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Licentiate Seminar: On Measurement and Analysis of Internet Backbone Traffic. Wolfgang John Department of Computer Science and Engineering Chalmers University of Technology G öteborg, Sweden. Why measure Internet traffic? (1). The Internet is changing in size. Internet, 1983. Internet, 2005.
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Licentiate Seminar:On Measurement and Analysis of Internet Backbone Traffic Wolfgang John Department of Computer Science and EngineeringChalmers University of TechnologyGöteborg, Sweden
Why measure Internet traffic? (1) The Internet is changing in size Internet, 1983 Internet, 2005 ARPANET, 1969
Why measure Internet traffic? (2) The Internet is changing in application
Why measure Internet traffic? (3) • The Internet • is constantly developing • is used differently in different locations • is heterogeneous The Internet is not understood in its entirety! INTERconnected NETworks NET INTER
Why measure Internet traffic? (4) • Operational purpose • Troubleshooting, provisioning, planning …. • Scientific purpose • Protocols, infrastructure and services • Performance properties • Internet simulation models • Security measures
Thesis Objectives • Guidelines for Internet measurement • Current traffic characteristics • Traffic decomposition • Inconsistent behavior
Outline • Measurement approaches • Internet measurement challenges • The MonNet project • Scientific contribution • Results • Four studies included • Conclusions Measurement Analysis
Measurement approaches Network traffic measurement Passive Active Software Hardware Online Offline Packets Flows Statistical summaries Complete Headers Different protocol levels Transport layer
Internet measurement challenges (1) • Legal considerations • Ethical and moral considerations • Operational considerations • Technical considerations
Measurement challenges (3) Technical considerations • Data amount • Exhausting I/O and storage access speeds • Data reduction techniques • Filtering, sampling, packet truncation • Timing • Clock synchronization
The MonNet Project (1) Technical Solution Processing Platform and Storage Measurement Node 1 splitter 10 Gbps Göteborg Borås 10 Gbps Measurement Node 2
The MonNet Project (2) Measurement location • April 2006 148 traces (20 minutes) 11 billion packets, 7.6 TB of data • Sept. – Nov. 2006 554 traces (10 minutes) 28 billion packets, 19.5 TB of data Internet Stockholm Student-Net Borås Regional ISPs Göteborg Göteborgs Univ. Chalmers Univ. Other smaller Univ. and Institutes
Level of complexity Scientific Contribution Packet level Flow level Traffic classes Traffic characterization Study III Study II Study I Study IV Quantification of inconsistent behavior Upcoming
Study I: Packet Level Analysis • Updated packet-level characteristics of Internet traffic • Inconsistencies in headers will appear • Network attacks and malicious traffic • Active OS fingerprinting • Buggy applications or protocol stacks
Study II: Flow level analysis • High level analysis does not necessarily show differences → detailed analysis does! • 2 main reasons for directional differences: • Malicious traffic • the Internet is “unfriendly” • P2P • Göteborg is a P2P source • P2P is changing traffic characteristicse.g. packet sizes, TCP termination, TCP option usage
Study III: Classification Method (1) • Classification of flow traffic without payload • Heuristics to identify nature of endpoints • Rules based on connection patterns and port numbers • 5 rules for P2P traffic • 10 rules to classify other types of traffic • remove ‘false positives’ from P2P
# connections in 106 Amount of data in TB Study III: Classification Method (2) Comparison of classification methods for P2P traffic
Study III: Classification Method (3) • Previous classification methods on packet header traces don’t work well on backbone data • Proposal of refined and updated heuristics • Simple and fast method to decompose traffic • No payload required • Effectively used even on short traces (10 min) • 0.2% of the data left unclassified
Study IV: Classification Results (1) Tuesday, 18.04.2006
Study IV: Classification Results (2) Application breakdown April till Nov. 2006
Study IV: Classification Results (3) Connection establishment for traffic classes
Study IV: Classification Results (4) • Behavior of P2P traffic • Unsuccessful TCP connection attempts increasing • Serving peers terminate with FIN and RSTDecreased from 20% to 8% • UDP overlay traffic doubled • TCP options deployment differs • P2P behaves as expected • Web traffic shows artifacts of client-server pattere.g. popular web-servers neglecting SACK option
Summary • Guidelines for Internet measurement • Experiences of the MonNet project • Current traffic characteristics • Packet and flow level • Traffic decomposition • Traffic classification method • Inconsistent behavior • Packet header anomalies • Malicious traffic flows
General remarks • Internet today is essential, but still not understood entirely • Large-scale traffic measurements uncommon • A lot of analysis is done on outdated datasets • Each study generated as much questions as answers • Reconsider measurement process (duration, payload…) • A lot of open questions … …get more answers in two years…