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Peer to Peer Overlay Network for Sensor net
Eng. Husam Alzaq Computer Engineering Department
Islamic University of [email protected]
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
AgendaConclusionDesign & EvaluationBackgroundIntroduction
Introduction Background on
Wireless Sensor Network Peer to Peer Systems
Concept Implementation Results Conclusion
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
What are Wireless Sensor Nodes?ConclusionDesign & EvaluationBackgroundIntroduction
They are small electronic components capable of sensing many types of information from the environment.
They are equipped with a certain amount of computational power, communication, storage and often actuation resources.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
What is WSN?ConclusionDesign & EvaluationBackgroundIntroduction
It is a network that has multiple nodes connected to each other wirelessly
Sensor Network is distributed and is not structured.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Constraints/ChallangesConclusionDesign & EvaluationBackgroundIntroduction
Hardware Power Consumption
Software Issues to be addresses:
Lifetime maximization Robustness and fault tolerance Self-configuration
Algorithms Design of energy-aware algorithms
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
MotivationConclusionDesign & EvaluationBackgroundIntroduction
Motivation Home/Office Observing
–How can a user connect to Wireless Sensor Network over Internet?
–How can a user retrieve the sensor data?
What is the temperature
at lab146??
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
MotivationConclusionDesign & EvaluationBackgroundIntroduction
Solution Peer to Peer Systems provide an
overlay network that is able to connect a user to a Wireless Sensor Network.
Declarative Query would serve as a way to express user’s requests.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
A Middleware for Sensor NetworksConclusionDesign & EvaluationBackgroundIntroduction
A middleware for sensor networks supports the development, maintenance, deployment, and execution of sensing-based applications.
Building a Peer to Peer application on existing WSN is important. The complexity of accessing different sensor
nodes must be hidden. Many services can be offered.
– Discovering Sensor gateway– Obtaining sensor data
Distributed Wireless Sensor Networks (WSNs) can be observed.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Peer to Peer SystemsConclusionDesign & EvaluationBackgroundIntroduction
A Peer to Peer system is defined as a class of systems and applications that employs distributed resources to perform a critical function in a decentralized manner.
The resources encompass computing power, data, network bandwidth ...etc.
The critical function can be distributed computing, data/content sharing, communication and collaboration, or platform services.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Peer to Peer CharacteristicsConclusionDesign & EvaluationBackgroundIntroduction
Symmetry Decentralization Scalability Fault tolerant Self-Organization Resources Sharing Fast Resource Location to determine where to find the
resource
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Peer to Peer ClassificationConclusionDesign & EvaluationBackgroundIntroduction
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Peer to Peer ClassificationConclusionDesign & EvaluationBackgroundIntroduction
Un stru ctu re d Pe e r to Pe e rStructure d Pe e r to
Pe e r
Hyb rid Pu re (fu llyde ce ntralize d)
Su p e r-p e e rmo d e l
Distribute d Ha shTa ble (DHT)-Ba se d
1 . C en tra l pee r isnecessa ry top rov ide these rv ice .2 . C en tra l pee r isused to indexpee rs in fo rma tion .Examp le :Napste r
1 . A ll pa rtic ipan tsa re equa l.2 . Any pee r can beremoved withou tloss o f functiona lity3 . No cen tra l pee r.Examp le : F reene t
1 . T wo d iffe ren tpee rs.2 . Any pee r can beremoved withou tloss o f functiona lity3 . D ynamic cen tra lpee r.Examp le :Jx ta ,Kaz aa
1 . Sea rch ing ise ffective .2 . Manag ingnodes a reexpensive .3 . C onnections inthe ove r lay a re“fixed ” Examp les:C ho rd , C AN
P eer
P eer
le af no d e
S u p e r -n o d e
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Why Jxta?ConclusionDesign & EvaluationBackgroundIntroduction
Jxta is a generic overlay network system. It consists of a set of protocols that are language,
platform and network independent. Java based and C implementation
It connects devices on the network ranging from embedded system and cellular phones to PCs and servers.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Application OverviewConclusionDesign & EvaluationBackgroundIntroduction
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
RequirementsConclusionDesign & EvaluationBackgroundIntroduction
Application Requirements Detect sensor gateways. Express user‘s requests in a SQL
language. Filter sensor data according to user
request.
Technical Requirements. Scalability. Interoperability.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Conceptual Design - ArchitectureConclusionDesign & EvaluationBackgroundIntroduction
Jxta Layer Governs the connection between a gateway and user
agents, and the overlay network. Ensures the interoperability between a gateway and
user agents.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Conceptual Design - ArchitectureConclusionDesign & EvaluationBackgroundIntroduction
Sensor Gateway Layers Sensor Network Interface Layer.
– Extracts data from a sensor UDP packet and hands it to the Sensor Application layer.
Sensor Application Layer. – Manages all interactions between users and sensor nodes
such as filtering data.
User Agents Layers User Interface Layer. WSN Application Layer.
– Handles all user queries.– Handles all messages.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Conceptual DesignConclusionDesign & EvaluationBackgroundIntroduction
Block Diagram
User Agent Sensor Gateway
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Publishing & Discovery ProcessConclusionDesign & EvaluationBackgroundIntroduction
1. Sensor Gateway publishes Advertisements on sensor nodes.
2. Jxta Overlay Network indexes these advertisements.3. User Agent searches for advertisements.
Each advertisement includes Set of properties that describe the sensor gateway
– Name– Location– Description
Set of attributes that are provided by each sensor node. – types of data that the specified sensor can measure i.e.
temperature, light ... etc. and their units.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Message HandlerConclusionDesign & EvaluationBackgroundIntroduction
A gateway and a user agents exchange a Jxta XML messages over a Jxta pipe.
Messages are used to Create a new filter Remove a filter Send the filter results
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Distributed Query ProcessConclusionDesign & EvaluationBackgroundIntroduction
Requests are expressed in a SQL-like query language to retrieve sensor data.
User query consists of SELECT clause: specifies attributes, in which user is
interested in. FROM clause: specifies the name of the sensor
gateway. WHERE clause: filters sensor records by a predicate. DURATION clause: is the period of time, which
specifies how long the query should be run before terminated and removed from the filter list.
(Select * From lab146.ibr.cs.tu-bs.de where Temperature < 20 duration = 600)
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Distributed Query ProcessConclusionDesign & EvaluationBackgroundIntroduction
Query is distributively processed as follows:
1. The gateway name is extracted from the user query (specified in FROM) in order to establish a connection with the gateway.
2. The WHERE clause is encapsulated in a Query XML-based message.
3. The Query message is sent out to the gateway.
4. After that, the received results are displayed according to SELECT clause.
5. Query is terminated either by user or by gateway.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Filter ProcessConclusionDesign & EvaluationBackgroundIntroduction
Filter process is a way to suppress sensor tuples from randomly propagation and hand them in graceful manner to all interested users
Sensor tuples are a discrete raw of data generated at discrete time not stored in a data warehouse.
Filter is created by a user query. Filter is activated for each received tuples. Filter is only deleted in two cases
by user -> explicitly or implicitly time is up
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Filter ProcessConclusionDesign & EvaluationBackgroundIntroduction
Filter mechanism is based on attributes, which are described by key-value-operator. Key indicates the semantics of the attribute Operator describes how attributes will match when two
attributes are compared (<, >, =, ... etc.). . Typical attributes values
– Sensor reading includes, temperature, voltage, light ....etc.– Meta-data encompasses general information about a
sensor node e.g. sensor ID. – Internal state is any information that is not related to
sensor reading, such as timestamps.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
ImplementationConclusionDesign & EvaluationBackgroundIntroduction
A Sensor Gateway implements the basic functionality of the sensor agent.
The implementation is based on Jxta-C (version 2.5).
A User Agent prototype implements a user interface for JMSN, which is able to • discover advertisements• access any available sensor
network.
The implementation is based on Jxta J2SE platform.
A prototype for a sensor application over a Peer to Peer System is named as Jxta Middleware for Sensor Network (JMSN). It consists of:
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
User Agent, GUIConclusionDesign & EvaluationBackgroundIntroduction
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
EvaluationConclusionDesign & EvaluationBackgroundIntroduction
Test-bed Equipments Tests ware performed at the Workstation pool of IBR,
where twelve machines of identical hardware are used. They are equipped with
– Intel Pentium(r) D CPU 3.2GHz
– 2.00 GB of RAM
– Fast Ethernet card. Half of them run Windows XP and the other run Debian
GNU/Linux distribution.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Evaluation - Memory PerformanceConclusionDesign & EvaluationBackgroundIntroduction
This memory footprint is mainly due to the Apache Runtime (APR), which is embedded in the Jxta-C implementation.
It is observed that 8 threads are created (using DDD - Data Display Debugger)
Summary of memory consumption tests.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Evaluation – Filter OverheadConclusionDesign & EvaluationBackgroundIntroduction
Constant message size Time is linear in n with a slope of
210.4 ms/filter operation. The overhead of each filter
process includes the time to process the filter searching for user
PipeAdvertisement establishing a connection sending the message.
– TCP transport is using blocking I/O.
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0
500
1000
1500
2000
2500
0 2 4 6 8 10 12
Number of Filters
Ave
rage
Tim
e ( m
s )
Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
ConclusionConclusionDesign & EvaluationBackgroundIntroduction
Peer to Peer Systems provide a decentralized approach that does not require any costly infrastructure.
Jxta was selected among other systems since it is a generic overlay network that connects devices on the network.
The design of “Peer to Peer overlay network for sensornets” combines a peer service discovery with a distributed query processing.
JMSN design doesn‘t come without cost. Results showed that the current implementation of Jxta-C consumes memory, which is not efficient for embedded system with limited memory.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
Future WorkConclusionDesign & EvaluationBackgroundIntroduction
It is essential to extend the current version of Jxta-C implementation to cope with the limited memory devices.
It is necessary to enhance the user agent with complex query searching by partial names and attributes such as Location.
Aggregate function such as Average, Max, Count ...etc.
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Peer to Peer Overlay Netzwerk für SensorennetzeHusam Alzaq
ConclusionDesign & EvaluationBackgroundIntroduction
الستماعكم :; شكرًَاThanks for your attention
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