I am a Ph.D candidate in the Computer Science Department at Carnegie Mellon University. I am co-advised by
Professor David Andersen and
Professor Hui Zhang.
Research Projects
My interests span topics in networked computer systems and Internet architecture. In particular, I am motivated by discovering solutions that are practical, deployable, and flexible.
Simple Wide-Area Multi-Path (SWAMP)
We are exploring routing architectures to improve Internet availability using multiple concurrent interdomain end-to-end paths. Our first design focuses on a simple, effective, and
economically-friendly architecture to promote real-world deployment. We find that providing path choice at both a multi-homed source
and destination can provide nearly as many AS disjoint paths as a policy-free source routing mechanism could. Please see our
technical report for measurement details and analysis. Based on this result, SWAMP can provide end-hosts with several disjoint paths in an architecture conducive for deployment. More details on SWAMP to come.
Collaborators: David Andersen, Hui Zhang
Incast: TCP Throughput Collapse in Cluster-based Storage Systems
In TCP-based high-bandwidth, low-latency storage area networks where one client synchronously requests data striped across many servers, TCP throughput has been observed to be one or two orders of magnitude less than the client's link bandwidth. This throughput collapse poses a problem for storage servers running on commodity hardware (Ethernet/IP), especially considering the
recent push for a 100GigE Ethernet standard for high-performance networked computing. We have successfully reproduced the Incast phenomenon in simulation and real-world deployments and are currently investigating solutions to remedy this collapse.
Collaborators: Elie Krevat,
Amar Phanishayee,
David Andersen,
Greg Ganger,
Garth Gibson,
Srini Seshan.
FAWN: Fast Array of Wimpy Nodes
In today's typical system architectures, high-speed,
power-hungry multi-core processors are separated from persistent storage
devices via a hierarchy of fast, volatile memory. However, for
workloads which do not benefit from locality of reference, such as
query-driven workloads (e.g. DNS), the benefit of a high-speed processor
is wasted. This increasing CPU-memory-disk gap actually creates an
exciting opportunity, which is fueled by three
observations:
1) The throughput and seek times of modern magnetic disks have not kept
pace with the increase in CPU speeds.
2) Power consumption increases super-linearly with speeds.
3) Flash memory is now cheaper per gigabyte than magnetic disk for 4GB
or less.
By placing cheap, flash storage next to small energy efficient
processors, we restore the balance between processing power and data
storage capabilities to obtain a scalable, energy-efficient, and
effective server architecture for an important class of query-driven and
scan intensive workloads.
Collaborators:
Jason Franklin,
Amar Phanishayee,
David
Andersen Publications
-
Measurement and Analysis of TCP Throughput Collapse in Cluster-Based Storage Systems.
Amar Phanishayee, Elie Krevat, Vijay Vasudevan, David Andersen, Gregory Ganger, Garth Gibson, Srinivasan Seshan.
To appear in Proceedings of File and Storage Technologies (FAST). February 2008.
-
On Application-level Approaches to Avoiding TCP Throughput Collapse in Cluster-Based Storage Systems. [pdf]
Elie Krevat, Vijay Vasudevan, Amar Phanishayee, David Andersen, Gregory Ganger, Garth Gibson, Srinivasan Seshan.
In Proceedings of Petascale Data Storage Workshop, Supercomputing. November 2007.
Technical Reports
-
Understanding the AS-level Path Disjointness Provided by Multi-Homing. [pdf]
Vijay Vasudevan, David G. Andersen, Hui Zhang
CMU Tech Report: CMU-CS-07-141
Presentations
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"AS-Level Path Disjointness", Networking Seminar
-
"The Incast Phenomenon", Networking Seminar
Past Projects
As an undergraduate at Berkeley, I worked on two projects in
Ken Goldberg's
Berkeley Automation Lab. Specifically, I was the network engineer on the
Ballet Mori project and also worked on physical deformation simulations for
needle surgery planning.
I also worked on DDoS prevention in next generation Internet architectures and implemented ConeNAT functionality within the
OCALA framework.
Friends
CMU
David Brumley
Jason Ganetsky
Swapnil Patil
Amar Phanishayee
Kanat Tangwongsan
Dan Wendlandt
Elsewhere
Beverly Wang
Kevin Lin
Chris Crutchfield
Robert D. Gregg