HotNets'12 Access link can often be the bottleneck for application performance. In this paper, we propose to augment wired connections using cellular ones, that we term “3G onloading (3GOL)". 3GOL utilizes available mobile devices and alreadypaid-for data volumes to augment and improve performance of applications on wired network. We motivate 3GOL by understanding bottlenecks present in the wired and the cellular networks. In order to understand the potential benefits of 3GOL, we conduct active experiments using mobile devices. We show that capacity gains can scale linearly with the number of devices on the downlink while also seeing improvements on the uplink. Using real traces we show how video on demand can benefit with 3GOL, even when volume caps are in place. We design 3GOL as an over the top service, and highlight research challenges.

1. When David helps Goliath:
The case for 3G Onloading
Narseo Vallina-Rodriguez, Vijay Erramilli, Yan Grunenberger,
Laszlo Gyarmati, Nikos Laoutaris, Rade Stanojevic,
Dina Pagagiannaki
University of Cambridge
Telefonica Research / Telefonica Digital
HotNets 2012, Redmond, WA

2. David and Goliath
100x
Wired Network (DSL) Cellular Network
200m
5.8 Gbps downlink 47 Mbps downlink
2.3 Gbps uplink 5.6 Mbps uplink
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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3. Can David help Goliath?
YES!
¤ For 1 ADSLà the entire BS is not David
¤ For all ADSLs à David can become Goliath FOR SHORT
PERIODS OF TIME
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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4. 3G Onloading
¤ Offload traffic from the wired network onto the cellular
network
¤ Speed up wired connections
¤ Improve applications’ performance
¤ Limitations:
¤ 3GOL cannot assist all wired connections
¤ Cannot help applications at all times
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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5. Scenario 1: David helps Goliath
¤ Video-streaming
application
¤ Well provisioned area
4.7 Mbps
¤ Spare capacity on
A cellular network
¤ Powerboost
3.4 Mbps ¤ Use-and-release
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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6. Scenario 2: David becomes Goliath
¤ Constrained wired
networks
¤ Cellular network can
4.7 Mbps provide more capacity
than wired networks
A
2 Km
2.8 Mbps
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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7. Design Considerations
¤ The Network
¤ 3G throughput is highly variable
¤ Control-plane latency
¤ The User Economics: volume caps in data plans
¤ 40 % of the mobile users use less than 10% of their
cap
¤ The Service
¤ Network integrated service
¤ Over the top
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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8. Preliminary results
¤ How much additional throughput?
¤ Performance improvement?
¤ Increase in cellular traffic?
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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9. How much additional throughput?
Scenario Time DSL (d/u) Mbps
1. The Network
¤ Densely populated residential 1 am 3.44 / 0.30
area (city center)
¤ 3G throughput depends on a number of factors
¤ Limited 3G network backhaul capacity
2. Office area rush hour 4 pm 4.51 / 0.47
¤ Signaling delay
3. Residential Area in tourist 10 pm 6.72 / 0.84
¤ The Economics
hotspot
¤ Data volume caps
4. Sparsely populated residential 1 am 2.84 / 0.45
¤ The Service
area (suburbs)
¤ Network integrated service
5. Popular shopping center in peak 2 pm
¤ Over the top n/a
time
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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10. How much additional throughput?
Upstream Downstream
Upstream Upstream
Upstream
Aggregated Throughput (Kbps) Upstream
Upstream Downstream
Downstream Downstream
Downstream Downstream
15000
Aggregated Throughput (Kbps)
Aggregated Throughput (Kbps)
Aggregated Throughput (Kbps)
Aggregated Throughput (Kbps)
Aggregated Throughput (Kbps)
15000
15000 15000 1500015000
10000
10000
10000 10000 10000
10000
5000
5000 5000
5000 50005000
0
0 0 0 0 0
1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
1 2 7 8 9 4 5 7 8 9 Cluster Size 672 710 894 96 106 8 9 10 10
1 12 23 34 45 561 672 783 894 196 2 7 1 8 2 9 3 104 10 561 3 83 5 10 7
3 4 5 6 1 2 3 10 5 10 106 3 1 4 2 5 3 6 45 2 17 8 9 4 5 7 8 9
Cluster Size Size Cluster SizeSize
Cluster Size Cluster
Cluster
Densely location Location1 Residential Location3
Location2 Location4 Shopping
Location5
Office center
populated location Location2
location area.
Location1 Location3
Location2 Location1 Location3
location Location1 Location2 Location4
Location3 Location2 Location4
Location1 Location1 Location2
locationlocation Suburbs
Location3 Location5
Location4 Location3 Location5Location4Location5
Location5 Location4 Location5
area (city center)
area Tourist hotspot
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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11. How much additional throughput?
Scenario Time DSL (d/u) Cellular (d/u) 3GOL/DSL
Mbps Mbps (d/u)
1. Densely populated 1 am 3.44 / 0.30 4.37 / 1.64 2.3 / 6.5
residential area (city center)
2. Office area rush hour 4 pm 4.51 / 0.47 4.56 / 5.18 2.0 / 12.0
3. Residential Area in tourist 10 pm 6.72 / 0.84 1.92 / 1.53 1.3 / 2.8
hotspot
4. Sparsely populated 1 am 2.84 / 0.45 4.67 / 3.89 2.7 / 9.7
residential area (suburbs)
5. Popular shopping center in 2 pm n/a 5.31 / 2.64 n/a
peak time
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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12. Performance improvement:
Video-streaming
Empirical CDF Empirical CDF
1 1
0.9 0.9
0.8 0.8
50% of the videos
0.7 have a speed up factor 0.7
fraction of videos
fraction of users
0.6 of 10 and below 0.6
0.5 0.5
0.4 0.4
40% of users have a
speed up around 20%
0.3 0.3
0.2 0.2
0.1
Unlimited 0.1
Capped
0 0
0 5 10 15 20 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6
dsl/3GOL dsl/3GOl(40MB)
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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13. Increase in 3G traffic
5
10
3GOL(20Mb budget)
3GOL(Unlim)
load on nwk (Mbs) 4
10 Cell capacity
3 Overload
10
Available Bandwidth
2
10
1
10
0 2 4 6 8 10 12 14 16 18 20 22 24
time (5min bins)
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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14. Prototype implementation
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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15. Research challenges
¤ Decide when to use 3GOL
¤ Which apps and when!
¤ Use the right devices
¤ Cell Nets are best effort!
¤ Pre-fetching radio channel
¤ How much data to onload
¤ How to aggregate different connections:
¤ Same Wi-Fi AP
¤ ClubDSL [Mobicom 2011]
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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16. Related Work
¤ Wired networks performance.
¤ Sundaresan et al. Broadband internet performance: a view from the
gateway. ACM SIGCOMM 2011.
¤ Kreibich et al. NetAlyzr, IMC 2010
¤ 3G Offloading
¤ Badam et al. The hare and the tortoise: taming wireless losses by exploiting
wired eliability. In MobiHoc, 2011.
¤ Lee et al. Mobile data offloading: how much can wifi deliver? CoNext 2010
¤ Mobile networks
¤ Ha et al. Tube. ACM Sigcomm, 2012
¤ Huang et al. A close examination of performance and power
characteristics of 4G/LTE networks
¤ Qiang et al. Characterizing radio resource allocation for 3g networks
¤ Vallina-Rodriguez et al. Breaking for commercials (To appear) IMC 2012
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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17. Summary
¤ David can help Goliath
¤ Powerboost-like service
¤ Constrained wired networks
¤ Overhead in cellular network can be controlled
¤ Use and release
¤ Data caps
¤ Better performance expected with LTE deployment
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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18. Questions?
Narseo Vallina-Rodriguez
nv240@cam.ac.uk
University of Cambridge /
Telefonica Research
Narseo Vallina-Rodriguez, University of Cambridge/Telefonica Research, HotNets'12
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