Brad Karp,



Wireless sensor networks promise great societal benefit, but they also
pose significant technical challenges, arising from their
resource-constrained hardware and their expected large scale of
deployment. In this talk, I will describe designs for two scalable
communication primitives for wireless sensor networks: any-to-any
routing and distributed storage. Any-to-any routing allows any node in
a network to reach any other by forwarding through a series of
intermediate nodes. I will present Greedy Perimeter Stateless Routing
(GPSR), a geographic routing protocol, which makes forwarding
decisions using the *locations* of network nodes. GPSR consumes far
less storage per node and network bandwidth—both in short supply on
memory- and bandwidth-poor sensor platforms—than do previous
approaches to routing. I will also relate our experience deploying
GPSR on indoor sensor mote testbeds; experience with the vagaries of
real radio propagation gave rise to significant improvements to GPSR,
ultimately leading to a version of GPSR that routes provably correctly
on any connected network graph, wireless or wired.

Building upon GPSR, I will then briefly describe the Geographic Hash Table (GHT), which stores sensed events by name within a sensor network, and allows users to query for sensed events by name. GHT aggregates events with the same name at the same *location* in the network; by doing so, it spends less energy on network communication than previously proposed approaches, including Directed Diffusion and
TAG. GHT also locally replicates stored data to ensure robust persistence under random node failures.

I will conclude by briefly summarizing my other ongoing research projects, including Autograph, a system for automated, accurate Internet worm signature generation; and Open DHT, a publicly
accessible DHT infrastructure service that eases development of distributed Internet applications.


Brad Karp earned a B.S. at Yale University, an S.M. at Harvard University, and a Ph.D. at Harvard University, all in Computer Science. In his dissertation, he developed geographic algorithms for building robust, scalable routing systems for wireless sensor networks, and other large-scale wireless networks with dynamic topologies.

He was a staff scientist at ICIR, the ICSI Center for Internet Research (previously named ACIRI) at Berkeley between the fall of 2000
and fall of 2002. He joined Intel Research as a Staff Researcher and Carnegie Mellon’s Computer Science Department as an Adjunct Assistant
Professor in September 2002. In October 2005, he will take up a post as a Senior Lecturer at University College London’s Computer Science

Brad’s research interests lie at the intersection of networked systems, their algorithms, and their architectures. His work spans routing and storage for sensor networks; Internet worm quarantine; distributed application architecture for the Internet; and Internet congestion control.


Date: 2005-Jul-11     Time: 17:00:00     Room: 336

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