e-vlbi and end-to-end performance masaki hirabaruyasuhiro koyamatetsuro kondo nict koganeinict...
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e-VLBI and End-to-End PerformanceMasaki Hirabaru Yasuhiro Koyama Tetsuro Kondo
NICT Koganei NICT Kashima NICT Kashima
[email protected] [email protected] [email protected]
VLBI (Very Long Baseline Interferometry)
dela
y
radio signal from a star
correlator
A/Dclock
A/D
Internet
clock
ASTRONOMYGEODESY
~Gbps~Gbps
Fringe
•e-VLBI geographically distributed observation, interconnecting radio antennas over the world
Large Bandwidth-Delay Product Network issue
•Gigabit / real-time VLBI multi-gigabit rate sampling
Example: From Tokyo to BostonTCP on a fast long path with a bottleneck
bottleneck
overflowqueue
loss
Tokyosenderrate control
Bostonreceiverloss detection
feedback
It takes 150ms to know the loss (buffer overflow).It keeps overflowing during the period…150ms is very long for the high-speed network.150ms at 1Gbps generates ~19MByte on the wire.
Los Angeles
50ms 50ms
100ms
bw 1G
bw 0.8G
Analyzing Advanced TCP Dynamic Behavior in a Real Network(Example: From Tokyo to Indianapolis at 1G bps with HighSpeed TCP)
The data was obtained during e-VLBI demonstration at Internet2 Member Meeting in October 2003.
ReceiverLinux TCP
SenderLinux 2.4
GbE
RTT 200ms(100ms one-way)
GbE
Only 800 Mbps available
Replaying in a Laboratory-Evaluation of Advanced TCPs-
TCP NewReno (Linux)
HighSpeed TCP (Web100)
Example of Advanced TCPs with different bottleneck queue sizes
BIC TCP queue size 100 packets FAST TCP queue size 100 packets
BIC TCP queue size 1000 packetsFAST TCP queue size 1000 packets
RouterSwitch RouterSwitch
1Gbps
100Mbps1Gbps
1Gbps
a) b)
DeviceQueuing
Delay (µs)Capacity (Mbps)
Estimated Queue Size
(1500B)
Switch A 6161 100* 50
Switch B 22168 100* 180
Switch C 20847 100* 169
Switch D 738 1000 60
Switch E 3662 1000 298
Router F 148463 1000 12081
Router G 188627 1000 15350
* set to 100M for measurement
Measuring Bottleneck Queue Sizes
Switch/Router Queue Size Measurement Result
Typical Bottleneck Cases
ReceiverSenderCapacity C
packet trainlost packet
measured packet
Queue Size = C x (Delaymax – Delaymin)
KwangjuBusan
2.5G
Fukuoka
Korea
2.5G SONET
KORENTaegu
Daejon
10G
1G (10G)1G
1G
Seoul XP
Genkai XP
Kitakyushu
Kashima
1G (10G)
Fukuoka Japan
250km
1,000km2.5G
JGN II
9,000km
4,000km
Los Angeles
Chicago
Washington DC
MIT Haystack
10G
2.4G
APII/JGNII
Abilene
Koganei
1G(10G)
Indianapolis
100kmbwctl server
Experiment for High-Performance Scientific Data Transfer
10G
Tokyo XP /JGN II I-NOC
*Performance Measurement Point Directoryhttp://e2epi.internet2.edu/pipes/pmp/pmp-dir.html
perf server
e-vlbi server
JGNII
10G
GEANT
SWITCH
7,000km
TransPAC
Pittsburgh
U of Tokyo
A BWCTL account available for CMMincluding Korean researchers
International collaboration to support science applications
VLBI Antenna Locations in North-East Asia
Shintotsukawa 3.8m
Tomakomai 11m, FTTH (100M)70km from Sapporo
Mizusawa 10m 20m118km from Sendai
Tsukuba 32m, OC48/ATMx2 SuperSINET
Kashima 34m, 1Gx2 JGN, OC48/ATM Galaxy
Yamaguchi 32m1G, 75M SINET
Gifu 11m 3m, OC48/ATMx2 SuperSINET
Usuda 64m, OC48/ATM Galaxy
Nanshan (Urumqi) 25m70km from Urumqi
Koganei 34m, 1Gx2 JGN, OC48/ATM Galaxy
Miyun (Beijing) 50m50km from Beijing
2Mbps
2Mbps
Sheshan (Shanghai) 25m30km from Shanghai
Observatory is on CSTNET at 100M Jeju 20m
Tamna U
Seoul 20mYonsei U
Ulsan 20mU Ulsan
Daejon 14mTaeduk
Ishigaki 20m
Ogasawara 20mChichijima 10m
Iriki 20mKagoshima 6mAira 10m
Legendconnectednot yet connectedantenna under construction
Summary and Future Work
•High-performance scientific data transfer faces on network issues we need to work out.•Big science applications like e-VLBI and High-Energy Physics need cooperation with network researchers.•Deployment of performance measurement Infrastructure is on-going on world-wide basis.•Lessens are shared with CHEP and KAIST experiments over APII and TransPAC as well as CMM (Common Measurement Machines).
ENP2611Network
Processor Emulator
APII Workshop 2004 October 28-29, 2004
Appendix - VLBI System Transitions
K5 Data AcquisitionTerminal
1st Generation
2nd Generation
1983~Open-Reel TapeHardware Correlator
1990~Cassette TapeHardware Correlatore-VLBI over ATM
3rd Generation
2002~PC-based SystemHard-disk StorageSoftware Correlatore-VLBI over Internet
K3 Correlator (Center)K3 Recorder (Right)
K4 Terminal
K4 Correlator
64Mbps
256Mbps
1 ～ 2Gbps
Nobeyama 45mOC48/ATM Galaxy