ITU-T Kaleidoscope Conference
Innovations in NGN
TWO BUFFER MODEL-BASED QoS
ESTIMATION METHOD FOR 3G
WIRELESS IP NETWORKS IN
BULLET TRAINS
Gang Qin
The University of Tokyo
shin-gou@akg.t.u-tokyo.ac.jp
Geneva, 12-13 May 2008
Outline
Summary
The proposed measurement
The QoS estimation method
The experiment and result
Conclusions and Future Works
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Summary
We are aiming at improving transport layer
protocols over 3G wireless IP networks in highspeed mobile environment.
It is necessary to make a model of high-speed
mobile communication environment on the
simulator.
To do this, measurement of the communication quality
and the raw packet transmission characteristics of the
3G is necessary
We will introduce a two buffer model-based QoS
estimation method used to measure the raw
packet transmission characteristics of CDMA2000
1xEV-DO in bullet trains.
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Definition of communication quality and measurement
(ITU-T Recommendations)
・IP packet transfer delay (IPTD) ・IP packet delay variation (IPDV)
・IP packet loss ratio (IPLR)
・IP packet error ratio (IPER)
• One-way measurement
• The probe packet will be
•
•
•
•
UDP–echo based
Time-stamped at injection
and extraction devices
Probe Packet
Results
MP A
MP B
The measurement points (MP) are fixed and the path is invariable
Clock synchronization of two measurement points is necessary
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Issues of communication qualities in bullet trains
1. The mobile station (MS) keep moving the entire time and
the communication channel characteristics differ according to
the geographical location of the MS.
•
we need to define the invariant communication qualities of this
environment and find a method for the measure of communication
performance.
2. In order to get the raw packet transmission characteristics
of 3G wireless IP networks, we need to avoid the influence of
possible packet buffers and transport layer protocols like WTCP.
•
•
We can only observe the communication performance over IP layer.
We avoid measuring the network performance with tools using TCP.
3. The one-way measurement need to synchronize the clock of
the two measurement points.
•
There are many tunnels along the route, so it is very difficult to realize
the clock synchronization by using GPS.
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Proposed measurement
Define Route Characteristics in Bullet
Trains as a set of the following
measurements
RPB = {< Delayi, Jitteri, Packet_Lossi, Availabilityi>|i ∈ Locations}
Locations are sampled in a specified timeinterval between the start station and the
terminal station.
Each measurement varies geographically.
We want to get statistical values from RPB
For #1 issue
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Proposed measurement
A proposed measurement from the view of
users
Traditional two-way measurement (RTT)
For #3 issue
ICMP-echo packets in a specified time-interval
The size of probe packet is 84 bytes.
The measurement interval is set to 1 second
Measure from the starting station to the terminal
station
For #2 issue
Two buffer model-based QoS estimation
method is used to measure the raw packet
For #2 issue
transmission characteristics
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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How to measure:
Network configurations of our experiment
Echo CE
Probing CE
IP Address given by au
ACK Packet
Probe Packet
U. of Tokyo Network
1xEV-DO
1xEV-DO
PDSN
The Internet
IP Network of au
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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What to Measure:
The data of our experiment
We measure following data at each
location segment i
RTT (Delayi, Jitteri)
Packet Loss Ratio (Packet_Lossi )
Probing CE Status (PCE_Statusi )
Experiment Target Line
Tokaido Shinkansen (Tokyo－Shin Osaka)「
Nozomi」
No throughput measurement at this time
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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RTT data
RTT (ms)
Tokyo-Shin Shin OsakaOsaka
Tokyo
Static
Min
140
132
131
Max
26199
24503
948
Average
(mean)
661
575
189
Median
400
404
108
1402
1088
42.6
8.5%
7.9%
0%
Standard
deviation
Packet Loss
Ratio
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Cumulative distribution of RTT
Tokyo-Shin Osaka
Shin Osaka-Tokyo
static
Probability
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
100
1000
10000
100000
RTT(ms)
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Cumulative distribution of packet loss
length for Tokyo-Shin Osaka
Probability
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
10
20
30
40
50
60
Packet Loss Length (sec)
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Tokyo-Shin Osaka RTT and Packet Loss
packet loss
RTT
in-tunnel
packet loss
3000 0
RTT(ms)
2500 0
2000 0
1500 0
1000 0
5000
0
0
Shiyokohama
Tokyo
(1084~1168)
(0)
Shinagawa
(365~443)
2000
4000
6000
Nagoya
(6135~6250)
8000
Kyoto
Shiosaka
(8416~8525) (9322)
1000 0
Elapsed time(s)
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Model of wireless communication
environment
Buffer5
Echo CE
Echo CE
Buffer21
Buffer2
Buffer2
Buffer4
Wired Network
Wired Network
Buffer22
CDMA2000 1xEV-DO
Buffer1
Probing CE
CDMA2000 1xEV-DO
Buffer3
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
Buffer1
Probing CE
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How to eliminate the buffer function
from the network
The original TCP specification had TCP update a
smoothed RTT estimator (called R) using the lowpass filter:
R ←− αR + (1 − α)M, α=0.9.
RFC793 recommended the retransmission
timeout value (RTO) be set to as follow:
RTO = Rβ, β=2.
From the point of transport layer protocols, a
large delay is logically considered to be a link
down
We consider that the packet whose RTT is larger than
the 2 times of median of RTT is influenced by the
buffer1 for the link-down period.
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Model of CDMA2000 1xEV-DO
communication environment
Echo CE
Echo CE
ARQ
Buffer
Buffer2
Wired Network
Wired Network
CDMA2000 1xEV-DO
CDMA2000 1xEV-DO
ARQ Buffer
ARQ Buffer
Buffer1
Buffer
ARQ Buffer
Probing CE
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
Probing CE
Buffer
16
Tokyo-Shin Osaka RTT and Packet Loss
(No link-down backup function)
packet loss
RTT
in-tunnel
packet loss
1000
RTT(ms)
800
600
400
200
0
0
Tokyo
Shiyokohama
(1084~1168)
(0)
Shinagawa
(365~443)
2000
4000
6000
Nagoya
(6135~6250)
8000
Kyoto
Shiosaka
(8416~8525) (9322)
10000
Elapsed time(s)
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
17
Cumulative distribution of packet loss length for
Tokyo-Shin Osaka
(No link-down backup function)
Probability
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
10
20
30
40
50
60
70
Packet Loss Length (sec)
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
18
Conclusions and future works
Conclusions
The route characteristics are introduced in QoS metrics for
communication qualities in bullet trains.
Traditional two-way ICMP-echo measurement in a specified
interval can be used to measure them.
A two buffer model-based QoS estimation method is
proposed to eliminate the influence by a large buffer in NIC
of PC.
The raw packet transmission characteristics of CDMA2000
1xEV-DO using the estimation method are gotten.
Future works
The throughput will be statistically estimated by packet-pair
probing. (Preliminary results were got from packets in delay
spikes.)
Using these parameters, make a model of high speed mobile
communication environment on the simulator.
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
19
Thank you for your attention!
Geneva, 12-13 May 2008
3GPP2 Mobile IP
Modified from 3GPP2, “cdma2000 Wireless IP Network Standard: Introduction,” X.S0011-001-D, http://www.3gpp2. org/Public_html/specs/X.S0011-001-D_v1.0_060301.pdf,
Feb.2006.
BS
BSC
BS
BSC
Home Access
Provider Network
HAb
PCF
RADIUSb
PCF PDSNb
HLR
BS
BTS BSC
MS: Mobile Station
RAN: Radio Access Network
BS: Base Station
BTS: Base Transceiver Station
BSC: Base Station Controller
PCF: Packet Control Function
PDSN: Packet Data Serving Node
RADIUS: Remote Authentication Dial-In User Service
FA: Foreign Agent
HA: Home Agent
MSC:Mobile Switching Center
HLR:Home Location Register
SS7 Network
A1
PCF
MSC
PDSNa
IP
Network
BS
BSCa
PCFa
MS
cdma2000 RAN
RADIUSa
Access Provider
Network
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
RADIUSc
HAc
Home IP Network (Private)
CN
21
(a) CDMA2000 1xEV-DO Protocol Reference Model for
MIP4 Control and IKE
MIP4
MIP4 IKE
IKE MIP4
UDP
UDP
UDP
IP
IP/IPsec
IP/IPsec
PPP
cdma2000
Air Interface
MS
PPP
cdma2000
Air Interface
A-9
A-9
A-11
A-11
PL
PL
PL
PL
BTS,BSC
PCF
L2
L2
PL
PL
PDSN/FA
HA
Modified from 3GPP2, “cdma2000 Wireless IP Network Standard: Introduction,” X.S0011-001-D, http://www.3gpp2. org/Public_html/specs/X.S0011-001-D_v1.0_060301.pdf,
Feb.2006.
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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(b) CDMA2000 1xEV-DO Protocol Reference Model for
MIP4 User Data
IP
IP
PPP
cdma2000
Air Interface
MS
IP
IP
IP/IPsec
IP/IPsec
L2
L2
L2
L2
PL
PL
PL
PL
PPP
cdma2000
Air Interface
A-8
A-8 A-10 A-10
PL
PL
BTS,BSC
PL
PCF
PL
PDSN/FA
HA
CN
Modified from 3GPP2, “cdma2000 Wireless IP Network Standard: Introduction,” X.S0011-001-D, http://www.3gpp2. org/Public_html/specs/X.S0011-001-D_v1.0_060301.pdf,
Feb.2006.
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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A-8/A-9 and A-10/A-11
PPP
Signalings
PPP
Signalings
GRE
UDP
GRE
UDP
IP
IP
IP
IP
L2
L2
L2
L2
PL
PL
PL
PL
(c1) A-8
(c2) A-9
(c) BSC-PCF Interface
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
(d1) A-10
(d2) A-11
(d) PCF-PDSN Interface
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