e-VLBI Developments at JIVE

1. e-VLBI Developments at JIVE Arpad Szomoru

2. Outline • Current status, recent results • Network upgrades • EXPReS: first results • Connectivity improvements • The future..

3. 1 Gbps 10 Gbps 155 Mbps 2.5 Gbps

4. Recent developments • Regular science/test sessions throughout the year • First open calls for e-VLBI science proposals • First science run completely lost, but, first ever real-time fringes to Mc (128 Mbps) • Second and third science runs: many hours of smooth sailing at 128 Mbps

5. Current status • Technicaltests: • 6-station fringes at 256 Mbps • first European 512 Mbps fringes (Jb and Wb, May 18) • 3-station 512 Mbps fringes (Cm, Wb, On, August 21) • first fringes using new 5 GHz receiver at Mc • Current connectivity: • Ar: 64 Mbps in the past, but <32 Mbps this year • European telescopes: 128 Mbps always, 256 Mbps often, 512 Mbps to Wb, Jb and On

7. Tr connectivity bottleneck - solved • Black Diamond 6808 switches: • New interfaces (10GE) system in old architecture (1GE) • Originally 8x1GE interface per card • 10GE NIC served by 8 x 1GE queues • Queuing regime – RR (packet based) and flow-based • Flow based: • Max. flow capacity – 1Gbit/s – backround traffic. • There is no known reordering workaround to solve this problem.

8. e-VLBI to South America? SMART-1 SMART-1 factsheet Testing solar-electric propulsion and other deep-space technologiesName SMART stands for Small Missions for Advanced Research in Technology.  Description SMART-1 is the first of ESA’s Small Missions for Advanced Research in Technology. It travelled to the Moon using solar-electric propulsion and carrying a battery of miniaturised instruments. As well as testing new technology, SMART-1 is making the first comprehensive inventory of key chemical elements in the lunar surface. It is also investigating the theory that the Moon was formed following the violent collision of a smaller planet with Earth, four and a half thousand million years ago.Launched 27 September 2003 Status Arrived in lunar orbit, 15 November 2004. Conducting lunar orbit science operations. Notes SMART-1 is the first European spacecraft to travel to and orbit around the Moon. This is only the second time that ion propulsion has been used as a mission's primary propulsion system (the first was NASA's Deep Space 1 probe launched in October 1998). SMART-1 is looking for water (in the form of ice) on the Moon. To save precious xenon fuel, SMART-1 uses 'celestial mechanics', that is, techniques such as making use of 'lunar resonances' and fly-bys.

9. e-VLBI to Sourth America (2)

10. And other continents.. Australia: • Telescopes connected • PCEVN-Mk5 interface needed China: • Shanghai Observatory connected at 2.5Gbps • Connection via TEIN (622Mbps), ORIENT? Issues with CERNET, CSTNet • Direct lightpath Hong Kong-Netherlight?

11. Hybrid networks in the Netherlands..

12. Switch from Cisco to Nortel/Avici equipment has been completed: for now, 7 * 1 Gbps, ultimately 16 * 1 Gbps.

13. ..and across Europe: GÉANT2 network upgrade Outline

14. EXPReS: now what? SA1: new hires at JIVE (two software engineers, one network engineer, one e-VLBI postdoc) Inclusion of e-MERLIN telescopes in e-EVN Operational improvements (deliverable driven): • Robustness • Reliability • Speed • Ease of operation • Station feedback And still, pushing data rates, protocols, UDP, Circuit TCP? Get rid of fairness… Better usage of available bandwidth.

15. e-VLBI control interface

16. Interface to station Mk5s

17. Runtime control

18. Integrating fringe display

19. Data status monitor

20. Streamlining of post processing

21. Web-based Post-processing

22. Ongoing New control computers (Solaris AMD servers) • Cut down on (re-)start time • Powerful code development platform • Tightening up of existing code • Operational within next few weeks Other hardware upgrades: • SX optics (fibres + NICs), managed switches at JIVE and SARA • Mark5A→B: motherboards, memory, power supplies, serial links, CIBs

23. And coming.. FABRIC: • Distributed software correlation • High bandwidth data transport (On part of e-MERLIN @ 4Gbps) • Two new hires at JIVE SCARIe: • Collaboration with SARA and UvA • Distributed software correlation using Dutch grid • Lambda switching, dynamical allocation of lightpaths • JIVE postdoc hired, still looking for UvA postdoc

24. user correlator parameters FABRIC components GRID resources data observing schedule in VEX format earth orientation parameters field system controls antenna and acquisition resource allocation and routing correlator control including model calculation DBBC VSI output data FABRIC = The GRID VSIe?? on?? PC-EVN #2

25. Martin Swany

27. 2 Heavy duty gamer PCs • Tyan Thunder K8WE Motherboards • Dual AMD Opteron 2.4GHz processors • 4GB RAM • 2 1Gb PCI-Expres Nics • First one at Torun, back-to-back to Mark5 • Second one located at Poznan Supercomputing Centre

28. Protocols (1) Mix of High Speed and Westwood TCP (Sansa)

29. Protocols (2) Circuit TCP (Mudambi, Zheng and Veeraraghavan) Meant for Dedicated End-to-End Circuits, fixed congestion window No slow start, no backoff: finally, a TCP rude enough for e-VLBI?

30. Protocols (3) Home-grown version of CTCP using pluggable TCP congestion avoidance algorithms in newer Linux kernels (Mark Kettenis) Rock-steady 560 Mbps transfer using iperf from Mc to JIVE Serious problem with new version of Mk5A software under newer kernels

31. Aim: 16 * 1 Gbps production e-EVN network IP: not possible/affordable 10 Gbps lightpath across Europe: currently ~20k€/year Lightpaths across GÉANT terminating at JIVE If possible, all the way from telescopes. If not, overprovisioned IP connections from telescopes to GÉANT, lightpaths from there on. Guaranteed bandwidth, possibility to use ethernet frames, no more need to worry about congestion.. A true connected-element interferometer e-EVN: the future

32. External LPs GEs, STM-64 direct Mk5 OME network OME network N GE Switch Switch Mk5 N GE Mk5 Dynamic capabilities through DRAC 10 G IP Proposed connection Surfnet-JIVE