the research network serving for evlbi application——cstnet

7th International eVLBI Workshop

The research network serving for eVLBI application——CSTnet

Jun.2008Xiaodan Zhang


Outline

• Introduction on CSTnet

• Testing and demo for eVLBI

• Challenge and thought


Development and resource


Export Resource


Incoming resources


Gloriad DV-NOC• http://dev.gloriad.org:8080/viz/dvnoc/dvno

c.html

http://dev.gloriad.org:8080/viz/dvnoc/dvnoc.html

http://dev.gloriad.org:8080/viz/dvnoc/dvnoc.html


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)


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


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


Light path for eVLBI


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


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


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


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%


Real-time Test Result on Jun 5


Factors affecting the transmission rate

• Network environment

• Terminal Sever

• System Kernel

• Network Transfer Protocol


Network Environment

Hong Kong

Seattle

Mopra

Los Angeles

Honolulu

Chicago

Singapore


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%


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


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


Challenges and Thought


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


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.


How to do it ? (2)

• Distributed framework distributed correlation

• Parallel recording on hardware

• Network traffic control

• Dynamic Optical Networking

• And so on


Thanks!

the research network serving for evlbi application——cstnet

Documents

scientific data

technology networks

abundant resources

disease control

state land

krlight path

cnus gloriadmay

cneu evlbiaug