Extending RTNS to Model Distributed Applications in MultiHop Topologies

1
Extending RTNS to Model Distributed Applications
in MultiHop Topologies
RETIS Lab
Real-Time Systems Laboratory
Research Area WSN
Mangesh Chitnis Paolo Pagano Giuseppe Lipari
2
Motivations

• To provide a full featured RTNS to simulate
• Network and Operating System aspects in
  wireless sensor networks.
• Rapid Application Prototyping and Validation
• Simulation of a WSN Application with RTNS.
• Deriving application relevant data (Result).
• Running the application on Hardware with OS
  Support.
• Validating the actual result with the simulated
  data.

3
Problems

• RTNS was developed for clustered network.
• In MultiHop Networks, the tool neglects the delay
  due to load in intermediate nodes.

Source
Gateway
Destination
RtSim
RtSim
RtSim
RtSim
RTR
RTR
RTR
Phy/Mac
Phy/Mac
Phy/Mac
Data
Wireless Medium
Routing
4
Main Idea

• The problem is due to the existing wireless model
  present in Ns-2.

• Node Entry
• Classifier
• Address
• Port
• RTModule
• Classifier.
• Routing Alg.
• Ns-2 Agents
• Ns-2 Applications

Node
RT App
RTAgent
RTR Agent
RTModule
Node Architecture in Ns-2
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Packet Flow
Source
Gateway
Destination
n0
n2
n1
?
RT App
RT App
Port Classifier
Port Classifier
RTAgent
Addr Classifier
RTAgent
Addr Classifier
RTR
RTR
Link n0-n1
entry_
entry_
Link n1-n0
6
The approach

• In order to have the desired behavior,we
  introduce
• RTModule. This is responsible to register the
  classifier, routing module used by the node.
• RTClassifier. Its function is to forward every
  incoming packet to the RTAgent, this adds an
  additional delay in the packet flow due to the
  presence of CPU load.

Node
Node
MultiHop Extension
RTAgent
RTAgent
AODV RTR
AODV RTR
Hash Classifier
RTMobile Classifier
WSNModule
RTModule/Base
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Packet Flow with MultiHop Extension
Source
Gateway
Destination
n2
n0
n1
RT App
RT App
Port Classifier
Port Classifier
RTAgent
Addr Classifier
RTAgent
Addr Classifier
RTR
RTR
Link n0-n1
entry_
entry_
Link n1-n0
8
Validation

• Result obtained by running the simulation before
  and after extension.

Line Fetch Forward
Ns-2 Trace file for a Simulation run
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Simulation I

• Fetch Forward with a line topology

1
3
4
2

• Node 1, 2 Source
• Node 3 Gateway
• Node 4 Destination
• Phy/Mac 802.15.4
• AODV Routing
• CBR Trafic 5Hz.
• 0 lt Load lt 1 on Gateway.

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Simulation II

• Peer to Peer with distributed load topology

• 25 Nodes. 5050 sq m.
• Phy/Mac 802.15.4
• AODV Routing
• CBR Trafic 5Hz. Node 19 -gt Node 6

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Simulation III

• Beacon Enabled Tree

• 11 Nodes. 5050 sq m.
• PAN Coordinator 1
• Coordinator 5
• Devices 5
• Phy/Mac 802.15.4
• Beacon Mode- Enabled
• Beacon Order 3
• Superframe Order 3
• AODV Routing
• CBR Trafic 5Hz. Node 1-gt Node 6

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Simulation IV

• Effect of Node Failure on Beacon Enabled Tree

• 11 Nodes. 5050 sq m.
• PAN Coordinator 1
• Coordinator 5
• Devices 5
• Phy/Mac 802.15.4
• Beacon Mode- Enabled
• Beacon Order 3
• Superframe Order 3
• AODV Routing
• CBR Trafic 5Hz. Node 1-gt Node 6

13
Conclusions

• A tool to simulate operating system aspects in
  wireless sensor network.
• A releastic evaluation of packet latency.
• Comparision of FCFS policy vs FP policy.
• A rapid prototype suite which will help to
  compare the simulation results with actual
  hardware implementation.