Hi,
Please compare the latency variation etc
1. Network PC to ISP gateway
2. Firewall to ISP gateway
Regards,
Jithin K
On Tue, Apr 19, 2011 at 7:55 AM, Girish Venkatachalam <
girishvenkatachalam at gmail.com> wrote:
On Mon, Apr 18, 2011 at 7:41 PM, Preetish <preetish.tripathi at gmail.com>
wrote:
Hello Everybody
I am not sure if this is the correct forum to discuss this so kindly
ignore this email if you find the topic irrelevant for this forum.
Such long mails are a bore. It is like a novel. ;)
Please write short sweet mails.
Recently we have started facing issue in our network where in if we
initiate a Video Conference ( we use Video Nation Life Size VC
equipment ) we see packet loss which goes upto 40% and jitters which
goes upto 100ms . This packet loss is only on incoming packets. So the
voice and video quality is very bad at our end however the person at
the other end is able to see and hear us very clearly. If we look at
the VC statistics, we can see that we are uploading at around 1 mbps
however the download starts at 1 mbps but then drops down to 100kbps
within seconds . Same is the case with skype calls .
Good. ;)
Normally download speeds are higher.
Now one of the reasons I am posting over here is that all our network
traffic goes via a debian box ( 5.0.4 ) which acts as the firewall.
The cpu utilization on the firewall is not high at all. This debian
box also acts as a vpn server and we have two VPN tunnel to connect to
our office in the UK . Also we use quagga ( ofpfd ) to route traffic
over the tunnels. Also I have checked statistics ( ethtool -S eth1 )
of eth1 ( which is our internet link ) and it shows no error either on
rx or tx . All our internal network are on various vlans on eth2 and
there are no errors on it too.
Good.
We have reported this issue to our ISP and they changed our route a
couple of times ( even the reverse route was changed ) however it did
not resolve the issue. Finally we bypassed our firewall and put the VC
equipment on a public IP ( its on a different subnet than our firewall
) and we are not facing the issue any more ( I still have to check
which route it follows to the Video Nation gateway and compare it with
the route our firewall follows ) .
Okay.
Now I know that there has been no change in our network which could
have caused this issue. However now the ISP says that the issue might
be because of our firewall .
Quite possible.
Can someone let me know if there are any tools which can help me
troubleshoot this issue. Something that can let me know the point at
which there are packet loss. Also please let me know if I should be
looking at .
There is not enough information in this mail albeit long.
And this is a complex issue.
Some ways to attack this are:
1) Try turning off connection tracking and other stuff in the Debian
box and see
how the network performs
2) Try a simple command line wget or something and find out what is
happening.
3) Monitor the bandwidth in the Debian box and afterwards. Find out if
something
goes wrong in between
There are 100 other ideas I can give.
But you have to do it.
-Girish
--
G3 Tech
Networking appliance company
web: http://g3tech.in mail: girish at g3tech.in
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