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
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

3. e-VLBI: data rate improvements
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

4. Operational e-VLBI: latest results
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

5. The EVN MarkIV correlator
Custom-made hardware, ~ lines of C++ code
Designed and built on tape technology, only recently adapted for disk-based recording
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

6. Arpad Szomoru, eVSAG, Gothenburg
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)
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

7. e-VLBI correlator mode: control interfaces
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

8. Monitoring tools: Integrating fringe display
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

9. Monitoring tools: Data status monitor
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

10. Monitoring tools: Data status monitor
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

11. Rapid adjustment of correlator params: vex editor
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

12. (near) Real-time analysis: streamlining of post processing
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

13. Web-based Post-processing
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

14. Arpad Szomoru, eVSAG, Gothenburg
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
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

15. Arpad Szomoru, eVSAG, Gothenburg
Upgrade of network at JIVE
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

16. Arpad Szomoru, eVSAG, Gothenburg
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

17. Arpad Szomoru, eVSAG, Gothenburg
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
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

18. Arpad Szomoru, eVSAG, Gothenburg
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
2007 June 28
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
2007 June 28
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
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

21. Arpad Szomoru, eVSAG, Gothenburg
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)
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

22. Arpad Szomoru, eVSAG, Gothenburg
e-VLBI to China
1 G
2.5 G
155 M
100 M
50 M
34 M
HKOEP
622 M
ORIENT: 2.5 G
TEIN2: 622 M
SURFnet
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

23. Arpad Szomoru, eVSAG, Gothenburg
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
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

24. Arpad Szomoru, eVSAG, Gothenburg
e-VLBI to China (3)
First operational results: impossible to reach 32 Mbps
Old Linux kernel, TCP Reno, lossy connection, very long RTT
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg

25. Arpad Szomoru, eVSAG, Gothenburg
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…
2007 June 28
Arpad Szomoru, eVSAG, Gothenburg