[AG-TECH]Fun with Venue Servers and NATS

Michael Miller mimiller at ncsa.uiuc.edu
Mon Mar 12 10:46:03 CDT 2007


If you look at the NATted site's Producer vic, do 
you see their video there?  You will need to 
unmute it.  What you describe occurs because only 
on app can receive data from a port at a 
time.  Since you have a single connection with 
the bridge, in order to get past the NAT, the 
first vic launched(in this case the producer) 
steals the data from the second vic.  Often you 
may see "waiting for video" in the consumer 
vic.  This only occurs in single machine nodes or 
any node that runs the producer and consumer vics on the same machine.

The solution is to look for the missing video 
streams in the Producer vic, unmute them and open them from there.

Let me know if you have questions.


At 10:03 AM 3/12/2007, john langkals wrote:
>Hello AG Tech,
>There have been a few emails discussing NATS and 
>Access Grid connectivity on the list lately.  I 
>am trying to setup and Access Grid at another 
>site.  Trying to go through their NAT on my end 
>is no problem. I see all external and local site 
>video just fine.   The only issue is the NATted 
>site will get most external video streams that 
>are connected but they do not see their local 
>video.  Also as they restart their video, more 
>remote site video streams appear.  Just no local 
>video. This is no surprise as NATed routers do 
>not have true end to end connectivity and it may 
>break some IP protocols such as UDP. I am 
>testing in the NCSA Lobby (venue server) and as 
>this site does not support off site multicast, 
>they are bridging unicast.  I have tested this in AG 2.4/3.0.2.
>My question is
if I would setup my own venue 
>server, would I be able to pull off any tricks 
>for both sides to transmit and received video 
>just between our two sites? Hoping only just 
>connecting between two sites would help out some 
 Is there any way to build a stripped down 
>venue server that would pull off any port 
>forwarding tricks?  I remember there was a 
>project called AG Connector but I can’t find any 
>information about it.  To anyone’s knowledge, would this be useful in my quest?
>John Langkals
>Systems Manager
>Ohio Center for Technology and Science
>M2021 Physics Research Building
>191 West Woodruff Avenue
>Columbus, Ohio 43210
>614.292.6957 Office
>614.327.3732 Cell
>614.292.7557 FAX

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