Yashar Ganjali, and Abtin Keshavarzian Presented by: Isaac Keslassy Computer Systems Laboratory...
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Transcript of Yashar Ganjali, and Abtin Keshavarzian Presented by: Isaac Keslassy Computer Systems Laboratory...
Yashar Ganjali, and Abtin KeshavarzianPresented by: Isaac Keslassy
Computer Systems LaboratoryDepartment of Electrical EngineeringStanford University
INFOCOM 2004
Load Balancing in Ad Hoc Networks:
Single-path Routing vs. Multi-path Routing
INFOCOM 2004 Load Balancing in Ad Hoc Networks 2
Outline
1. Single-path vs. multi-path routing2. Comparison Criteria3. Network model4. Traffic distribution analysis
4-1. Single-path routing4-2. Multi-path routing
5. Simulations6. Optimal number of paths?7. Conclusion
INFOCOM 2004 Load Balancing in Ad Hoc Networks 3
Single-path vs. Multi-path
s t
s t
Single-path routing
Multi-path routing
INFOCOM 2004 Load Balancing in Ad Hoc Networks 4
Comparison Criteria
Overhead: Route discovery overhead Route maintenance overhead Data transmission overhead
Load distribution (throughput)
INFOCOM 2004 Load Balancing in Ad Hoc Networks 5
Network ModelNodes: Distributed uniformly in a circle of radius one with density (high)Links: Any two nodes with distance <= T are connectedTraffic: Each node sends to any other node in the network with fixed rate
INFOCOM 2004 Load Balancing in Ad Hoc Networks 6
Problem Statement
Find the amount of flow going through a node (load) at
distance r from the center.
INFOCOM 2004 Load Balancing in Ad Hoc Networks 7
Any path starting at a node in S1 going to a node in S2 goes through node F.
Therefore, the traffic going through node F is proportional to S1 x S2.
S1
S2
Load Distribution Analysis:Single-path Routing
[P. Pham and S. Perreau, INFOCOM’03]
F
d
INFOCOM 2004 Load Balancing in Ad Hoc Networks 8
[Pham and Perreau, INFOCOM’03]: Load is distributed uniformly using multi-path routing.
Load Distribution Analysis: Multi-path Routing
0102030405060
0 250 350 500 750 1000 1250
Distance from the Origin
Lo
ad
Single-path routing Multi-path routing
INFOCOM 2004 Load Balancing in Ad Hoc Networks 11
Load Distribution Analysis
Problem: For a given node F in the network find the set of all node pairs (A,B) such that the rectangle defined by A and B contains F.
AF
B
INFOCOM 2004 Load Balancing in Ad Hoc Networks 13
Load Distribution Analysis
A F
B=(x,y)
d
L
y=L cosy=L sinL =d cosx=d cos2
y=d sin cosy2+(x-d/2)2=d2/4
INFOCOM 2004 Load Balancing in Ad Hoc Networks 15
Load Distribution Analysis
For a fixed node F, and and a given node A we can find all points B such that the traffic from A to B goes through F. If we sum up for all nodes A we can find the total traffic going through F.
F
A r
INFOCOM 2004 Load Balancing in Ad Hoc Networks 16
How to choose w?
It is inversely proportional to .It depends on how nodes are connected.It depends on how paths are chosen: Length metric: hop-count, Euclidian
distance. Edge-disjoint vs. node disjoint.
It is increased by the number of paths in multi-path routing.
INFOCOM 2004 Load Balancing in Ad Hoc Networks 17
How to choose w? (cont’d)
1. Keep all parameters fixed.2. Find w based on simulations for
single-path.3. For k paths use kw.
INFOCOM 2004 Load Balancing in Ad Hoc Networks 18
Evaluation of the Model
500 Nodes - 2 Paths
0.00
1000.00
2000.00
3000.00
4000.00
5000.00
0.1 0.2 0.3 0.4 0.4 0.5 0.6 0.7 0.8 0.9
Distance
Lo
ad Simulation
Analysis
INFOCOM 2004 Load Balancing in Ad Hoc Networks 19
Evaluation of the Model
500 Nodes - 4 Paths
0.00
2000.00
4000.00
6000.00
8000.00
10000.00
0.1 0.2 0.3 0.4 0.4 0.5 0.6 0.7 0.8 0.9
Distance
Lo
ad Simulation
Analysis
INFOCOM 2004 Load Balancing in Ad Hoc Networks 20
Evaluation of the Model
500 Nodes - 10 Paths
0
20000
40000
60000
80000
100000
120000
0.1 0.2 0.3 0.4 0.4 0.5 0.6 0.7 0.8 0.9
Distance
Lo
ad Simulation
Analysis
INFOCOM 2004 Load Balancing in Ad Hoc Networks 21
Effect of Increasing the Number of Paths in Multi-path routing
0
2
4
6
8
10
12
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Distance from the Center
No
rmal
ized
Lo
ad
2 Paths
4 Paths
10 Paths
20 Paths
50 Paths
100 Paths
200 Paths
INFOCOM 2004 Load Balancing in Ad Hoc Networks 22
Effect of Increasing the Number of Paths in Multi-path routing
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
Distance from the Center
Log(
Loa
d )
2 Paths
4 Paths
10 Paths
20 Paths
50 Paths
100 Paths
200 Paths
INFOCOM 2004 Load Balancing in Ad Hoc Networks 23
Summary We introduced a new method for analyzing the traffic in Ad Hoc Networks.Advantages of the new model: Works for both single-path and multi-path Sensitive to the number of paths
We showed that increasing the number of paths in multi-path routing does not dramatically affect the load balance in the network. Open problem: What if we route on curves instead of shortest paths?