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THE IRISH SOFTWARE ENGINEERING RESEARCH CENTRE1
WelcomeWeb services on embedded systems –A performance study
by Christin Groba and Siobhan Clarke
IEEE Workshop on the Web of Things, Mannheim, 29 March 2010
THE IRISH SOFTWARE ENGINEERING RESEARCH CENTRE
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Introduction
With the emergence of the Web of Things•
Communication via custom interfaces inflexible and impractical
•
Need for platform‐independent communication mechanism
Web services •
Support interoperability and seamless integration
•
Question remains whether feasible for embedded systems
Performance study•
Quantify the overhead of Web services
•
Provide empirical data as basis for decision on best technical solution
THE IRISH SOFTWARE ENGINEERING RESEARCH CENTRE
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Implementation•conventional•ksoap
library (61 kB)
•ws4d library (478 kB)
Metrics•disk space•message size•response time•energy consumption
Experimental setting
Client (Sun SPOT)
Service (Sun SPOT)
Request n readings
Return list of n readings
Conventional:value # timestamp # samplerid ; . . # . . # . . ;
Web service:<readings>
<reading><value> . . . </ value><timestamp> . . . </timestamp><samplerId> . . . </samplerId>
</reading><reading> . . . </reading>
</readings>
THE IRISH SOFTWARE ENGINEERING RESEARCH CENTRE
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Effect on message size
Overhead:
lower limit~5
Low‐power radio IEEE 802.15.4 •
120 byte for data
•
1 packet for conventional message•
7 packets for ksoap
message
•
10 packets for ws4d message
THE IRISH SOFTWARE ENGINEERING RESEARCH CENTRE
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Effect on response time and energy
Overhead:
lower limit~2.5
Overhead:
lower limit~3
Clie
nt si
de m
easu
rem
ents
THE IRISH SOFTWARE ENGINEERING RESEARCH CENTRE
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Effect on energy structure
Client-side
Service-side
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Summary
Web service overhead compared to conventional approach
•
At least 5 times larger messages
•
At least 2.5 times longer response time
•
At least 3 times higher energy consumption
Implication on wireless sensor networks
•
Overhead may outperform benefit of exchanging structured data with SOAP
•
Need for smaller messages to reduce response time and energy consumption
•
Need for smaller parsers to reduce memory footprint
THE IRISH SOFTWARE ENGINEERING RESEARCH CENTRE8
Thank you!
