Comparison of Multiplexing Policies for FPS Games in terms of Subjective Quality
43
COMPARISON OF MULTIPLEXING POLICIES FOR FPS GAMES IN TERMS OF SUBJECTIVE QUALITY GTC Technologies Group Communication Jose Saldana Julián Fernández-Navajas José Ruiz-Mas Luis Sequeira Luis Casadesus University of Zaragoza, Spain
-
Upload
jose-saldana -
Category
Education
-
view
100 -
download
6
description
Jose Saldana, Julian Fernandez Navajas, Jose Ruiz Mas, Luis Sequeira, Luis Casadesus, "Comparison of Multiplexing Policies for FPS Games in terms of Subjective Quality". Proc. II Workshop on Multimedia Data Coding and Transmission 2012, Jornadas Sarteco. Elche (Spain). Sept. 2012. ISBN: 978-84-695-4472-3
Transcript of Comparison of Multiplexing Policies for FPS Games in terms of Subjective Quality
COMPARISON OF MULTIPLEXING POLICIES FOR
FPS GAMES IN TERMS OF SUBJECTIVE QUALITY
GTCTechnologies GroupCommunication
Jose Saldana Julián Fernández-Navajas
José Ruiz-Mas Luis Sequeira
Luis Casadesus University of Zaragoza, Spain
Index - I. Introduction
- II. Test Methodology
- III. Tests and Results
- IV. Conclusions
Index - I. Introduction
- II. Test Methodology
- III. Tests and Results
- IV. Conclusions
Introduction - Online games are getting very
popular in the last years
Introduction
Real-time strategy Sports
MMORPG FPS
Introduction - First Person Shooters: the ones
with the tightest real-time requirements (video)
Introduction - Gamers: Very difficult customers
to deal with
Introduction Delay: Very important
Also:
Jitter
Packet loss
Introduction Scenarios where a number of players share the same connection
Central
Server
Multiplexer
TCM
TCM
Multiplexer
.
.
. Game
Server
Players
Access
routerMultiplexer
TCM
Introduction By multiplexing, we can save
- Bandwidth
- Packets per second
IP network
MUX DEMUX.
.
.
IP TCM IP
Game Server
Players
delaymux delayrouter delaynetwork
router
Introduction Adaptation of an RTP VoIP mux technique, to non-RTP flows
PPP
PPP Mux
ECRTP
payload
IP
UDP
RTP...
ECRTP
payload
L2TP
IP
One IPv4/UDP/RTP VoIP packet with two samples of 10 bytes
η=20/60=33%
Five IPv4/UDP/RTP VoIP packets with two samples of 10 bytes
η=20/60=33%
saving
VoIP
One IPv4 TCMTF Packet multiplexing five two sample packets
η=100/161=62%
40 to 6-8 bytes compression
Introduction Adaptation of an RTP VoIP mux technique, to non-RTP flows
PPP
PPP Mux
Reduced Header
Payload
IP
UDP...Reduced Header
Payload
L2TP
IP
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%
Introduction Significant savings:
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
Introduction By multiplexing, we can save
- Bandwidth
- Packets per second
… at the cost of adding
- Delay
- Jitter IP network
MUX DEMUX.
.
.
IP TCM IP
Game Server
Players
delaymux delayrouter delaynetwork
router
Introduction Two policies to define which packets are multiplexed
1) period
2) timeout
PE
. . .
. . .
. . .
. . .
Native
traffic
Multiplexed
traffic
PE PE PE
TO
. . .
. . .
. . .
. . .
TONative
traffic
Multiplexed
traffic
Introduction Expected results:
Period
- Smaller savings
- Less jitter
Timeout
- Higher savings
- Higher additional jitter
PE
. . .
. . .
. . .
. . .
Native
traffic
Multiplexed
traffic
PE PE PE
TO
. . .
. . .
. . .
. . .
TONative
traffic
Multiplexed
traffic
Introduction In this work, we compare timeout and period policies, in terms of a subjective quality estimator.
Tradeoff: savings vs jitter
Index - I. Introduction
- II. Test Methodology
- III. Tests and Results
- IV. Conclusions
Test methodology - Traffic of the game
- Small packets (79.5 bytes avg)
- 64 pps
40 50 60 70 80 90 100 110bytes
0 10 20 30 40 50 60 70ms
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
delaymux delayrouter delaynetwork
router
Test methodology Buffer:
2 Mbps, drop-tail
byte-sized 10 kB (tiny)
Background traffic:
50% packets 40 bytes
10% packets 576 bytes
40% packets 1500 bytes
Test methodology
PE/TO ↑
BW↓
Mux delay and
jitter↑
Buffer delay and
jitter↓
IP network
MUX DEMUX.
.
.
IP TCM IP
Game Server
Players
delaymux delayrouter delaynetwork
router
Test methodology - 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. Packet loss is not considered under 35%.
Index - I. Introduction
- II. Test Methodology
- III. Tests and Results
- IV. Conclusions
0
5
10
15
20
25
30
5 10 15 20 25 30 35 40 45 50
ms
Period or timeout (ms)
Average Retention Time5 players TO
5 players PE
10 players TO
10 players PE
Tests and Results
5 and 10 players: TO adds more delay
0
5
10
15
20
25
30
5 10 15 20 25 30 35 40 45 50
ms
Period or timeout (ms)
Average Retention Time5 players TO
5 players PE
10 players TO
10 players PE
Tests and Results
Saturation: above 25 ms, a size of 1500 bytes is
reached, so the packet is sent
0
5
10
15
20
25
30
5 10 15 20 25 30 35 40 45 50
ms
Period or timeout (ms)
Average Retention Time15 players TO
15 players PE
20 players TO
20 players PE
Tests and Results
15 and 20 players: slight difference
Retention: T/2
0
200
400
600
800
1000
0 5 10 15 20
nu
mb
er
of
packets
Period (ms)
Retention time histogram PE=15ms
0
200
400
600
800
1000
0 5 10 15 20
nu
mb
er
of
packets
Timeout (ms)
Retention time histogram TO=15ms
Tests and Results
0
200
400
600
800
1000
0 5 10 15 20
nu
mb
er
of
packets
Period (ms)
Retention time histogram PE=15ms
0
200
400
600
800
1000
0 5 10 15 20
nu
mb
er
of
packets
Timeout (ms)
Retention time histogram TO=15ms
Tests and Results Tail above 15 ms: more jitter. No upper bound
for delay
Peak of 4119 packets: trigger
0
2
4
6
8
10
12
14
16
18
5 10 15 20 25 30 35 40 45 50
std
ev (
ms)
Period or Timeout (ms)
Retention Time stdev20 players PE
15 players PE
10 players PE
5 players PE
20 players TO
15 players TO
10 players TO
5 players TO
Tests and Results
0
2
4
6
8
10
12
14
16
18
5 10 15 20 25 30 35 40 45 50
std
ev (
ms)
Period or Timeout (ms)
Retention Time stdev20 players PE
15 players PE
10 players PE
5 players PE
20 players TO
15 players TO
10 players TO
5 players TO
Tests and Results
15 and 20 players: slight difference
5 and 10 players: higher
difference
Tests and Results Next tests:
- Background traffic
- 5 players
- 5, 15, 25 ms period / timeout
0
10
20
30
40
50
60
70
0 200 400 600 800 1000 1200 1400 1600 1800 2000
ms
background traffic (kbps)
RTT, Quake IV, 5 players, 10kB
TO=25ms 10kBPE=25ms 10kBTO=15ms 10kBPE=15ms 10kBTO=5ms 10kBPE=5ms 10kB
Tests and Results
0
10
20
30
40
50
60
70
0 200 400 600 800 1000 1200 1400 1600 1800 2000
ms
background traffic (kbps)
RTT, Quake IV, 5 players, 10kB
TO=25ms 10kBPE=25ms 10kBTO=15ms 10kBPE=15ms 10kBTO=5ms 10kBPE=5ms 10kB
Tests and Results
15 ms
25 ms
5 ms
timeout
period
TO presents a slightly higher delay
0
2
4
6
8
10
12
14
16
0 200 400 600 800 1000 1200 1400 1600 1800 2000
ms
background traffic (kbps)
jitter, Quake IV, 5 players, 10kB
TO=25ms 10kB
PE=25ms 10kB
TO=15ms 10kB
PE=15ms 10kB
TO=5ms 10kB
PE=5ms 10kB
Tests and Results
0
2
4
6
8
10
12
14
16
0 200 400 600 800 1000 1200 1400 1600 1800 2000
ms
background traffic (kbps)
jitter, Quake IV, 5 players, 10kB
TO=25ms 10kB
PE=25ms 10kB
TO=15ms 10kB
PE=15ms 10kB
TO=5ms 10kB
PE=5ms 10kB
Tests and Results
TO adds more jitter
1
1.5
2
2.5
3
3.5
4
0 200 400 600 800 1000 1200 1400 1600 1800 2000
MO
S
background traffic (kbps)
MOS, Quake IV, 5 players, 10kB
PE=5ms 10kB
TO=5ms 10kB
PE=15ms 10kB
TO=15ms 10kB
PE=25ms 10kB
TO=25ms 10kB
Tests and Results
1
1.5
2
2.5
3
3.5
4
0 200 400 600 800 1000 1200 1400 1600 1800 2000
MO
S
background traffic (kbps)
MOS, Quake IV, 5 players, 10kB
PE=5ms 10kB
TO=5ms 10kB
PE=15ms 10kB
TO=15ms 10kB
PE=25ms 10kB
TO=25ms 10kB
Tests and Results
PE is globally better. Smaller retention time and jitter are better than higher
bandwidth saving
Number of players MOSperiod MOStimeout Difference (%)
5 3.43 3.32 3.31 %
10 3.37 3.34 0.98 %
15 3.30 3.28 0.42 %
20 3.19 3.19 0.10 %
Tests and Results The difference can only be appreciated when the number of players is small
Index - I. Introduction
- II. Test Methodology
- III. Tests and Results
- IV. Conclusions
Conclusions - Two multiplexing policies have
been compared
- This comparison has to be done in terms of subjective quality, integrating all network parameters
- Timeout saves more bandwidth
- Period adds less delay and jitter
- MOS shows a slight advantage for period policy
- The difference can only be appreciated when the number of players is small
- The decision may also be influenced by implementation
Conclusions
