Transcript Multipoint QoS measurements

Multipoint QoS Measurements with QoSMeT
Pekka Perälä, Jarmo Prokkola and Marko Jurvansuu
Converging Networks Laboratory - VTT
[email protected]
Tel: +358 400 989 353
P.O. Box 1100 (Street: Kaitoväylä 1, Oulu)
FI-90571 Oulu, Finland
23.09.2008
VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Contents
•
•
•
•
•
Introduction
Overview of QoS Measurement Tool (QoSMeT)
The multipoint measurements with QoSMeT
Measurement examples
Conclusions
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Introduction (1)
• Real-time applications demand high quality from the network (low delay, low
jitter, low packet loss, etc.)
• High available BW does not always ensure QoS
• Many methods reveal the overall performance of the network, but it does not
necessary reflect well on how the individual applications behave.
 It is important to find out the QoS metrics of a single application
• The passive E2E QoS measurements reveal the QoS experienced by an
application
• VTT's QoSMeT tool measures one-way QoS metrics
• For e.g. SLA verification
• However, E2E measurement is not able to locate the problematic link, it only
can indicate that a performance problem exists
 One solution to the problem is multipoint measurement that reveals
the performance on per network segment basis.
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Introduction (2)
• Multipoint QoS measurements are continuation to the development work of
QoSMeT (ITEA Easy wireless & Celtic Easy Wireless 2)
• Objective is to maintain QoS while roaming over heterogeneous
networks
• The implemented demonstrator integrates traditional network analyzer and
E2E QoS measurement
• QoSMeT and multipoint measurement systems have been tested not only in
controlled environment, but also in public networks (HSPA, public Wi-Fi,
WiMAX, etc.)
• M. Jurvansuu, J. Prokkola, M. Hanski, P. Perälä, ”HSDPA Performance in Live
Networks,” In proceedings of IEEE International Conference on Communications
(ICC 2007).
• Our Converging Networks Laboratory (CNL) has been the main facility for
the tests in addition to public networks
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QoSMeT Overview (1)
• QoSMeT is a passive tool software for measuring one-way end-to-end
network performance in real-time from the application’s point of view
• Designed for measuring especially real-time applications (e.g., VoIP,
video conferencing), but other networking applications can be measured
as well.
• The tool works practically over any kind of network as long as IP is
supported
• No additional hardware
• One-way delay measurements require GPS time stamping (…and
GPS equipment)
• Win32 platform (Linux is coming)
J. Prokkola, M. Hanski, M. Jurvansuu, M. Immonen, ”Measuring WCDMA and HSDPA
Delay Characteristics with QoSMeT,” In proceedings of IEEE International
Conference on Communications (ICC 2007).
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QoSMeT Overview (2)
•A separate TCP connection is used for carrying
the QoSMeT control data over the network if realtime mode is used
•Application is not aware of the measurement
•Records in real-time:
•Average QoS statistics
•Accurate per packet statistics
•The most important measured QoS metrics
• Delay
• Jitter (average and absolute)
• Packet loss
• The length of a connection break (for example
during a vertical handover)
• Traffic statistics
• Pseudo-subjective analysis: VoIP MOS (Mean
Opinion Score) quality
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QoSMeT Measurement Examples:
WCDMA and HSPA Delay and Goodput Performance
0.5
WCDMA UL
0.45
WCDMA DL
0.4
Delay [s]
0.35
0.3
10 000 000
0.25
0.2
0.15
1 000 000
0.05
0
0.0
100.0
0.5
200.0
300.0
400.0
Measurement duration [s]
500.0
600.0
Goodput [bit/s]
0.1
100 000
UDP: HSDPA
10 000
UDP: HSUPA
LAN (limited)
0.45
HSPA (mean)
0.4
HSDPA (2006)
1 000
Delay [s]
WCDMA (2006)
0.35
HSUPA
0.3
HSDPA
HSPA (first conn, mean)
100
10
0.25
100
1000
10000
100000
1000000
10000000
Download file size [B], (UDP packet size)
0.2
J. Prokkola, P. Perälä, M. Hanski and E. Piri ” 3G/HSPA
Performance in Live Networks from the End User Perspective
,” submitted to IEEE ICC2009
0.15
0.1
0.05
0
0.0
100.0
200.0
300.0
400.0
Measurement duration [s]
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500.0
600.0
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Multipoint Measurement Principle
• Multipoint measurements help to locate the performance bottlenecks by
revealing the QoS of each network segment
• P. Perälä, M. Jurvansuu, J. Prokkola, ”Combined Terminal and Network Measurement
System for Bottleneck Localization,” In proceedings of Tridentcom 2008
• The traffic is captured from several (> 2) measurement points (MP), where
the traffic is captured
• The one-way performance can be split to the performance of network
segments based on the captured data
 The segment with the poorest performance can be found
According to multipoint measurement principle the network
performance is divided into performances of network segments
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Multipoint measurement system
• GPS timestamping enables
breaking-down the one-way
delays
• Integration of QoSMeT and
Nethawk M5 analyzer
• Each measurement point captures
the data of interest (generated by
single or multiple applications)
Multipoint measurement system applied to
UMTS.
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Public Wi-Fi network multipoint measurements (1)
• Conducted in panOulu, a
city-wide WLAN (802.11g)
network
• Three measurement points
(two QoSMeTs and a
commercial network
analyzer)
• One-way delay, access
network delay and Internet
delay were calculated
• Packet loss was found
interesting too
• UDP streams of different
rates
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Figure 9. panOulu measurement setup.
Average
delay
E2E
delay
(ms)
Access
networ
k
(ms)
Internet
(ms)
14.49
2.85
11.64
Figure 10. One-way delay statistics for VoIP call (steady state
performance)
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Public Wi-Fi network measurements (2)
• In steady state the Internet delay is
dominating (Fig. 12)
• After max bandwidth (< 10 Mbps) is
exceeded, E2E delay increases
due to the access network
• When access point starts
discarding packets it causes
increased E2E packet loss
• Internet delay is quite constant with
all loads and packet loss negligible
• The access network is the
bandwidth bottleneck and also the
on with longest delay in stress
situations
Figure 11. PanOulu delay performance with 16 Mbps offered
load.
Figure 12. Average delays and packet loss
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Conclusions & Future Work
• QoSMeT enables QoS measurement of IP networks from single
applications point of view
• With multipoint measurement systems it is possible to locate
performance bottlenecks in IP networks
• The multipoint measurement system combined terminal and
intermediate point measurement
• The work is continued in Celtic Easy Wireless 2 project
• Kick-off meeting 23-24 of September
• Light-weight measurement agents to the network for multipoint
measurements
• The amount of measurement data that is collected and processed
in real-time becomes problematic
• Application adaptation based on QoS measurements (e.g., SVC)
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References
[ref1] J. Prokkola, M. Hanski, M. Jurvansuu, M. Immonen,
”Measuring WCDMA and HSDPA Delay Characteristics with
QoSMeT,” In proceedings of IEEE International Conference on
Communications (ICC 2007).
[ref2]
M. Jurvansuu, J. Prokkola, M. Hanski, P. Perälä, ”HSDPA
Performance in Live Networks,” In proceedings of IEEE
International Conference on Communications (ICC 2007).
[ref3]
P. Perälä, M. Jurvansuu, J. Prokkola, ”Combined Terminal
and Network Measurement System for Bottleneck Localization,” In
proceedings of Tridentcom 2008.
[ref4]
J. Prokkola, P. Perälä, M. Hanski and E. Piri, “3G/HSPA
Performance in Live Networks from the End User Perspective”
submitted to IEEE ICC2009.
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Benefits
• Practical, hands-on work with
new technologies and prototypes
• Innovation for new product
development
• New possibilities for
testing and prototyping on a live,
"clean" and highly configurable
network
Convergent network and service infrastructure that
supports company R&D with applied research
Co-operation
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funded projects
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projects (EU/IST, Tekes, ITEA)
• Licensing of VTT software
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part of the CNL infrastructure
Offerings
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