The document proposes a Bulk-n-Pick method for one-to-many data transfer in dense wireless spaces. It begins by outlining problems with congested WiFi networks and inefficient HTTP requests. The solution involves pushing data to clients using circuits rather than individual packet pulls, which reduces overhead. The Bulk-n-Pick method bulk transfers data then allows clients to pick relevant portions, improving throughput. Modeling suggests it completes transfers much faster than traditional methods, especially with multiple parallel sessions. The approach reintroduces benefits of circuits for bulk data transfer over wireless networks.

1. in Dense Wireless Spaces
Marat Zhanikeev
maratishe@gmail.com
maratishe.github.io
2016/07/24@NANA@Hakodate
Bulk-n-Pick Method
PDF: bit.do/160724
for One-to-Many Data Transfer
#densewireless
#bulktransfer #sync
#congestion
#websockets
#html5

2. .
The Problem
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3. .
The Problem
• WiFi networks are badly congested -- dense wireless spaces
◦ as a side effect: LAN hubs have removed CSMA in modern hubs/switches, but no in
WLANs
◦ distance effect is huge: farther = slower (rates) = takes longer = increases
congestion
• webapps served over WiFi need to be rewritten
◦ when congested, HTTP requests come back empty -- JS side should
have additional logic for repeated requests (resilience)
• educational classes have considerable bulk of content -- heavy WiFi users
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4. .
The Problem : Overhead Calculator
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5. .
The Problem : Experiments
1
2
3
5
10
No.oftriesthreshold
gap#0 tag#tabletsonly gap#5 tag#all gap#0 tag#all
0 20 40 60 80 100
Probability
10
50
100
200
500
1000
2000
5000
10000
25000
50000
Completiontimethreshold(ms)
gap#0 tag#tabletsonly gap#5 tag#all gap#0 tag#all
Size#100000Size#10000Size#100
~40% take 3+ tries
~40% take 10s or more
0 20 40 60 80 100
Probability
0 20 40 60 80 100
Probability
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6. .
The Solution
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7. .
The Solution : Push, not Pull
Server
Client
…….
Server
Client
…….
Pull
Push
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8. .
The Solution : Pull vs Push (tests)
2.4 3.2 4 4.8
log( chunksize)
1.6
1.8
2
2.2
2.4
2.6
2.8
3
log(throughput)
push
push.worker.pass.by.ref
push.worker.pass.by.copy
Push/pull ratio
Streams[1]
2.4 3.2 4 4.8
log( chunksize)
1.6
2
2.4
2.8
3.2
log(push/pullratio)
Streams[1]
2.4 3.2 4 4.8
log( chunksize)
1.6
1.8
2
2.2
2.4
2.6
2.8
3
log(throughput)
Streams[2:5]
2.4 3.2 4 4.8
log( chunksize)
1.6
2
2.4
2.8
3.2
log(push/pullratio)
Streams[2:5]
2.4 3.2 4 4.8
log( chunksize)
1.6
1.8
2
2.2
2.4
2.6
2.8
3
log(throughput)
Streams[7:10]
2.4 3.2 4 4.8
log( chunksize)
1.6
2
2.4
2.8
3.2
log(push/pullratio)
Streams[7:10]
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9. .
The Solution : Circuits vs Packets
2 flows
.....
L1
L15
2 flows
15 links
30 flows ...
• the old circuits vs
packets problem
• intuition for LANs/WLANs
◦ under low-volume traffic,
packets are better
◦ under bulk/bigdata traffic,
circuits are better
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10. .
The Solution : Circuits = Scheduling
Line=
outgoing
port
Overhead =
contention
No. of flows
Line=
outgoing
port
Overhead
Scheduling
Traditional
Circuits
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11. .
The Proposal
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12. .
Proposal : Bulk-n-Pick Method
Network
(wireless)
User device
(browser)
AJAX
Time
order
Web
server
WiFi
…..
Bulk
step
Pick
step
Store bulk
(Javascript variable)
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13. .
Proposal : Setup/Modeling
• use experiments (above) as numeric models
• emulate a wider range of conditions and see how Bulk-n-Pick
performs
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14. .
Proposal : Results (1/2)
0 2 4 6 8 10 12 14 16 18
Ordered list
0
500
1000
1500
2000
2500
3000
3500
4000
Completiontime(seconds)
TraditionalBulk-n-pick (proposal with 2 concurrent bulks)
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15. .
Proposal : Results (2/2)
0 2 4 6 8 10
Number of parallel Bulk-n-Pick sessions
0
1000
2000
3000
4000
5000
6000
7000
Finalcompletiontime(seconds)
Traditional
Bulk-n-pick (proposed)
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16. .
Wrapup
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17. .
Wrapup: The Bigger Picture
• this paper builts up on 01, and tests in https://github.com/maratishe/msaplayer
• but Bulk-n-Pick model is a bigger concept that brings back circuits and
builds a new webapp logic around them
Network
Web Server
Chrome Browser
Control
…….
Buffer
User
WebSocket
WebWorker
WebSocket
WebWorker
WebSocket
Server
WebSocket request
fork()
Handshake
01 M.Zhanikeev+0 "Experiments with application throughput in a browser with full HTML5 support" IEICE ComEx (2013)M.Zhanikeev -- maratishe@gmail.com Bulk-n-Pick Method for One-to-Many Data Transfer in Dense Wireless Spaces -- bit.do/160724 17/18
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18. .
That’s all, thank you ...
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