XMPP as VOEvent transport

[Jean-Paul Le Fèvre]

Hello, especially John,

As you may know the Svom project was frozen a couple of years ago due to budget difficulties (as usual). Fortunately the money has been found and the spacecraft will be launched by the end of 2021. As a consequence, on the ground segment, we have to work hard to get ready for this date since there is a pretty big amount of software to develop.

Since the beginning of the project I've been promoting usage of VOEvents to distribute our alert messages and I've convinced my Chinese colleagues to use this technology. We have rapidly found an agreement and we have started to play with XMMP openfire servers quite successfully.

Some preliminary pieces of code are available at http://svomtest.svom.fr:8000/messaging/
(It is a work in progress and there is no guaranty whatsoever that this code is still working properly)

Two aspects still need to be studied :
- synchronization between 2 servers (the future one in Paris, the other one in Beijing)
- the pubsub functionalities

My goal is to have some results to validate our approach available by the end of next spring (A Preliminary Design Review will take place in June 2016)

Apart these technical questions I'm facing other difficulties:
- How to make VOEvent concepts well understood and used by scientists ? These folks are very conservative and sometimes lazy : moving from GCN to VOEvent is really hard for them.
- How to interpret correctly the VO standards (possibly in draft version) ? Specializing VOEvents and especially VOEventStream for a specific mission is not so easy.
But I guess that these questions could be the subject of new other threads.

Regards,

--
Jean-Paul Le Fèvre jean-paul.lefevre at cea.fr – CEA Irfu
Svom French scientific centers project manager

-----Message d'origine-----
De : voevent-bounces at ivoa.net [mailto:voevent-bounces at ivoa.net] De la part de John Swinbank
Envoyé : jeudi 24 septembre 2015 14:35
À : IVOA List VOEvent <voevent at ivoa.net>
Objet : XMPP as VOEvent transport

Dear all, but particularly Jean-Paul,

A new thread on this, since I don’t want the discussion of VTP to turn into a more general-purpose discussion of how one could or should transport VOEvents. However, I was interested to hear that Svom is pressing forwards with XMPP as a distribution mechanism: I’m aware of that being discussed several years ago, but hadn’t seen any news in some time (I’m out of the loop; sorry).

I’d be curious to know what the latest status of this is. Is there code available? A “getting started” document describing how it works? Any thoughts on scaling to large numbers of events, or large event packet sizes, or bulk distribution? Does it help address issues regarding event authenticity?

VTP is useful as a minimal baseline, but I have reservations about it, particularly in terms of scalability, and I’d love an update on other work in this area.

Cheers,

John
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