Network Embedded Systems Technology
Winter 2003 Retreat
January 15-17, 2003
As we approach the middle of the NEST project, we want to utilize this retreat to examine the project in light of the changes around it. Due in substantial part to our efforts, there are now hundreds of groups investigating the sensor network space - at least a hundred using our platform - numerous start up and significant interest from established corporations.
The TinyOS of Tomorrow [pdf] - Phil Levis
Point, Counterpoint: nesC [pdf] - Phil Levis
The nesC Language: A Holistic Approach to Networked Embedded Systems
- [pdf] - David Gay, Phil Levis, Robert von Behren, Matt Welsh, Eric Brewer and David Culler
We present nesC, a programming language for
networked embedded systems, such as sensor network “motes,” which represent a
new design space for application developers. Sensor networks consist of
(potentially) thousands of tiny, low-power “motes,” each of which execute
concurrent, reactive programs that must operate with severe memory and power
constraints. nesC’s contribution is to support the special needs of this
domain by exposing a programming model that incorporates event-driven
execution, a flexible concurrency model, and component-oriented application
design. Restrictions on the programming model allow the nesC compiler to
perform whole-program analyses, including data-race detection (which improves
reliability) and aggressive function inlining (which reduces resource
consumption). nesC has been used to implement TinyOS, a small operating
system for sensor networks, as well as several significant sensor
applications. nesC and TinyOS have been adopted by a large number of sensor
network research groups, and our experience and evaluation of the language
shows that it is effective at supporting the complex, concurrent programming
style demanded by this new class of deeply networked systems.
DOT3 radio stack [pdf] - Jaein Jeong, Sukun Kim
Our network stack is implemented on a new
platform of wireles sensor DOT3 which has better coverage and reliability
than the current generation of wireless sensor, MICA. In outdoor tests, the
packet receiving rate was close to 100% within 800ft and was reasonably good
up to 1100 ft. This was made possible by using an error correction code and
a reliable transport layer. Our implementation also allows us to choose a
frequency among multiple channels. Using multiple frequency as well as
reliable transport layer we could achieve high packet receiving rate by
paying additional retransmission time when collision was increased with more
number of sensor nodes. Being written in nesC programming language, our
network stack is compatible with the latest generation of TinyOS code.
Wireless Sensor Networks for Habitat Monitoring [pdf]
- Alan Mainwaring, Joseph Polastre, Robert Szewczyk, David Culler and
John Anderson
We provide an in-depth study of applying wireless sensor
networks to real-world habitat monitoring. A set of system
design requirements are developed that cover the hardware
design of the nodes, the design of the sensor network, and
the capabilities for remote data access and management. A
system architecture is proposed to address these requirements
for habitat monitoring in general, and an instance of
the architecture for monitoring seabird nesting environment
and behavior is presented. The currently deployed network
consists of 32 nodes on a small island o the coast of Maine
streaming useful live data onto the web. The applicationdriven
design exercise serves to identify important areas of
further work in data sampling, communications, network retasking,
and health monitoring.
Maté: A Tiny Virtual Machine for Sensor Networks [pdf]
- Phil Levis and David Culler
Composed of tens of thousands of tiny devices
with very limited resources ("motes"), sensor networks are subject
to novel systems problems and constraints. The large number of motes in a
sensor network means that there will often be some failing nodes; networks
must be easy to repopulate. Often there is no feasible method to recharge
motes, so energy is a precious resource. Once deployed, a network must be
reprogrammable although physically unreachable, and this reprogramming can be
a signicant energy cost. We present Maté, a tiny communication-centric
virtual machine designed for sensor networks. Maté's high-level interface
allows complex programs to be very short (under 100 bytes), reducing the
energy cost of transmitting new programs. Code is broken up into small
capsules of 24 instructions, which can self-replicate through the network.
Packet sending and reception capsules enable the deployment of ad-hoc routing
and data aggregation algorithms. Maté's concise, high-level program
representation simplifies programming and allows large networks to be
frequently reprogrammed in an energy-effcient manner; in addition, its safe
execution environment suggests a use of virtual machines to provide the
user/kernel boundary on motes that have no hardware protection mechanisms.
Secure Routing in Wireless Sensor Networks: Attacks and Countermeasures
[pdf] - Chris Karlof and David
Wagner
We consider routing security in wireless
sensor networks. Many sensor network routing protocols have been proposed,
but none of them have been designed with security as a goal. We propose
security goals for routing in sensor networks, show how attacks against
ad-hoc and peer-to-peer networks can be adapted into powerful attacks
against sensor networks, introduce two classes of novel attacks against
sensor networks — sinkholes and HELLO floods, and analyze the security of
all the major sensor network routing protocols. We describe crippling
attacks against all of them and suggest countermeasures and design
considerations. This is the first such analysis of secure routing in sensor
networks.