From: <C.Hotan_at_email.protected>
Date: Thu, 15 Oct 2009 09:41:24 +0800

Hi All,

Well done, Simon et al!

Fixing this iVEC border router will make a fair few things easier, it's a real bummer we still don't have a good timeframe on that, it's holding us back a fair bit in terms of the correlator's capacity to accept international data. Disks are fine (USB, MK5, whatever), but it would be really good to be able to use TSUNAMI or something similar to allow us to get data from any high-bandwidth station.
If you've missed the news, basically our router doesn't get on well with UDP (well, in general it drops packets, but that's a real problem for UDP). This hugely bottlenecks our transfer speeds, which is okay for LBA transfers - we're running TCP to try to mitigate this problem - because we can get data in at about the same rate that the telescopes can send it. However when we trialled a tsunami transfer from Bonn, which I believe did require UDP, the packet loss was such that the transfer got exponentially slower over time, and had to be aborted. I don't know the full details, but basically we're waiting on the border router to be replaced, and we *hope* we'll be good to do any transfers after that.

In the mean time, maybe like Steven said, it might be worth investigating using the Japanese correlator?

Great news, anyway, and I hope we can work something out to allow this to be a supported LBA mode!

cheers

Claire

-----Original Message-----
From: owner-vlbiobs_at_atnf.<!--nospam-->csiro.au on behalf of Steven Tingay
Sent: Thu 10/15/2009 7:46 AM
To: Chris Phillips
Cc: Tzioumis, Tasso (ATNF, Marsfield); Simon Ellingsen; VLBI observers
Subject: Re: Fringes from Australia-Japan VLBI test
On Thu, Oct 15, 2009 at 7:31 AM, Chris Phillips <Chris.Phillips_at_csiro.<!--nospam-->au> wrote:
>Or we could send the data to Japan to correlate :-)

Could be a good idea.

>
>But I think the data transfer issues are much more or a problem now than
>data format.
>
>Cheers
>Chris
>
>------------------------------------------------------------
>Chris Phillips
>CSIRO ATNF     eVLBI project scientist
>Office: (+61) (0)2 93724608      Mobile: (+61) (0)439487601
>
>
>
>On 15/10/2009, at 10:28 AM, Steven Tingay wrote:
>
>>Hi Tasso,
>>
>>Note that if proposals are accepted, they have to be supportable at
>>the correlator in a routine way.  This will not be possible until the
>>format and disk media issues (or data transfer issues) are sorted out.
>>So, this bears a little bit of thought before progressing too far.
>>
>>I agree that proposals in the system will be the impetus to sort out
>>the issues, but a bit of forethought will ease the way.  So, I suggest
>>we think about some formal tests to establish a routine data path.
>>
>>Cheers, Steven
>>
>>On Thu, Oct 15, 2009 at 7:15 AM, Tasso Tzioumis <Tasso.Tzioumis_at_csiro.<!--nospam-->au>
>>wrote:
>>>
>>>Hi Simon,
>>>
>>>Great news. Well done...
>>>And I think you are right and it is the first time the LBA and VERA
>>>antennas
>>>have observed together.
>>>
>>>It will be great to progress beyond simple tests. As far as the LBA is
>>>concerned we will be happy to see proposals in the system that also
>>>require
>>>the JVN. If I recall correctly, under the APT guidelines the same
>>>proposal
>>>should go to both networks with all the scientific and technical details.
>>>If
>>>they both approve it, then the respective schedulers can coordinate for
>>>time.
>>>
>>>I appreciate that there are technical issues to solve like formats, but I
>>>still think the key is good proposals into the systems.
>>>
>>>I look forward to working in this mode.
>>>
>>>Cheers
>>>Tasso
>>>
>>>On 15/10/2009, at 1:40 AM, Simon Ellingsen wrote:
>>>
>>>>Dear LBAers
>>>>              In late May Hobart participated in a 2 hour test
>>>>observation at the
>>>>end of a JVN methanol maser VLBI observing session.  We observed a
>>>>number of continuum calibrators and equitorial methanol maser sources
>>>>with a 4 MHz bandwidth and centre frequency of 6.668 MHz.  Hobart
>>>>observed dual polarization, while the Mizusawa VERA antenna and the
>>>>Yamaguchi 32m recorded LCP only.  Mareki Honma arranged for conversion
>>>>of the recorded disk-based data from one of the K5 formats into
>>>>Mark5B, while at Hobart we recorded using the standard cdisko
>>>>recorder, but with data saved in Mark5B format rather than the
>>>>standard LBA format.
>>>>
>>>>              After lots of help from Chris Phillips to get the DiFX
>>>>input file
>>>>correct, I have finally been able to get the first hour for the Hobart-
>>>>Mizusawa baseline correlated using version 1.5 of DiFX.  Over that
>>>>period we observed two calibrators and two maser sources and we have
>>>>fringes from J0609-1542 and the two methanol masers G188.95+0.89 and
>>>>G213.70-12.6 (Mon R2), which are shown in the attached postscript file.
>>>>
>>>>              I think that we have previously had Australia-Japan
>>>>fringes
>>>>in
>>>>recent eVLBI experiments and 20 years or so ago in some Mark II
>>>>experiments (perhaps also some VSOP experiments).  However, I think
>>>>that this is the first time we have had fringes to any of the VERA
>>>>stations from Australia?
>>>>
>>>>              I think it would be good to arrange a full-scale
>>>>Australia-Japan
>>>>observation in the not to distant future, as I'm sure that there are a
>>>>range of experiments both maser/line and continuum which could benefit
>>>>from long N-S baselines?
>>>>
>>>>Regards
>>>>
>>>>Simon
>>>>--
>>>>Simon Ellingsen : Senior Lecturer Physics & Astronomy, University of
>>>>Tasmania
>>>>Currently : Humboldt Experienced Research Fellow, MPIfR, Bonn
>>>>email : Simon.Ellingsen_at_utas.<!--nospam-->edu.au
>>>>WWW   :
>>>>http://fcms.its.utas.edu.au/scieng/physics/pagedetails.asp?lpersonId=681
>>>>Phone : +49 (0)228 525 392 (work)      +49 (0)1522 374 5728 (mobile)
>>>>
>>>><HOB_MIZ_FRINGES.PS><ATT00001.txt>
>>>
>>>----------------------------------------------------------------------
>>>Tasso Tzioumis,  Australia Telescope National Facility, CSIRO
>>>Location: Cnr Pembroke & Vimiera Rds, Marsfield, NSW, 2122, AUSTRALIA
>>>Post:     PO Box 76, Epping, NSW 1710, AUSTRALIA
>>>Phone:    +61 2 9372 4350   Fax:  +61 2 9372 4450 or 4310
>>>Email:    Tasso.Tzioumis_at_csiro.<!--nospam-->au
>>>URL:      http://www.atnf.csiro.au/~atzioumi/
>>>----------------------------------------------------------------------
>>>
>>>
>>>
>>>
>>
>>
>>
>>--
>>* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
>>Professor Steven Tingay
>>
>>Premier's Fellow
>>
>>Deputy Director
>>ICRAR
>>
>>Deputy Director
>>Western Australian Radio Astronomy Centre of Excellence
>>
>>Director, Science and Operations
>>Curtin Institute of Radio Astronomy
>>
>>Department of Imaging and Applied Physics
>>Curtin University of Technology
>>Bentley, Western Australia
>>Australia
>>
>>Street address:
>>Brodie Hall building
>>1 Turner Ave
>>Technology Park
>>Bentley 6102
>>Western Australia
>>
>>Email:  s.tingay_at_ivec.<!--nospam-->org OR s.tingay_at_curtin.<!--nospam-->edu.au
>>
>>WWW: http://astronomy.curtin.edu.au
>>
>>Phone: +61 (0)8 9266 3516
>>
>>Mobile: +61 (0)425 771 856
>
>

-- 
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Professor Steven Tingay
Premier's Fellow
Deputy Director
ICRAR
Deputy Director
Western Australian Radio Astronomy Centre of Excellence
Director, Science and Operations
Curtin Institute of Radio Astronomy
Department of Imaging and Applied Physics
Curtin University of Technology
Bentley, Western Australia
Australia
Street address:
Brodie Hall building
1 Turner Ave
Technology Park
Bentley 6102
Western Australia
Email:  s.tingay_at_ivec.<!--nospam-->org OR s.tingay_at_curtin.<!--nospam-->edu.au
WWW: http://astronomy.curtin.edu.au
Phone: +61 (0)8 9266 3516
Mobile: +61 (0)425 771 856

Received on 2009-10-15 12:41:43