Bulk-n-Pick Method for One-to-Many Data Transfer in Dense Wireless Spaces

in Dense Wireless Spaces

Marat Zhanikeev [email protected] 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

.

The Problem

M.Zhanikeev -- [email protected] Bulk-n-Pick Method for One-to-Many Data Transfer in Dense Wireless Spaces -- bit.do/160724 2/18...

2/18

.

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


3/18

.

The Problem : Overhead Calculator


4/18

.

The Problem : Experiments

1

2

3

5

10

No.

of t

ries t

hres

hold

gap#0 tag#tabletsonly gap#5 tag#all gap#0 tag#all

0 20 40 60 80 100Probability

10

50

100

200

500

1000

2000

5000

10000

25000

50000

Com

plet

ion

time

thre

shol

d (m

s)

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 100Probability

0 20 40 60 80 100Probability


5/18

.

The Solution


6/18

.

The Solution : Push, not Pull

Server Client

…….

Server Client

…….

Pull

Push


7/18

.

The Solution : Pull vs Push (tests)

2.4 3.2 4 4.8log( chunksize)

1.61.8

22.22.42.62.8

3lo

g( th

roug

hput

)

pushpush.worker.pass.by.refpush.worker.pass.by.copyPush/pull ratio

Streams[1]


1.6

2

2.4

2.8

3.2

log(

pus

h/pu

ll rat

io)

Streams[1]


1.61.8

22.22.42.62.8

3

log(

thro

ughp

ut)

Streams[2:5]


1.6

2

2.4

2.8

3.2

log(

pus

h/pu

ll rat

io)

Streams[2:5]


1.61.8

22.22.42.62.8

3

log(

thro

ughp

ut)

Streams[7:10]


1.6

2

2.4

2.8

3.2

log(

pus

h/pu

ll rat

io)

Streams[7:10]


8/18

.

The Solution : Circuits vs Packets2 flows

.....L1

L15

2 flows

15 links

30 flows ...

• the old circuits vspackets problem

• intuition for LANs/WLANs◦ under low-volume traffic,

packets are better◦ under bulk/bigdata traffic,circuits are better


9/18

.

The Solution : Circuits = Scheduling

Line =

outgoing

port

Overhead = contention

No. of flows

Line =

outgoing

port

Overhead

Scheduling

Traditional

Circuits


10/18

.

The Proposal


11/18

.

Proposal : Bulk-n-Pick Method

Network(wireless)

User device(browser)

AJAX

Timeorder Web

server

WiFi

…..

Bulkstep

Pickstep

Store bulk(Javascript variable)


12/18

.

Proposal : Setup/Modeling

• use experiments (above) as numeric models• emulate a wider range of conditions and see how Bulk-n-Pickperforms


13/18

.

Proposal : Results (1/2)

0 2 4 6 8 10 12 14 16 18Ordered list

0

500

1000

1500

2000

2500

3000

3500

4000

Com

plet

ion

time

(sec

ond

s)

TraditionalBulk-n-pick (proposal with 2 concurrent bulks)


14/18

.

Proposal : Results (2/2)

0 2 4 6 8 10Number of parallel Bulk-n-Pick sessions

0

1000

2000

3000

4000

5000

6000

7000

Fina

l com

plet

ion

time

(sec

ond

s)

TraditionalBulk-n-pick (proposed)


15/18

.

Wrapup


16/18

.

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 andbuilds 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 -- [email protected] Bulk-n-Pick Method for One-to-Many Data Transfer in Dense Wireless Spaces -- bit.do/160724 17/18...

17/18

https://github.com/maratishe/msaplayer

.

That’s all, thank you ...


18/18

Technology

Bulk-n-Pick Method for One-to-Many Data Transfer in Dense Wireless Spaces