[AG-TECH] Re: Possible firewall / NAT issue

[Dioselin Gonzalez]

Jason,

I have had the exact same issues that you describe, except for the 
losing audio when changing venue.  What made a big difference in our 
site was the unicast bridge: with some bridges we'd get only a few video 
sources, with others we couldn't get audio, etc.  The NCSA, Argonne and 
LSU bridges are the ones that work best for us.

Dio.-


Jason Bell wrote:
> Hi guys
>
> I have been helping a site attempt to get their Access Grid up and
> running, in which I have stumbled across a couple of issues that I hope
> someone could possibly assist with.
>
> Firstly, let me state that I suspect the issue is related to either the
> firewall and/or being behind a NAT network.
>
> System information for AG Node
>
> *	Single AG node running Windows XP
> *	Windows firewall turned off
> *	AG 3.2
> *	Unicast only
> *	Connected to a NAT network
>
> Initially the problem was that the site couldn't see any other sites
> connected in various venues.  Anyway, after some testing, we found that
> if the site was transmitting audio, it would then be able to receive
> audio.  (This was in the APAG lobby).
>
> We also found that if the site was running a consumer process only, the
> site would not receive any video in "vic".  After plugging in a USB
> webcam, and running both a video consumer and video producer, everyone
> else's video would then appear, but only in the producer service only
> (therefore had to un-mute the streams).
>
> Another interesting thing that occurred is that when using a video
> service only, no incoming video could be received (whether transmitting
> or not).  Therefore we had to run the other 2 services to receive video
> from other sites.
>
> Also, if we moved to a different Virtual Venue, audio would stop
> receiving...  The participants would be listed, but incoming would
> always be 0.0 b/s.  Transmission was fine!
>
> Note, that we tried various unicast bridges and the same issues would
> occur!
>
> Now the site is behind a corporate firewall running IPTables, with ports
> 50000-52000 open for both udp and tcp for input.
>
> Given that it works perfectly in the APAG lobby, one would assume that
> the firewall is "sorta" configured correctly, otherwise it wouldn't work
> at all.  I initially though it might be a "Stateful" firewall issue, but
> now I am beginning to think the issue is more likely a Nat issue.
>
> Therefore, my question is, has anyone else seen similar issues and what
> did you have to do to resolve the problem?
>
> *	Did you have to do some special type of packet forwarding?
>
> Unfortunately, the site I am assisting is nearly 2000 klm's away, but if
> you have any advice, I would greatly appreciate it.
>
> Thanks very much for your time,
> Jason.
>
> --------------------------------------------
> Jason Bell, B.I.T. (Honours)
>
> Research Systems Support Officer
> Information Technology Division 
> CQ University Australia
>
> Australian Research Collaboration Service
> http://www.arcs.org.au/
>
> E-mail : j.bell at cqu.edu.au
>          jason.bell at arcs.org.au
> Work   : +61 7 4930 9229
> Mobile : 0409 630897
> Postal : Building 19
>          Central Queensland University
>          Bruce Highway
>          Rockhampton, Queensland, Australia, 4702
> --------------------------------------------
> Patience is a virtue.
>
> But if I wanted Patience,
> I would have become a Doctor.
> --------------------------------------------
>
>
>   


-- 
Dioselin Gonzalez
Research Scientist
Louisiana Immersive Technologies Enterprise (LITE)
537 Cajundome Blv.
Lafayette, LA 70506
www.lite3d.com
Office: +1 (337) 735-1393
Email : dioselin at lite3d.com