particular Web services (web surfing, high throughput data, live streaming, interactive real time communication, etc)  Detects deterioration of networks performance before the user perceived QoE goes down below a critical level

20 20 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Agenda  Impact of User Behavior  Example: rate control in UMTS  Active and passive measurements  QoE and User Behaviour Modelling for Web Traffic  non-linear interdependency between QoE and QoS  timely behavior  Reputation Management  Work plan

21 21 Tobias Hoßfeld hossfeld@informatik.uni-wuerzburg.de Work Plan


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