Network Operations and Internet Security Lab

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Anti-Censorship Tool Collage Featured in Slashdot

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Ph.D. student Sam Burnett developed Collage, a tool that relies on user-generated content sites like Flickr to help citizens in countries oppressed by censorship communicate more openly.  The basic idea is to hide censored content in seemingly innocuous photos that are hosted on user-generated content sites like Flickr.  Below is a conceptual diagram explaining how Collage works:


For more information about how Collage works, please see the full paper.  For more information, and to contribute to or download the code, please see the Collage project home page.

You can also read about Collage in various trade articles:



Colalge also appeared on Slashdot twice; Professor Feamster also recently blogged about Collage, here.

Last Updated on Thursday, 19 August 2010 05:45

Transit Portal Featured in Tech Review

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Ph.D. student Valas Valancius has been developing the Transit Portal, software that gives services hosted on cloud infrastructures like Amazon EC2 direct control over inbound and outbound traffic.  Different services may have different service requirements: some services may require connectivity that satisfies strict performance requirements (e.g., interactive services or gaming may require low latency or packet loss), while other services might wish to simply use the least expensive connectivity.  Unfortunately, today's cloud providers select the same routes for every service hosted on the cloud infrastructure (effectively doing "one size fits all" routing for all hosted services).

The Transit Portal allows each service hosted in a cloud to perform its own Internet routing.  For more information on Transit Portal, see the full paper, or check out the following articles:


Professor Nick Feamster also blogged about the Transit Portal here.  Lots of information about Transit Portal, including information about how to install a Transit Portal yourself, is available on the GENI project wiki for Transit Portal.


Last Updated on Thursday, 19 August 2010 06:06

Next-Generation Access Control at GENI Engineering Conference

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Hyojoon "Joon" Kim and Ankur Nayak presented a next-generation access control system called Resonance at the GENI Engineering Conference at Duke University in Durham, North Carolina.   The current Georgia Tech network access control framework is based on complicated network configuration settings, making it difficult for operators to debug the system, to make changes to it, and to implement complicated network policies.

Joon and Ankur have been developing a next-generation version of Georgia Tech's access control framework, based on OpenFlow.  The OpenFlow architecture decouples a network's control framework from individual network devices.  We are using this framework to allow operators to express more complex policies in a higher-level language.  The Resonance access control system is deployed on the Georgia Tech campus in research labs across three buildings.  We are in the process of evaluating this deployment for real users on the network.  A more widespread campus deployment is planned over the course of the coming year.

The video below shows the Resonance system in action.  You can also read a bit more about Resonance:

Last Updated on Tuesday, 20 April 2010 14:01

Network Neutrality Tool NANO at ACM SIGCOMM CoNext

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NANO ("Network Access Neutrality Observatory"), was presented at ACM SIGCOMM CoNext last Friday.

NANO detects whether a user's access ISP is discriminating against certain users, destinations or applications.  In contrast to existing tools, NANO relies primarily on data that is passively collected from user's machines.  To use NANO, simply download and install the NANO-Agent on your machine.  Currently, NANO-Agent runs only on Linux, but a Windows version will be coming shortly.

NANO is part of Google's Measurement Lab project.

For more information about NANO, please see the following:


Last Updated on Tuesday, 20 April 2010 14:10

OpenFlow Click Featured at Click Symposium

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Yogesh Mundada gave a talk at the Click Symposium in Belgium last week on his new OpenFlow Click Element, which he developed with Rob Sherwood at Deutche Telekom Labs.

The OpenFlow Click element is a module for the Click modular router that can be controlled via a standard OpenFlow controller.  The element essentially turns a Click router into a software switch with flow table entries.  One of the most powerful aspects of this paradigm is that it allows hybrid packet and flow processing, as part of a paradigm we call Flowlets.

More details about OpenFlow Click element are available here:

Last Updated on Thursday, 10 December 2009 08:35
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