Influence of Online Games Traffic Multiplexing and Router Buffer on Subjective Quality

INFLUENCE OF ONLINE GAMES TRAFFIC MULTIPLEXING AND

ROUTER BUFFER ON SUBJECTIVE QUALITY

GTCTechnologies GroupCommunication

Jose Saldana Julián Fernández-Navajas

José Ruiz-Mas Eduardo Viruete Navarro

Luis Casadesus University of Zaragoza, Spain

Index - I. Introduction

- II. Related Works

- III. Test Methodology

- IV. Tests and Results

- V. Conclusions

CCNC 2012. DENVECT Workshop. Las Vegas Jan 14, 2012

Introduction - Online games are getting very

popular in the last years

- First Person Shooters are the ones with the tightest real-time requirements


Introduction FPS use a client-server architecture

Uplink bandwidth limit



Server processing capacity limit



Downlink bandwidth limit


“Shooting around the corner”

Jack Wang

Wang

Introduction



Jack

Wang: Dead

Wang

Wang

Introduction



Jack Wang

Wang: Dead ¡¡¡ #%$& !!!

Introduction


Introduction Main Key Performance Indicators (KPI):

- Delay

- Jitter

- Packet loss

.

.

. Game Server

Users

buffer

Internet

Router

Game &

background

traffic


Introduction Access networks: low-end routers, with limitations in:

- Bandwidth

- Packets per second

Different implementations

.

.

. Game Server

Users

buffer

Internet

Router

Game &

background

traffic


Introduction Scenarios where many users share a connection: we can multiplex packets from different players, and compress headers


Introduction By multiplexing, we can mitigate two problems:

- Bandwidth

- Packets per second

… at the cost of adding:

- Delay

- Jitter


- II. Related Works



- V. Conclusions

II. Related Works

- Multiplexing real-time flows

- Subjective quality evaluation

- Influence of the router buffer


Multiplexing real-time A multiplexer is introduced, and it also compresses headers

IP network

MUX DEMUX.

.

.

IP TCM IP

Game Server

Players

delaymux delayrouter delaynetwork

router


Multiplexing real-time First done for VoIP (RFC4170, “TCRTP”):

Adapted for non-RTP flows:

PPP

PPP Mux

Reduced Header

Payload

IP

UDP...Reduced Header

Payload

L2TP

IP

PPP

PPP Mux

ECRTP

payload

IP

UDP

RTP...

ECRTP

payload

L2TP

IP


Multiplexing real-time A period is defined, and all the packets arrived are compressed and multiplexed

PE

. . .

. . .

. . .

. . .

Native

traffic

Multiplexed

traffic

PE PE PE


Multiplexing real-time Efficiency improvement

One IPv4/TCP packet 1500 bytes

Four IPv4/UDP client-to-server packets of Counter Strike

One IPv4/TCM packet multiplexing four client-to-server Counter Strike packets

η=1460/1500=97%

η=61/89=68%

η=244/293=83%

One IPv4/UDP server-to-client packet of Counter Strike with 9 players

η=160/188=85%

saving

One IPv4/UDP/RTP packet of VoIP with two samples of 10 bytes

η=20/60=33%


Multiplexing real-time Significant savings (Counter Strike)

0%

5%

10%

15%

20%

25%

30%

35%

5 10 15 20 25 30 35 40 45 50

BS

period (ms)

Bandwidth Saving

20 players

15 players

10 players

5 players


Multiplexing real-time Significant savings (Counter Strike)

0

100

200

300

400

500

600

native 5 10 15 20 25 30 35 40 45 50

pp

s

period (ms)

Packets per second

20 players

15 players

10 players

5 players

II. Related Works





Multiplexing real-time - E-Model: VoIP delay and packet loss

- FPS games: different studies consider delay limits, and also packet loss limits

- G-Model: MOS formula for Quake IV, adapted from E-Model: delay and jitter

II. Related Works





Multiplexing real-time - Buffer size

- Bandwidth-delay product

- Stanford model

- Tiny buffer

- Buffer implementation

- Byte sized

- Packet sized

- Buffer limitations

- Maximum pps amount


- II. Related Works



- V. Conclusions


Test methodology - Simulation scenario:

- Traces of gaming traffic

- Background traffic

- RTT delay: sum of the delays

IP network

MUX DEMUX.

.

.

IP TCM IP

Game Server

Players


router


Test methodology Jitter: Multiplexing increases it

PE

. . .

. . .

. . .

. . .

Native

traffic

Multiplexed

traffic

PE PE PE

12/PEstdevmux

Different added delays


Test methodology

PE ↑

BW↓

Mux jitter↑

Buffer jitter↓

IP network

MUX DEMUX.

.

.

IP TCM IP

Game Server

Players


router


Test methodology Jitter has to be added in a proper way (Network jitter is considered independent)

rmroutermuxroutermux stdevstdevstdev cov22

IP network

MUX DEMUX.

.

.

IP TCM IP

Game Server

Players


router

22networkroutermuxtotal stdevstdevstdev


- II. Related Works



- V. Conclusions


Tests and Results Buffer: Drop-tail, 2 Mbps

byte-sized packet-sized

small 10 kB 16 packets

big 100 kB 166 packets

Buffers are equivalent, considering average packet size = 600 bytes


Tests and Results Game: Quake IV, 20 players

64 pps

79.5 bytes Native: 40.7 kbps x 20 players = 814 kbps

Multiplexed PE=5ms: 631 kbps 395 bytes

Multiplexed PE=15ms: 605 kbps 1,118 bytes


Tests and Results: delay

0

100

200

300

400

500

600

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ms

background traffic (kbps)

RTT, Quake IV, 10kB, 100kB

native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB

0

100

200

300

400

500

600

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ms


RTT, Quake IV, 16pack, 166 pack

native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack




0

100

200

300

400

500

600

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ms



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB

0

100

200

300

400

500

600

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ms



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack


Bandwidth limit native ≈ 1200 kbps

Bandwidth limit mux ≈1400 kbps



0

100

200

300

400

500

600

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ms



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB

0

100

200

300

400

500

600

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ms



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack


Buffer delay is constant Buffer delay varies as packet size increases



0

100

200

300

400

500

600

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ms



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB

0

100

200

300

400

500

600

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ms



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack


Small buffers introduce small delays


0

20

40

60

80

100

120

140

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ms


jitter, Quake IV, 10kB, 100kB

native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB

Tests and Results: jitter


0

20

40

60

80

100

120

140

0 200 400 600 800 1000 1200 1400 1600 1800 2000m

sbackground traffic (kbps)

jitter, Quake IV, 16pack, 166 pack

native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack


0

20

40

60

80

100

120

140

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ms



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB



Bandwidth limit native ≈ 1200 kbps

0

20

40

60

80

100

120

140

0 200 400 600 800 1000 1200 1400 1600 1800 2000m



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack

Bandwidth limit mux ≈1400 kbps


0

20

40

60

80

100

120

140

0 200 400 600 800 1000 1200 1400 1600 1800 2000m



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack

0

20

40

60

80

100

120

140

0 200 400 600 800 1000 1200 1400 1600 1800 2000

ms



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB



Average size of sent packets is bigger for packet-sized buffer, so jitter decreases

Big packets have a bigger dropping probability

All packets have the same dropping probability


0%

5%

10%

15%

20%

25%

30%

35%

0 200 400 600 800 1000 1200 1400 1600 1800 2000%

pa

ck

et

los


packet loss, Quake IV, 16pack, 166 pack

native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack

0%

5%

10%

15%

20%

25%

30%

35%

0 200 400 600 800 1000 1200 1400 1600 1800 2000

%p

ac

ke

t lo

ss


packet loss, Quake IV, 10kB, 100kB

native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB

Tests and Results: loss



0%

5%

10%

15%

20%

25%

30%

35%

0 200 400 600 800 1000 1200 1400 1600 1800 2000%

pa

ck

et

los



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack

0%

5%

10%

15%

20%

25%

30%

35%

0 200 400 600 800 1000 1200 1400 1600 1800 2000

%p

ac

ke

t lo

ss



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB



Small buffer starts loosing packets before

reaching the limit


0%

5%

10%

15%

20%

25%

30%

35%

0 200 400 600 800 1000 1200 1400 1600 1800 2000%

pa

ck

et

los



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack

0%

5%

10%

15%

20%

25%

30%

35%

0 200 400 600 800 1000 1200 1400 1600 1800 2000

%p

ac

ke

t lo

ss



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB



PE=15 obtains the worst results, because of

packet size (1,118 bytes)


0%

5%

10%

15%

20%

25%

30%

35%

0 200 400 600 800 1000 1200 1400 1600 1800 2000%

pa

ck

et

los



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack

0%

5%

10%

15%

20%

25%

30%

35%

0 200 400 600 800 1000 1200 1400 1600 1800 2000

%p

ac

ke

t lo

ss



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB



Worse results for packet-sized, because all the packets have the

same discarding probability


0%

5%

10%

15%

20%

25%

30%

35%

0 200 400 600 800 1000 1200 1400 1600 1800 2000%

pa

ck

et

los



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack

0%

5%

10%

15%

20%

25%

30%

35%

0 200 400 600 800 1000 1200 1400 1600 1800 2000

%p

ac

ke

t lo

ss



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB



For packet-sized buffer, packet loss is significantly reduced when

multiplexing


1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000M

OS


MOS, Quake IV, 16pack, 166 pack

native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack

1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000

MO

S


MOS, Quake IV, 10kB, 100kB

native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB

Tests and Results: MOS


MOS is based on delay and jitter


1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000M

OS



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack

1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000

MO

S



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB



Small buffers: graphs go down, and grow a little

when jitter peak goes down


1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000M

OS



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack

1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000

MO

S



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB



Multiplexing allows more background traffic


1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000M

OS



native 16pack

PE=5ms 16pack

PE=15ms 16pack

native 166pack

PE=5ms 166pack

PE=15ms 166pack

1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000

MO

S



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB



Multiplexing results are worse than native


1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000

MO

Sbackground traffic (kbps)


native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB

byte-sized byte-sized pps limit

2,000 pps (maximum 1,652 offered)

1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000

MO

S



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB



1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000

MO

Sbackground traffic (kbps)


native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB

1

1.5

2

2.5

3

3.5

4

4.5

5

0 200 400 600 800 1000 1200 1400 1600 1800 2000

MO

S



native 10kB

PE=5ms 10kB

PE=15ms 10kB

native 100kB

PE=5ms 100kB

PE=15ms 100kB


byte-sized byte-sized pps limit

This limitation has a very bad effect on MOS.

Multiplexing alleviates it


- II. Related Works



- V. Conclusions


Conclusions - The mutual influence of the

buffer router and multiplexing has been studied

- Small buffers are more adequate to reduce delay and jitter

- Packet-sized buffers increase packet loss, and multiplexing alleviates this


Conclusions - Multiplexing always saves

bandwidth

- In packet-sized buffers, multiplexing does not improve experienced quality

- Multiplexing is very interesting when a limit in pps is present

THANK YOU

GTCTechnologies GroupCommunication [email protected]

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Influence of Online Games Traffic Multiplexing and Router Buffer on Subjective Quality

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