SA1: technical progress

1. SA1: technical progress Arpad Szomoru JIVE

2. e-VLBI: operational improvements • Overall improvement in first 16 months: • Robustness • Reliability • Speed • Ease of operation • Station feedback • Minimizing data loss by careful scheduling • Increase of production data rate from 128 Mbps to 256 Mbps • 6-station fringes at 512 mbps • Inclusion of Metsähovi and Medicina telescopes Arpad Szomoru, eVSAG, Gothenburg

3. e-VLBI: data rate improvements Arpad Szomoru, eVSAG, Gothenburg

4. Operational e-VLBI: latest results Arpad Szomoru, eVSAG, Gothenburg

5. The EVN MarkIV correlator Custom-made hardware, ~500000 lines of C++ code Designed and built on tape technology, only recently adapted for disk-based recording Arpad Szomoru, eVSAG, Gothenburg

6. Work packages • Standard e-VLBI correlator mode: • Wall-clock time vs ROT • Centralized control • Rapid response/ToO functionality: • Real-time monitoring/feedback/analysis • On-the-fly adjustment of observational/correlator parameters • Improved amplitude calibration • Data transport issues • Lightpaths: guaranteed (high) bandwidth • Transport protocols (modified TCP, UDP-based, VSI-e…) • Hardware issues • New control computers (reliability, speed) • Replacement of SUs (cause of much misery) • Networking hardware (router, interfaces) Arpad Szomoru, eVSAG, Gothenburg

7. e-VLBI correlator mode: control interfaces Arpad Szomoru, eVSAG, Gothenburg

8. Monitoring tools: Integrating fringe display Arpad Szomoru, eVSAG, Gothenburg

9. Monitoring tools: Data status monitor Arpad Szomoru, eVSAG, Gothenburg

10. Monitoring tools: Data status monitor Arpad Szomoru, eVSAG, Gothenburg

11. Rapid adjustment of correlator params: vex editor Arpad Szomoru, eVSAG, Gothenburg

12. (near) Real-time analysis: streamlining of post processing Arpad Szomoru, eVSAG, Gothenburg

13. Web-based Post-processing Arpad Szomoru, eVSAG, Gothenburg

14. Hardware New control computers • Solaris AMD servers, redundant power supplies • Interchangeable for maximum reliability • Cut down dramatically on (re-)start time • Removal of single points of failure Mark5 upgrade • Original Mark5s woefully under-powered (Pentium PIII…) New dual processor motherboards, memory, power supplies • Mark5A→B: new streamstor cards, new serial links (optical and coax), Correlator Interface Boards • Elimination of Station Units, VSI compliance Arpad Szomoru, eVSAG, Gothenburg

15. Upgrade of network at JIVE Arpad Szomoru, eVSAG, Gothenburg

16. Arpad Szomoru, eVSAG, Gothenburg

17. SA1: the next 18 months All personnel in place, at JIVE and JBO Main focus: • Adaptive scheduling • Increasing the operational data rate • Improving flexibility and robustness of correlation • New telescopes • Inclusion of eMERLIN telescopes • Re-assessment/refinement of deliverables Arpad Szomoru, eVSAG, Gothenburg

18. Specific tasks Crucial: • fast/adaptive (re-)scheduling • Transform EVN into a truly flexible instrument • Reaction time of hours • Remote control of widely different telescope control systems • Safeguard local operational constraints • hard/software upgrade • Phase out aging Station Units, cause of much misery • Involves large software effort • VSI compliance Arpad Szomoru, eVSAG, Gothenburg

19. Fine-tuning of deliverables • Use of WSRT synthesis data for e-VLBI calibration (absolute flux calibration, polarization calibration, source selection) • Space craft tracking correlator mode • On-the-fly fringe fitting • Real-time download and extraction of station information • Automated correlator diagnostics • Removing/adding stations from the correlation process on the fly • Investigating a 1024M sub-array Arpad Szomoru, eVSAG, Gothenburg

20. Connectivity improvements: • Use of new/modified transport protocols, lightpaths across Europe • Increase granularity of data streams to optimize utilization of available bandwidth • Increase of sensitivity and resolution through addition of telescopes: Effelsberg, Yebes, Shanghai • Improving global connectivity: South-America, Puerto Rico, China, Australia Arpad Szomoru, eVSAG, Gothenburg

21. Global connectivity: • Arecibo: 64 Mbps real-time operations in the past, currently < 32 Mbps. New submarine cable facilities in near future… • Australia: 4 LBA telescopes connected at 1 Gbps. Lightpath to Europe via Canada will be available next Monday. Issues with format conversion (VSI-Mark5B-Mark5A+), command interfaces, long haul transport • First tests (not via lightpath): interface seems to work, format conversion unclear as yet, but yellow leds at 64 Mbps (from three telescopes) Arpad Szomoru, eVSAG, Gothenburg

22. ORIENT: 2.5 G TEIN2: 622 M 1G 100M 155 M 2.5G 34 M 2.5G 50 M 1G 622 M 1G HKOEP e-VLBI to China SURFnet Arpad Szomoru, eVSAG, Gothenburg

23. e-VLBI to China (2) • Lightpath Sheshan (near Shanghai) – JIVE in place (via HongKong, Chicago). RTT 360 ms. • Test results (iperf) • 930 Mbps Seshan – Hong Kong (!!) • 400 Mbps Hong Kong – JIVE • ~100 Mbps Seshan – JIVE • But… issues with security machines, shared bandwidth, reservation of timeslots needed • New lightpath via Siberia available since last Monday Arpad Szomoru, eVSAG, Gothenburg

24. e-VLBI to China (3) • First operational results: impossible to reach 32 Mbps • Old Linux kernel, TCP Reno, lossy connection, very long RTT Arpad Szomoru, eVSAG, Gothenburg

25. Next big issue • Long haul transport *not* via lightpath: need either modified TCP or UDP based protocol • New streamstor libraries will be available real soon now: disable congestion control • Mark5A code has been fiddled to work with plain UDP again • Collaboration with Manchester to fold VLBI_UDP into Mark5A code is ongoing • Will have to work before APAN meeting demo… Arpad Szomoru, eVSAG, Gothenburg