Trial on the Efficient Use of Trunk Communcation Lines for VLBI

in Japan

Noriyuki Kawaguchi

NATIONAL Astronomial Observatory,Japan

eVLBI Workshop2008.6.17@Shanghai Observatory

Contents

(1) 10GbE connection with variable bit rate Kashima 34m and Koganei 11m

(2) L1 on-demand connection Yamaguchi 32m and Tsukuba 32m

(3) Link Aggregation of multiple GbE links Tomakomai 11m access link

Test Fields in Japan

Tomakomai11m

Hokkaido UniversitySapporo

Kashima34m

Koganei11m

L1 on-demand

Yamaguchi32m Tsukuba

32m

GbE Aggregation

10GbE connection

10GbE Connection

D Port ＃１

C Port ＃１

D Port ＃ 2

C Port ＃ 2

D Port ＃ 3

C Port ＃ 3

D Port ＃ 4

C Port ＃ 4

VSI(DIM,2048Mbps)ADS-1000

VDC-100F VSI(DOM,2048Mbps)

VSI(DIM,2048Mbps)ADS-1000

VDC-100F VSI(DOM,2048Mbps)

VSI(DIM,2048Mbps)ADS-1000

VDC-100F VSI(DOM,2048Mbps)

VSI(DIM,2048Mbps)ADS-1000

VDC-100F VSI(DOM,2048Mbps)

Cont. CPU

ＧｂＥ

１０ＧｂＥ１０Ｇ－ＢＡＳＥ－ＬＲ１．３ μm

１０ＧｂＥUnit

ＧｂＥ

Network CPU

ＳＩＮＥＴ３

（ Comm. & Cont.）

（ Local Control）

ＣＴＬＰ（ Cont. Port）

ＣＨＬＰ（ Comm. POrt ）

2.048 Gbps x 4 I/O ports 10GbE Port

Photo

10GbEUnit

From Kashima

FromKoganei11m

2GHz A/D

Real time Correlator

10 GbE Analyzer

Bit Rate Control in congestion

Bit RateDown to2Gbps

Bit RateDown to1Gbps

Bit RateDown to0.5Gbps

Time Code Not detected

Time Code Partially detected

Time Code completely detected.Possible to startcorrelation

Packet Arrival Time Records

No Congestion Under heavy congestion

Many packets are stockedin memory and suddenly released in very short time.

New function to pick up the suddenly released packetsare now considered.

Data Flow Monitoring

L1 on-demand connection

Efficient Use of limited Resource

• We can enjoy long time and wide bandwidth on Saturday and Sunday!

L1 on-demand connection

(1)Reservation (30minutes before observation)1) Request to the connection time2) Request to the bandwidth3) Negotiation for time and bandwidth4) Report for the time and bandwidth granted

(2)Telescope Operation(3)Real time Fringe Monitoring

First Success in real time observation on L1 on-demand connection

June 12,2008

Yamaguchi 32mTsukuba 32m

X-band2Gbps

Link Aggregation Technique

Binding cheap low-bit-rate links

And

Getting a extremely high bit rate

Link Aggregation of multiple GbEs

FoundryMLX-4

FoundryMLX-4

ADS-1000

BW=512MHｚ（ 512-1024MHz）

VOA-200 SINET3A/D converterof 2.048-Gbpssampling

10GbEUnit Hope to carry 2Gbps

payload through threeGbE connections

ToMitaka, Tokyo

Hokkaido Universityin Sapporo

11m Telescopein Tomakomai

GbE x 3

Connections with low bit ratelinks in cheap cost

The link aggregation test will start in this summer.

Space Light Path

光空間伝送

Town, City

Observatory

Trunk CommunicationLine

Laser Beam Tracking Mirror developed10-Gbps, 10-km connection is a target.

Compact Opt TX/RX system

Conclusions

• Efficient Use of Communication Line– shared use of 10GbE line

• successfully demonstrated in the test between Kashima-Koganei

– L1 on-demand connection• successfully performed in the first test between Ymaguchi an

d Tsukuba

– Link Aggregation• to be achieved in 2008

– Space Light Path Connection• To be tested in Usuda 64m site