1. e-EVN developments in 2006
Arpad Szomoru

2. Outline The past Current status Expansion of e-EVN
EXPReS: first results
Connectivity improvements
The future

3. e-VLBI Milestones September 2002: 2 X 1 Gbit Ethernet links to JIVE
Demonstrations at igrid2002 and ER2002
UDP data rates over 600 Mbit/s

4. Chalmers University of Technology, Gothenburg
May 2003: First use of FTP for VLBI session fringe checks.
e-VLBI Milestones: 2003
July:10 Gbit access GEANT-Surfnet
6 X 1 Gbit links to JIVE
Onsala Sweden
Chalmers University of Technology, Gothenburg
November 2003: Onsala Space Observatory (Sweden) connected at 1Gb/s.
November 2003: Cambridge – Westerbork fringes detected, only 15 minutes after observations were made.
64Mb/s, with disk buffering at JIVE only.
September: e-VLBI data transfer between Bologna and JIVE – 300Mb/s
October 2003: first light on Westerbork – JIVE 1 Gb/s connection

5. April 2004: Three-telescope, real-time fringes at 64Mb/s (On, Jb, Wb).
First real-time EVN image at 32Mb/s
December : connection of JBO to Manchester at 2 x 1 Gb/s
e-VLBI test with Tr, On and Jb
Jb - Tr fringes at 256Mb/s
March 2004: first real-time fringes Westford-GGAO to Haystack
Intercontinental real-time fringes, Wf -On, 32 Mb/s
September 2004: Four telescope real-time e-VLBI (Ar, Cm, Tr, Wb)
First fringes to Ar at 32 Mb/s
September 2004: First e-EVN science session (Ar, Cm, Tr, On, Wb)
Spectral line observations at 32 Mb/s
January 2004: Disk buffered e-VLBI
On, Wb, Cm at 128Mb/s for first e-VLBI image
On – Wb fringes at 256Mb/s
e-VLBI Milestones: 2004
June 2004: Torun connected at 1Gb/s.
June 2004: network stress test (iperf) involving Bologna, Torun, Onsala and JIVE

6. e-VLBI Milestones: 2005 March 2005: e-VLBI science session
January 2005: Huygens descent tracking, salvage of Doppler experiment
Use of dedicated lightpath Australia-JIVE, data transferred at ~450 Mb/s
February 2005: network transfer test (BWCTL) employing various network monitoring tools involving Jb, Cm, On, Tr, Bologna and JIVE
e-VLBI Milestones: 2005
Summer 2005: trench for “last mile” connection to Medicina dug
March 2005: e-VLBI science session
First continuum science observations at 128 and 64 Mb/s, involving 6 radio telescopes (Wb, Ar, Jb, Cm, On, Tr)
Spring 2006: Metsahovi connected at 10Gb/s

7. 1 Gbps
10 Gbps
155 Mbps
2.5 Gbps

8. Why bother? (change is bad…)
Target of Opportunity - unscheduled observations triggered by sudden astronomical events. This capability will become much more important when LOFAR comes online
Adaptive Observing - Use e-VLBI as a finder experiment
Or, e-VLBI sessions a few days apart, adapt schedules for later observations based on results (rapid results on large sample, focus in detail on best candidates)
Automatic Observing - small number of telescopes observing for extended periods doing spectral line observations of large galactic samples
Interface with other real-time arrays – e-MERLIN, LOFAR, SKA.. Also function as SKA-pathfinder
Bandwidth no longer limited by magnetic media: 10Gbps technology already becoming mainstream
Because we can…

9. 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. No excitement, no drama. JIVE becoming an observatory?
Fourth run: 16 hours at 256 Mbps. However, nearly 25% of time lost to technical problems..

10. First e-EVN Astronomy Publications

11. Current status Technical tests: Current connectivity:
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

13. Tr connectivity bottleneck – (partially) 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.

14. e-VLBI to South America? SMART-1
SMART-1 factsheet
Testing solar-electric propulsion and other deep-space technologies   Name 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     Status Arrived in lunar orbit, 15 November 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.

15. e-VLBI to Sourth America (2)

16. 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?

17. Hybrid networks in the Netherlands..

18. Switch from Cisco to Nortel/Avici equipment has been completed: for now, 7 * 1 Gbps, ultimately 16 * 1 Gbps lightpaths + 10 Gbps IP connection

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

20. EXPReS: getting underway
SA1: new hires at JIVE; two software engineers, one network engineer (finally!), 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.

21. e-VLBI control interface

22. Interface to station Mk5s

23. Runtime control

24. Integrating fringe display

25. Data status monitor

26. Streamlining of post processing

27. Web-based Post-processing

28. Ongoing New control computers (Solaris AMD servers)
Cut down dramatically on (re-)start time
Powerful code development platform
Tightening up of existing code
Other hardware upgrades:
SX optics (fibres + NICs), managed switch at JIVE
Mark5A→B: motherboards, memory, power supplies, serial links, CIBs

29. And coming.. Distributed software correlation
FABRIC: (Huib Jan van Langevelde)
Distributed software correlation
High bandwidth data transport (On part of 4Gbps)
Two new hires at JIVE
And coming..
SCARIe:
Collaboration with SARA and UvA
Distributed software correlation using Dutch grid
Lambda switching, dynamical allocation of lightpaths, collaboration with DRAGON project
JIVE postdoc hired, still looking for UvA postdoc

30. FABRIC components VSIe?? on?? user correlator parameters 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

31. Connectivity improvements
Martin Swany

33. 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

34. Protocol work in Manchester:
(Richard Hughes-Jones, Ralph Spencer & collaborators)
Protocol Investigation for eVLBI Data Transfer
Protocols considered for investigation include:
TCP/IP
UDP/IP
DCCP/IP
VSI-E RTP/UDP/IP
Remote Direct Memory Access
TCP Offload Engines
Work in progress – Links to ESLEA UK e-science
Vlbi-udp – UDP/IP stability & the effect of packet loss on correlations
Tcpdelay – TCP/IP and CBR data

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

36. 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?

37. Protocols (3)
Home-grown version of CTCP using pluggable TCP congestion avoidance algorithms in newer Linux kernels (Mark Kettenis)
Rock-steady 780 Mbps transfer using iperf from Mc to JIVE
Serious problem with new version of Mk5A software under newer kernels

38. e-EVN: the future 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..
Towards a true connected-element interferometer

39. Proposed connection Surfnet-JIVE
External LPs
OME
network
Switch
Mk5
10 G IP
Dynamic capabilities through DRAC
16 GE
N GE