[AG-TECH] Delays in audio/video arriving

John I Quebedeaux Jr johnq at lsu.edu
Mon Apr 28 12:55:55 CDT 2003

I've got one for anyone who might understand/know/guess what causes 

Our AG 1.x node has been up since December but only since two weeks ago 
have our multicast streams been visible outside of our state network 
via I2 (i.e. we've been receiving all along but not sending properly).

My problem is that my outgoing streams are delayed - incoming fine. 
Outgoing are delayed... at different rates and as bad as 1-10 seconds 
later. Typically 2-5 seconds and it varies.

When I test (with anybody outside our campus network) - I am receiving 
video and audio pretty well. I get the occasional studder/drop in audio 
but generally it's very clear and the RAT shows maybe 1-2% loss at 
times with my receiving.

Outgoing is another issue. I'll get as much as 50-60% loss at times 
that the RAT tells me and other times it is just 1-10%. Sometimes it 
clears up and then degrades again. What is really interesting - and I'm 
not much of a network guy - but my audio and video streams are 
delayed... in that they arrive anywhere from instantly to 10 seconds 
later to the other site. Not much loss actually... although the audio 
will end up choppy as a result.

What's even more interesting is that one camera video will be less 
delayed (or even not delayed) while the others are delayed at different 
rates. The audio is delayed (or not at times) as well. I've seen delays 
as high as 10 seconds. It happens from both my node and my pig node. 
Between my two buildings (i.e. between my node and my pig) I don't see 
this happening.

I'm trying to get my network support on campus to look into this but 
they don't respond well unless I can tell them what and where I think 
the problem is. Multicast was enabled just for this application - so 
they are new to this.

So... any suggestions on how I might troubleshoot this or if someone 
might have an idea of what might be happening (someone has seen this 
before) I'd appreciate if you dropped me a note to give me a direction 
to head me in.

I do know our on campus equipment is Cisco... I'm supposedly on a 
gigabit 8 port switch to our campus fibre and then out to I2 (via LaNET 
here in the state) onto the Abiliene network. My AG node has Linux 7.3 
for the audio and video capture and windows xp for the display.

Anywhere to point me is appreciated.

John Q.
John I. Quebedeaux, Jr.
LSU Biological Sciences
Computer Manager/LBRN
131 Life Sciences
e-mail: johnq at lsu.edu
web: http://lbrn.lsu.edu
phone: 225-578-0062
fax: 225-578-2597

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