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Overcoming the Internet Impasse through Virtualization
Presented by:Aaron BallewSagar Vemuri
Larry Peterson, Scott Shenker, Jonathan Turner
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
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
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
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
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.
Means of testing new architectures
Simulation / Emulation Physical Testbeds
Production-oriented Research-oriented
Overlays
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
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
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
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
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
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
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
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!
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
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.
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.
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
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
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
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
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