ALABAMO: A LoAd BAlancing MOdel for RPL Tarcísio Bruno C. Oliveira, Pedro Henrique Gomes, Danielo G. Gomes, Bhaskar Krishnamachari
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Outline • Mo8va8on • Background and Problem Statement • Objec8ves • Proposal – ALABAMO: A LoAd BAlancing MOdel for RPL • Performance Evalua8on • Related Work • Conclusion 2
Mo8va8on • Energy is a constrained resource in Low-‐Power and Lossy Networks (LLNs) • RPL became the standardized IPV6 rou8ng protocol for LLNs in 2012 • The default RPL objec8ve func8on uses link quality as rou8ng criterion which can cause an unbalanced distribu8on of nodes 3
Mo8va8on • Unbalanced Network
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Background • RPL -‐ Rou8ng Protocol for LLNs – IPv6 support
– Tree-‐like topology – Network control messages (DIO, DAO, DIS)
– Each node has a rank
– The ranks are calculated using an ObjecSve Funcion (OF) 5
Background • Objec8ve Func8ons – OF0
• It uses hop-‐count as a rouSng metric
– Minimum Rank With Hystheresis Objec8ve Func8on (MRHOF)
• It chooses routes that minimize rouSng metrics as latency, hop-‐count and ETX (Expected Transmission Count)
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Background
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Problem Statement Sensor nodes that have links with beZer quality will forward more packet than others. Thus, their energy deple8on will be notably faster.
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Objec8ves
• Develop a mechanism based on RPL to force a homogeneous energy consump8on among the nodes • Extend the network life8me avoiding holes in the network
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Objec8ves • Balanced Network
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ALABAMO • It takes into account the traffic profile to avoid overloading the nodes with high-‐quality links: – Based on MRHOF;
– All nodes broadcast the number of transmiWed packets;
– Hystheresis mechanism to prevent fast fluctuaSons.
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ALABAMO • It defines two auxiliary constants for flexibility purpose: – ETX
• Max ETX Ra8o • ETX RaSo = ETX1/ETX2
– Sent packets
• Max Workload Ra8o • Workload RaSo = SENT_PKT1/SENT_PKT2
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ALABAMO
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ALABAMO
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Performance Evalua8on • Alabamo vs MRHOF¹ • 41 motes (Tutornet¹) • UDP packets every 30 seconds • Each experiment lasts for 2 hours and it was repeated 12 8mes
¹[Gnawali and Levis 2012] ²hWp://anrg.usc.edu/www/tutornet/ 15
Performance Evalua8on
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Performance Evalua8on • Parameters
– Max ETX RaSo equals to 80 and Max ETX RaSo equals to 90 – Max Workload RaSo equals to 70
• Metrics
– RouSng tree – Network delivery raSo – Energy consumpSon/network lifeSme – Parent switching 17
Performance Evalua8on • Rou8ng tree – A snapshot of the rouSng tree was taken every 30 minutes
Std devia8on
Avg. heaviest sub-‐ tree size
Std devia8on
4.00
4.93
18.00
0.12
ALABAMO-‐80
3.63
3.79
11.93
1.67
ALABAMO-‐90
3.64
3.34
10.33
1.23
Model
Avg. Sub-‐tree size
MRHOF
Table 1. Routing tree
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Performance Evalua8on • Network delivery ra8o
Figura 6. Packet Delivery Ratio
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Performance Evalua8on • Energy consump8on
Std devia8on
Avg. consump8on (most loaded node in mW)
Std devia8on
4.65
6.24
34.72
9.04
ALABAMO-‐80
4.07
3.08
16.69
3.70
ALABAMO-‐90
4.04
4.79
21.21
15.12
Model
Avg. consump8on (per node in mW)
MRHOF
Table 2. Energy Consumption
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Performance Evalua8on • Normalized Network life8me
Figure 7. Network Lifetime
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Performance Evalua8on • Parent switching – MaxWorkloadRaSo Model
Average number of parent switches (per node)
Std devia8on
MRHOF
0.30
0.69
ALABAMO-‐80
1.24
1.93
ALABAMO-‐90
0.59
1.25
Table 3. Parent switching
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Related Work • Hierarchical and centralized solu8ons • RPL-‐based solu8ons – An Energy Efficient and Reliable Composite Metric for RPL Organized Networks [Capone et al. 2014] – Improving the network lifeCme with energy-‐ balancing rouCng: ApplicaCon to RPL [Iova et al. 2014] – Queue UClizaCon based RPL for Load Balancing in Large Scale Industrial ApplicaCons [Kim, H.-‐S. 2015]
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Conclusion • 2-‐fold increase in network life8me • More balanced trees • Trade-‐off between network life8me and PDR • Prac8cal solu8on tested in real deployment • RPL-‐compa8ble and totally distributed 24
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Contact
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