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Monitoring Network Bias

Monitoring Network Bias. Gergely Biczo k , Whitney Young , and Aleksandar Kuzmanovic Northwestern Networks Group ( http://networks.cs.northwestern.edu ) Supported by NSF CAREER Award No. 0746360. Motivation. Other probes DNS hijacking of mistyped web addresses

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Monitoring Network Bias

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  1. Monitoring Network Bias Gergely Biczok, Whitney Young, and Aleksandar Kuzmanovic Northwestern Networks Group (http://networks.cs.northwestern.edu) Supported by NSF CAREER Award No. 0746360 Motivation Other probes • DNS hijacking of mistyped web addresses • Blocking HTTP download of *.torrent files • Can add newly discovered probes modularly • Net Neutrality • Openness vs. managing traffic • Debate in public, struggle in legislation, war in the Internet • ISPs are already installing middleboxes capable of degrading/changing/blocking popular applications We do not take sides… • …but want to facilitate network accountability System Design Goal • Develop an end-host based measurement system for detecting and exposing biased network behavior Methodology Main idea • Collect reported/possible types of discriminatory ISP practices/middleboxes • Reverse-engineer their operation to create probes that will likely trigger them (approximately emulate desired traffic pattern) • Detect and locate biased network elements Filtering • Port-based • Signature-based • Signature database compiled from open source tools, web search and packet traces • Flow-pattern-based • Spatial and temporal correlation of UDP and TCP flows specific to p2p applications Shaping • Extensive shaping reported for p2p and encrypted traffic • Compare HTTP/FTP data rates to SSL and BitTorrent (emulated) rates • Back-to-back minute-long experiments • Significant and consistent (across hosts from the same ISP) difference in data rates indicate the presence of shapers Locating middleboxes (filters and shapers) • Repeat the same measurements between the same end-host and multiple specifically selected PlanetLab nodes • Select servers that are “geographically” far away from each other minimizing the common segment of the paths • If same phenomena are observed, middlebox is in the shared path segments Central Server • Serves the main website • Selects multiple PL nodes for given end-host • Coordinates probing PL nodes • Handles incoming reports and generate feedback to users PlanetLab Node • If selected serves the Java applet to a Client • Sends and receives probes to/from a Client via applet • Sends a report to Central Server at the end of every measurement session Client • Runs an applet in a web browser • Sends and receives probes from multiple PL nodes • Sends reports to PL nodes • Displays results to the user in a browser Results and Future Work • Implementation is ongoing • Functions partly tested manually on small scale • Experienced BT shaping on well seeded torrents (D/U: 30 KBps/5 KBps) vs. HTTP download (200 KBps) at a given ISP • Signature-based filtering probes validated with open-source filtering software in a testbed • Large-scale live measurement in the near future • Upon collecting sufficient data we can draw a global map of biased network behavior

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