1. Overcoming the Internet Impasse through Virtualization Presented by: Aaron Ballew Sagar Vemuri Larry Peterson, Scott Shenker, Jonathan Turner

2. Motivation Impasse in the current Internet There is interest in studying new architectures New architectures cannot be evaluated Even if they could, cannot be deployed

3. The Idea of Architecture Gives system parameters Fewer variables to deal with Can be violated if it benefits you Promotes interoperability Does not mandate it No need to recreate everything from the bottom up for every new idea

4. Our Argument Live experimentation with new architectures is problematic Traditional testbeds have severe limitations Ability to evaluate and deploy new architectures is quite limited. Call to return to the roots of roots of applied architectural research instead of being satisfied with paper designs We will provide you the means to test your new architecture

5. Difficulties in adopting a new architecture Requires changes in routers and host software Requires ISPs to jointly agree to support the architecture Ad hoc work-arounds serve a valuable short-term purpose without offering long-term flexibility Live experimentation is problematic

6. Overcoming the Impasse Ability to easily experiment with new architecture on live traffic Availability of deployment path for architectural ideas to be put into practice Address a broad range of problems rather than focussing on a single narrow problem.

7. Means of testing new architectures Simulation / Emulation Physical Testbeds Production-oriented Research-oriented Overlays

8. Simulation Only as good as the model

9. Physical Testbeds Leased lines connecting a limited set of locations Utilize dedicated transmission links Small geographic extent Expensive to operate at a very large scale Expensive and time consuming to create for each experiment

10. Production Testbeds Support real traffic from real users Provide valuable information about the operational behavior of an architecture Users have no choice on participation Extremely conservative in their experimentation

11. Research Testbeds Driven by synthetically generated traffic and/or a small collection of users Do not carry traffic from a wide variety of real users Results much less indicative due to lack of real operational viability

12. Overlays Not limited geographically Users can access from anywhere Usage can be voluntary Users can decide whether or not to participate in an overlay No significant expenditure

13. Overlays … 2 Underutilized tool due to high barrier to entry Largely seen as a way of deploying narrow fixes to specific problems Little thought devoted to deal with the big picture Architecturally tame Most assume IP as the architecture inside the overlay itself Need a philosophical change rather than a technical change in how they are used

14. Virtual Testbed Proposed to overcome the problems of Testbeds and Overlays Support multiple simultaneous architectures Reduce the barrier to entry for new architectural ideas Provides a clean path for radical new architectures to be globally deployed

15. Virtual Testbed … 2 Two basic components Overlay substrate A set of dedicated but multiplexed overlay nodes Allows multiple experiments to be run simultaneously Proxy mechanism Allows any host to opt-in to a particular experiment Treats a nearby overlay node as the host ’ s first hop router

16. The Substrate Could use the existing PlanetLab ’ s infrastructure Consists of a set of virtual routers connected into whatever topology the experimenter selects Runs whatever the experimenter designs Does not have to be IP!

17. Opting In Can take advantage of existing DNS system, to direct users into or not into the VT. The VT is then free to do whatever it wants with the packets, using whatever IP or non-IP protocols are appropriate to service the packet, and tunneling over protocols it hopes to replace

18. Considerations Security By using non-IP inside the VT, perhaps interfere with IP-based security Interesting problem, and worth looking at. Enjoy yourself. QoS Nothing is perfect. Intra-VT QoS is still present. The underlying variations can be treated as Noise. No reason to abandon the study of noisy signals. QoS may not be pertinent to a particular experiment anyway.

19. Deployment Leverage the strength of overlays Can occur independently without any coordination between various deployments No mandate for a particular architecture. Market forces will address, just as it does today.

20. Purists Believe that IP is the single universal protocol Overlays are necessary evils that are reluctantly tolerated Virtualization is only a means by which new architectures are installed, not a fundamental aspect of the architecture itself Aim for flexibility of an architecture giving importance to long term goals

21. Pluralists View IP as only one of the several different components of the Internet Overlays are just one more way to deliver services to the users Architecture evolves dynamically and is the union of existing overlays and protocols More emphasis of short-term improvements

22. Virtualization Virtual Testbed uses virtualization in two crucial ways Used in a typical overlay sense The client proxy plus the virtual links allow the overlay to be qualitatively equivalent to a native network Multiplexing allows many virtual testbeds to operate simultaneously Greatly reduces the barrier-to-entry

23. Virtualization Virtualization Techniques are not tied to the architecture being tested. If architectural changes are rare Virtualization is only a means to accomplish the architectural shifts If Internet is in a constant change of flux Virtualization plays the central role

24. To Reiterate We recognize the interest and value in architectural research We want researchers to have a place to work and test their ideas We are not interested in mandating a particular solution to anyone

25. Thank You Questions?