Transcript Main Title - University of California, Berkeley

Wireless Sensor Networks
as The Next Tier of the Internet
David E. Culler
[email protected]
Arch Rock Corp.
University of California, Berkeley
Sensors Expo
6-6-06
The Internet Today
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The Internet Tomorrow
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The Internet ~ The World
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Physical Information Streams
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010010001…
• Sensors are everywhere
– But the data is mostly dropped on the floor
• Physical => Digital => Information
• Each sensor becomes a network citizen
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Why are they so Important?
Save Resources
Improve Productivity
Enable New Knowledge
Increase
Comfort
Enhance Safety & Security
Preventing Failures
High-Confidence Transport
Improve Food & H20
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Protect Health
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The Next Tier of the Internet” ?
• More than protocols - IP/TCP/HTTP
• Open Building blocks for physical information
– platforms, systems, networks
• Open Process for Networking Excellence
– Reference implementations leading to standardized
protocols and interfaces
• Design philosophy
– Expect Change, Failure, Uncertainty, Unexpected
• Enable broad applications
– Web services
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Emergence of Open Platforms
Proprietary WSN nodes
Silicon
World
Wireless
Berkeley open
WSN “motes”
Processing
Storage
Sensors
Physical
World
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Emergence of Open Systems
Digital
World
Silicon
World
WSN mote platform
Wireless
Processing
Storage
Sensors
Physical
World
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Snapshot of an International Community
346,000+ downloads from
tinyos.net
-plus sourceforge,
crossbow, moteiv,
www.tinyos.or.kr, …
Open TinyOS Alliance
http://www.tinyos.net
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TinyOS 2.0
Wireless Embedded Systems
Over-the-air
Programming
Network
Protocols
Link
Radio
Serial
Applications and Services
Blocks,
Logs, Files
Flash
Scheduling,
Management
Streaming
drivers
MCU, Timers,
Bus,…
ADC,
Sensor I/F
WSN mote platform
Wireless
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Storage
Processing
Communication Centric
Resource-Constrained
Event-driven Execution
Sensors
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Wireless Embedded Networks
Over-the-air
Programming
Network
Protocols
Digital
World
Silicon
World
Link
Radio
Serial
Applications and Services
Blocks,
Logs, Files
Flash
Scheduling,
Management
Streaming
drivers
MCU, Timers,
Bus,…
ADC,
Sensor I/F
WSN mote platform
Wireless
Storage
Processing
Sensors
Physical
World
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Multi-Hop Mesh Routing
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0
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Applications => Network Characteristics
• Monitoring Spaces
–
–
–
–
Env. Monitoring, Conservation biology, ...
Precision agriculture,
built environment comfort & efficiency ...
alarms, security, surveillance, EPA, OSHA, treaty verification …
• Monitoring Things
–
–
–
–
condition-based maintenance
automated meter reading
disaster management
Civil infrastructure
• Interactions of Space and Things
– manufacturing, asset tracking, fleet & franchise
– context aware computing, non-verbal communication
– Assistance - home/elder care
• Action and control
– Optimizing processes
– Automation
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Embedded Networking Requirements
• Reliable Dissemination
• Data Collection and Aggregation
• Point-to-point Transfers
• Reliably over lossy links
• At low power
– Idle listening, management, monitoring
• Adapting to changing conditions
• Scalar and Bulk Versions
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Diversity of Networks
Applications and Services
Network
Blocks,
Logs, Files
Ember
ZNet
Zigbee
Wireless
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Flash
Storage
Scheduling,
Management
Streaming
drivers
MCU, Timers,
Bus,…
ADC,
Sensor I/F
WSN mote
platform
Processing
Sensors
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Canonical SensorNet Network
Architecture
Sensor Node
Patch
Network
Sensor Patch
Gateway
Transit Network
(IP or not)
Client Data Browsing
and Processing
Access point
- Base station
- Proxy
Intranet/Internet (IP)
Other information
sources
Data Service
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How will SensorNets and IP play together?
XML / RPC / REST / SOAP / OSGI
HTTP / FTP / SNMP
TCP / UDP
IP
Ethernet
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Sonet
802.11
802.15.4, CC, …
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Beware “IP hype”
• Pushing HTML over a wireless connection to a serial port
attached to a PC is NOT running IP on the sensorNet
• Nor is packet-scraping into XML-RPC
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1st Internet Principle: IP “hour glass”
Application
XML / RPC / REST / SOAP / OSGI
Session
HTTP / FTP / SNMP
Transport
Network routing
TCP / UDP
IP
Link
Physical
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Ethernet
Fiber
Sonet
10BT Coax Serial
802.11
…
DSS
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QPSK
2nd Internet Principle:
End-to-End Architecture
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Full IP stack throughout
XML / RPC / REST / SOAP / OSGI
HTTP / FTP / SNMP
TCP / UDP
IP
Ethernet
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Sonet
802.11
802.15.4, CC, …
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Sensor Net Challenges for traditional IP
• Large headers <> small packets
• Very different protocol assumptions
– Low-power
– Intermittent connectivity (mostly sleeping)
– Loss ≠> Congestion
• Very different traffic patterns
– Not universal point-to-point file transfer
– Aggregate collection, dissemination
• Naming
– The data is important, not the machine
• Mobility
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Enterprise-Scale Sensor Nets
Gateways
Internet
SensorNet Patch
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The Internet: End-to-End no more…
Network
Address
Translation
Firewall
Load
Leveler
Switch
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XML / RPC / REST / SOAP / OSGI
HTTP / FTP / SNMP
TCP / UDP
IP
Ethernet
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Sonet
802.11
Proxy / Gateway
Edge Network Approach
802.15.4, CC, …
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Hybrid approach
• Security
– No IP to the nodes, attacks have to get through the gateway
or be physically close
• Namespace management
– Name nodes, networks, services
– Hosts, URLs, …
• Mask intermittent connectivity
– Terminate IP on the powered side
– Loosely couple, energy aware protocols on the other
• Distillation proxies
– Small binary packets where constrained
– Expanded to full text, XML, HTML, web services
• Rich suite of networking techniques in the Patch
unimpeded by overall internet-scale process
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SensorNets need the Wisdom
of the “Internet Architecture”
• Design for change!
• Network protocols must work over a wide variety of links
– Links will evolve
• Network protocols must work for a variety of applications
– Applications will evolve
• Provide only simple primitives
– Don’t confuse the networking standard with a programming
methodology
• Don’t try to lock-in your advantage in the spec
• Open process
• Rough consensus AND running code
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Networking vs Distributed Applications
• IP, 802.15.4, Zigbee are still “plumbing”
• Enterprise information infrastructure
means Integration with Applications
– The data, how it is represented, what it
means
– The operations you can do on it
– How it is obtained from the physical world
– Actions based on it
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Database View of the World
• The World is a
Database
– SQL, ODBC/JDBC
– The good old days of
client-server
– Data warehouses and
distributed databases
– Network taken for
granted
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Web Services
• The ultimate interoperability
• unify within and between enterprises
– Service Oriented Architecture
– Widely adopted standards
•
•
•
•
Backed by OASIS and W3C
Open-source reference implementations, e.g., Apache
SOAP + WSDL (+ UDDI)
Or XML-RPC over HTTP (REST)
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Web Service*
Platform and implementation independent
software component that can be
• Described using a service description
language
• Published to a registry of services
• Discovered through a standard mechanism
• Invoked through a declared API
– Usually over a network
• Composed with other services
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* Building Web Services with Java, Graham33et al, SAMS 2002
Service Oriented Architecture
Service
Registry
Service
Description
find
Service
Requestor
publish
bind
Service
Provider
• Service Description => interface & implementation
– Operations supported, input/output objects
– Bindings to network and data encoding schemes
– Network address where service can be invoked
• Enough that client can generate code to access the service well
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Embedded Application Tier
• Embedded applications built on a
rich set of node services.
–
–
–
–
Timing, sensor streams, storage
Local processing
Reliable, low-power communication
Platform independent + extensions
client
tier1
server
tier2
tier3
Networking Protocols
Common Link Abstraction
TinyOS Runtime Services
physical info net
Management
Embedded Application
SensorNet
GW/Proxy
tier4
“mote”
Sensors
Physical World
Hardware Abstraction Layer
MCU
Radio
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WSNs and Web Services
• Decorate external interface points
client
tier1
– Attributes (shared data)
– RPCs (control points)
– Events (signals)
server
tier2
temp
Networking Protocols
Common Link Abstraction
TinyOS Runtime Services
Management
@attribute
alarm @event
@rpc
test
Embedded Application
tier3
SensorNet
GW/Proxy
physical info net
tier4
SensorNet
mote
sensor
Hardware Abstraction Layer
MCU
Radio
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WSNs and Web Services
• Auto-generate Web Services
client
tier1
– Service description
– Service implementation
server
tier2
tier3
Networking Protocols
physical info net
Management
Embedded Application
SensorNet
GW/Proxy
tier4
SensorNet
mote
Embedded Web Service
Common Link Abstraction
TinyOS Runtime Services
sensor
Hardware Abstraction Layer
MCU
Radio
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WSNs and Web Services
• Auto-generate Web Services
client
tier1
– Service description
– Service implementation
server
tier2
tier3
SensorNet
GW/Proxy
physical info net
tier4
SensorNet
mote
Embedded Web Service
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sensor
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A new WSN world
client
tier1
AquaLogic
server
tier2
Perl
tier3
SensorNet
GW/Proxy
Python
tier4
NetWeaver
physical
info net
Embedded
Services
SensorNet
mote
C#
sensor
Excel
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Sensor Web Services
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Pick your favorite client
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Real World Webs
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Take-aways
• WSN building blocks are here
• Enterprise Integration IS the key to the WSN
future
– Enterprises large, small, distributed, indoor, outdoor,
residential, industrial, …
• Integrate the applications, not just the network
– Independent of the transport, platform,.. (plumbing)
• Web Services provide the framework
– But the underlying infrastructure must be Rock Solid
and extensible
– The “plumbing” has to really really work
• Reliability, power, management, adaptation, life-cycle, …
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Arch Rock
• Connecting the physical world to the
information enterprise
Client
tier1
• Solid Foundation
J2EE
SOAP
– High-quality, Cross-Platform embedded
application infrastructure
tier2
• Standard-based
internet
– OS, Networking, Services
• Novel information in familiar forms
– Auto-generated from embedded
application
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SensorNet
GW/Proxy
tier3
– Reliable, efficient, extensible
– IP-accessible web services
Enterprise
Server
physical info net
tier4
sensor
Physical World
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SensorNet
mote
Uniting long-lost relatives
Home
Automation
Building
Automation
PC
Workstation
Minicomputer
Dedicated Controllers
VME
Mainframe
General Purpose Computing
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Instrumentation Computers
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