Implementation of Overlay Network in NS

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Implementation of Overlay Network in NS

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• 19991260
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Approach and Goal

• Implement Overlay Network For Bandwidth
  Maintenance.
• Simulate Overlay Network Model in NS2.

Simulation
Confirm the Best Overlay Network Model!!!
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Overlay For Bandwidth

• Bandwidth is the basis for service.
• The smallest bandwidth between the hops.
• Persistent on several application.
• Ex Many P2P Application(Pruna, Soribada)

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Bandwidth and QOS

• Delay 150msec can be detected by humans.
• Minimize primarily the network latency.
• The tolerant of audio degradation is less than
  the tolerant of video degradation.
• Difficult for QOS compared to the data size.
• Minimize the packet loss as much as possible

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NS2

• Scenario Based
• Make various environments which I want
• Reenact the real situation
• Simulation
• Use the real protocol
• Consider all conditions OSI Layer 17
• Various ways to show the result

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NS2(cont)
NAM
XGraph
TCL (Scenario) Make condition and function
TCL(Module) Interface with C Object
C - Implementation
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Design
Implement the detailed process
TCL
Agent Interface for Node
Module Interface for Routing
C
Retransmission Manager
QOS Routing Node
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Implementation

• QOS Routing Node In NS2
• Base foundation
• Routing Algorithm
• Retransmission Manager
• Medium Layer
• Encapsulate the function in base foundation.
• Make command for scenario.
• Scenario
• Implement the detailed function.
• Write test scenario

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QOS Routing Algorithm

• Function
• Find the biggest bandwidth path.
• Table has the minimum bandwidth along the path.
• Not consider the delay from multi-hop path.
• Limit within 16 hops and use in specialized
  condition.
• Store the selective roads.
• The biggest bandwidth path in same hop.
• If the path has more hops, the bandwidth should
  be bigger.

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Create Session

• pseudo code for create path
• Get the explicit route path
• For each link
• Reserve the bandwidth
• Reveal bandwidth-change
• Create session and transmit data.

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QOS Routing Algorithm

• Pseudo Code For Compute the Road
• Algorithm From Node i to j over bandwidth
• Get the road table.
• Set minbw 0
• For each road to j
• check the bandwidth
• if the bandwidth is bigger than demand
• then
• accept the road and set minbw.
• Repeat compute steps by minbw until no road is
  found
• Return the road

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Test
2
4
BW 8
BW 5
1
BW 10
BW 7
BW 6
3
5
BW 8
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Test Result

• Normal Algorithm

• QOS Algorithm

Traffic
Packet Loss
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Conclusion

• Test the overlay network model.
• Algorithm works in the real condition.
• Minimize Packet loss
• Minimize Traffic
• Table updates whenever the value is changed.
• Bandwidth change
• Link status change
• Future consideration
• Consider the delay by multi-hop
• Test more complicate situation.