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7th International eVLBI Workshop
The research network serving for eVLBI application——CSTnet
Jun.2008Xiaodan Zhang
7th International eVLBI Workshop
Outline
• Introduction on CSTnet
• Testing and demo for eVLBI
• Challenge and thought
7th International eVLBI Workshop
Development and resource
7th International eVLBI Workshop
Export Resource
7th International eVLBI Workshop
Incoming resources
7th International eVLBI Workshop
7th International eVLBI Workshop
Gloriad DV-NOC• http://dev.gloriad.org:8080/viz/dvnoc/dvno
c.html
7th International eVLBI Workshop
Background of BJLight It’s built base on the project of CNGI Having optical fiber connections with nearl
y 30 national science and technology networks cover many scientific areas
• A exchange center on scientific data in China
• Provide a platform and be a Promotion to national and international scientific cooperation and Application
• Expansibility: abundant resources, dark fibers in Beijing(N*10G)
7th International eVLBI Workshop
Resources on Many Scientific Areas
• China Earthquake Data Center• China meteorological Data Sharing
Network • China topography Science Data Sharing
Network • China Forestry Data Sharing Network• Data-Sharing Network of Earth System
Science• Network of Science on State Land and
Resource• Sustainable Development Information
Center• Geognosy and Mineral Resource Data
Sharing Network• Chinese Medical and Health Network• China Communications Science Network• Basic Science Date Center• Advanced Manufacturing and Automation
Network• China Hydrology Science Network• Chinese Academy of Agriculture Sciences
Network
• China environmental Science Network• Chinese Area Integration science and technolog
y Data Sharing Network• National Science and technology Library Networ
k • Research of Petroleum Processing Network• National Center for Nanoscience and Technolog
y Network• National Metrology Science Network• China Academy of Railway Sciences Network• China Water Resources and hydropower Resear
ch Network• Genomics Science Network• China Academy of Telecommunication Technolo
gy Network• Network of Chinese Center for Disease Control
and Prevention• Chinese Academy of Social Sciences Network• Architectural Design Science Network
7th International eVLBI Workshop
Structure of BJLight
BJLight
China meteorological Data Sharing Network
China topography Science Data Sharing Network
Advanced Manufacturing and
Automation Network
Basic Science Date Center
Chinese Academy of Agriculture Sciences
Network
Sustainable Development Information Center
Geognosy and Mineral Resource Data Sharing Network
Chinese Medical and Health Network
China Communications Science Network
China Hydrology Science Network
Network of Science on State Land and Resource
Data-Sharing Network of Earth System Science
China Forestry Data Sharing Network
China Earthquake Data Center
China environmental Science Network
China Academy of Telecommunication Technology Network
Research of Petroleum Processing Network
China Academy of Railway Sciences Network
National Center for Nanoscience and Technology Network
National Metrology Science Network
Chinese Area Integration science and technology Data Sharing Network
Genomics Science Network
China Water Resources and hydropower Research Network
National Science and technology Library
Network
Chinese Academy of Social Sciences Network
Network of Chinese Center for Disease Control and Prevention
Architectural Design Science Network
CSTNET
HKOEP
GLORIAD-RU
GLORIAD-US
GLORIAD-KR
7th International eVLBI Workshop
7th International eVLBI Workshop
7th International eVLBI Workshop
Light path for eVLBI
7th International eVLBI Workshop
Light path status
2.5G10G2.5G
HK Seattle Chicago
Gloriad-US
2.5G 10G2.5G 10G
Beijing HKSeattle
L.A. AU
2.5G 10G2.5G
HKSeattle Chicago Netherlands
CN-AU eVLBI
Jun.2008
CN-EU eVLBI
Aug.2007
CN-US Gloriad
May.2006
7th International eVLBI Workshop
Encapsulation problem and solution
BeijingSeattle
HK L.A. AU
Parkes,Mopra
2.5G10G2.5G 10G
Sheshan, SH
Can’t support
VCAT
Drop in HK by VC4-4C
16VC4
VCAT
VC4-4C
4*vc4 VC4-4C
7th International eVLBI Workshop
End to End Testing
• Severs
software
Sever Name Facility Type System Kernel
ShangHai sever Mark5 red hat 2.4.20-31.9smp
BeiJing sever IBM x3650 Debian 2.6.18-4-686
Hong Kong sever Dell 2850 Debian 2.6.18-4-686
Iperf version 2.0.2
Parameter : TCP windows size: 16M UDP bandwith:512M
7th International eVLBI Workshop
Test result for Sheshan and Parkes
BeiJing
Hong Kong
Seattle
Parkes
Los Angles
Honolulu
ShangHai
SHBJL3 Network
TCP : 930Mbps
LP : 0%
BJ HK622M Light pat
hTCP : 490Mbp
sLP : 0%
HKAU622M Light pat
hTCP : 495Mbp
sLP : 0%
7th International eVLBI Workshop
Real-time Test Result on Jun 5
7th International eVLBI Workshop
Factors affecting the transmission rate
• Network environment
• Terminal Sever
• System Kernel
• Network Transfer Protocol
7th International eVLBI Workshop
Network Environment
Hong Kong
Seattle
Mopra
Los Angeles
Honolulu
Chicago
Singapore
7th International eVLBI Workshop
Result
Network Environment Protocol speed Jitter Loss packet
L3 Network
TCP 295 Mbits/sec - -
UDP 509 Mbits/sec 0.025 ms 1.5%
622MLight path
TCP 495 Mbits/sec - -
UDP 535 Mbits/sec 0.024 ms 0%
7th International eVLBI Workshop
Terminal Cases
Sever Name Facility Type Cpu memory Ethernet card
Beijing Sever 1 Dell Intel 3.2GHZ 2GB
Beijing Sever 2 IBM x3650 Double Intel 3.2GHZ 4GB Intel Integrated Card
Hong Kong sever
Dell 2850 Double Intel 3.2GHZ 4GB Intel (R) Pro/1000 MF
Sever Name Facility Type System Kernel
Shanghai sever Mark5 Debian 2.4.27
Debian 2.6.18-4-686
BeiJing sever IBM x3650 Debian 2.6.18-4-686
7th International eVLBI Workshop
Network Transfer Protocol and other factors
TCP
Reliable
Not so good bandwidth
Fair
Poor for long delay
UDP
No ACK
Stable and high bandwidth
Little data loss but OK
Outstanding for long delay
7th International eVLBI Workshop
Challenges and Thought
7th International eVLBI Workshop
what we need?
• Realtime
• Long baseline between many telescopes 1000km ~ 20000km
• No data loss, Some losses are tolerable
• High speeds 128Mbps256Mbps 512Mbps 1024Mbps, more is better
• Smooth, little jitter
7th International eVLBI Workshop
How to do it ? (1)• Transmit protocols UDP maybe is a logical solution
Many researcher focus on it and make it applicable to all VLBI hardware and software Add some congestion control capabilities
• Traditional multiple routes is hard to control, Light paths more better. Light path is still have problem,
If point to point light path down….what you can do? Hybrid network Can we do some improves on our current network, Efficiency is important, can’t expand it blindly.
7th International eVLBI Workshop
How to do it ? (2)
• Distributed framework distributed correlation
• Parallel recording on hardware
• Network traffic control
• Dynamic Optical Networking
• And so on
7th International eVLBI Workshop
Thanks!