Trial on the Efficient Use of Trunk Communcation Lines for VLBI in Japan

1. eVLBI Workshop 2008.6.17@Shanghai Observatory Trial on the Efficient Use of Trunk Communcation Lines for VLBI in Japan Noriyuki Kawaguchi NATIONAL Astronomial Observatory,Japan

2. Contents • 10GbE connection with variable bit rate • Kashima 34m and Koganei 11m • L1 on-demand connection • Yamaguchi 32m and Tsukuba 32m • Link Aggregation of multiple GbE links • Tomakomai 11m access link

3. Test Fields in Japan Hokkaido University Sapporo GbE Aggregation Tomakomai 11m 10GbE connection Kashima 34m L1 on-demand Koganei 11m Yamaguchi 32m Tsukuba 32m

4. １０ＧｂＥ Unit ADS-1000 VSI(DIM,2048Mbps) D Port ＃１ D Port ＃2 D Port ＃3 D Port ＃4 VSI(DOM,2048Mbps) VDC-100F C Port ＃4 C Port ＃3 C Port ＃１ C Port ＃2 １０ＧｂＥ ＳＩＮＥＴ３ ADS-1000 VSI(DIM,2048Mbps) １０Ｇ－ＢＡＳＥ－ＬＲ １．３μm VSI(DOM,2048Mbps) VDC-100F ＧｂＥ ADS-1000 ＣＨＬＰ （Comm. POrt） VSI(DIM,2048Mbps) VSI(DOM,2048Mbps) VDC-100F Network CPU ADS-1000 VSI(DIM,2048Mbps) （Comm. & Cont.） VSI(DOM,2048Mbps) VDC-100F ＧｂＥ Cont. CPU ＣＴＬＰ （Cont. Port） （Local Control） 10GbE Connection 2.048 Gbps x 4 I/O ports 10GbE Port

5. Photo Real time Correlator 10GbE Unit From Kashima 2GHz A/D From Koganei 11m 10 GbE Analyzer

6. Bit Rate Control in congestion Bit Rate Down to 2Gbps Time Code Not detected Time Code Partially detected Bit Rate Down to 1Gbps Time Code completely detected. Possible to start correlation Bit Rate Down to 0.5Gbps

7. Packet Arrival Time Records No Congestion Under heavy congestion Many packets are stocked in memory and suddenly released in very short time. New function to pick up the suddenly released packets are now considered.

8. Data Flow Monitoring

9. L1 on-demand connection

10. Efficient Use of limited Resource • We can enjoy long time and wide bandwidth on Saturday and Sunday!

11. L1 on-demand connection • Reservation (30minutes before observation) • Request to the connection time • Request to the bandwidth • Negotiation for time and bandwidth • Report for the time and bandwidth granted • Telescope Operation • Real time Fringe Monitoring

12. First Success in real time observation on L1 on-demand connection June 12, 2008 Yamaguchi 32m Tsukuba 32m X-band 2Gbps

13. Link Aggregation Technique Binding cheap low-bit-rate links And Getting a extremely high bit rate

14. Link Aggregation of multiple GbEs Connections with low bit rate links in cheap cost 11m Telescope in Tomakomai Hokkaido University in Sapporo BW=512MHｚ （512-1024MHz） ADS-1000 VOA-200 SINET3 GbE x 3 Foundry MLX-4 To Mitaka, Tokyo Foundry MLX-4 A/D converter of 2.048-Gbps sampling 10GbE Unit Hope to carry 2Gbps payload through three GbE connections The link aggregation test will start in this summer.

15. 光空間伝送 Town, City Observatory Trunk Communication Line Space Light Path Laser Beam Tracking Mirror developed 10-Gbps, 10-km connection is a target.

16. Compact Opt TX/RX system

17. 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 and Tsukuba • Link Aggregation • to be achieved in 2008 • Space Light Path Connection • To be tested in Usuda 64m site