[AG-TECH] Packet Loss

[Chris Kendrick]

On Thu, 2006-08-24 at 13:35 +0100, Piers O'Hanlon wrote:
> Hi,
> 
> You could firstly just test direct unicast rat and vic sessions
> between the two sites and see if you get the same packet loss. As
> Marcus suggests you can use the packet info in vic and rat. You could
> try altering the port numbers you use and see if it makes any
> difference. Also does it happen all the time or just certain
> days/time-of-day/month?
> 
> If you do see loss then you could try running traceroute from both
> sides to try to see where the packets are getting lost. It will be
> tricky to diagnose exactly where the problems are since you're getting
> unidirectional loss but it should give you a rough idea. Under Linux
> "traceroute" uses UDP packets as default - you can specify the base
> port nunber with -p option. However Windows "tracert" uses ICMP
> packets so you may see different results.
> 
> If you don't see loss then it maybe the unicast bridge you  were using
> was being periodically overloaded.
> 
> Piers.

Thanks Piers

I will give those steps a go if the packet loss shows up again and post
how it goes.

Chris Kendrick
VPAC

> 
> On 8/24/06, Chris Kendrick <kendrick at vpac.org> wrote:
> > Hi All
> >
> > I was running an AG session between, VPAC (Melbourne, Victoria,
> > Australia) and The University of Bristol in the UK Yesterday.
> >
> > For some reason I was getting ~5sec patches of huge packet loss (as
> > shown in the RAT reception quality matrix) roughly every 3 minutes from
> > them (voice went extremely choppy), but they were always receiving good
> > audio from me.
> >
> > I was running AG2.4 compat they were running inSors. and we had met in
> > the University of Bristol VV
> >
> > I also Started a desktop AG2.4 compat at VPAC and joined the session, I
> > received packet loss from Bristol and from the original VPAC node, (due
> > to the VPAC nodes both connecting to the Bristol unicast bridge, the
> > traffic from the other VPAC node was obviously traveling to Bristol and
> > Back and getting packet loss on the return trip)
> >
> > also we tried switching the Bristol inSors node between unicast and
> > multicast, and we also tried going to the University of Leeds VV and
> > having the Bristol node switch between unicast and multicast again.
> > Still got exactly the same packet loss pattern only coming from Bristol
> >
> > My question is what tools tecniques can I use to further diagnose what
> > is going wrong if it happens next time?
> >
> > Any advice gratefully received.
> >
> > Chris Kendrick
> > VPAC
> >
> >