[AG-TECH] What's typical loss on multicast video/audio?

[Steven Woolsey]

We had a similar problem.  Turned out that the switch which connected 
our site to the outside world was throttled back from full capacity, and 
the AG was the only thing we had which would push network loads above 
that limit, so it hadn't been seen before.  Took a tech from the company 
that made the switch to finally figure out what was wrong and change 
it.  Might be something to look at.

Steve Woolsey

-- 
Steven Woolsey
woolsr at inel.gov
Senior Engineer/Scientist
Visualization Engineer
INEEL 



John I Quebedeaux Jr wrote:

> I have been reporting to my networking staff that I've been seeing 
> losses on the order of 1-15% on my incoming multicast video/audio when 
> participating in events and that those participating do report that 
> they see some loss coming from me as well. Sometimes its only around 
> 2-3% on average - other times its 5-10%.. and jumps up and down. This 
> happens regardless of the node I operate (we have a permanent 
> installation in one building and a PIG in another building).
>
> Testing, by inserting our PIG into various points into our campus 
> network and observing the general trend in our venue with some helpful 
> participants and by general observation in the AG Lobby, seems to 
> indicate that while we have a little loss (<1%) across core 
> backbone/network enforcer/intrusion detection device - we have a 
> greater loss coming from our state network. They tell me we're the 
> first in our state to utilize multicast on the network... so perhaps 
> there are some issues still to be worked out.
>
> The question my network guy asked me was if this loss was typical or 
> atypical of what other sites doing Access Grid/Multicast activity 
> usually see. I would maintain that it isn't.... but have to ask the 
> question out there for a reality check.
>
> Lately, it seems, that 3 out of 4 events I run are with sites that 
> have multicast issues so our quickbridge comes in real handy. For 
> those where we do have multicast connectivity - this missing packet 
> loss (as reported on the vic rtp stats) is a constant nag.