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New Member

H323 Video conferencing over WAN

We have the following setup for a pilot Videoconferencing project running over the WAN. The video quality in general is not satisfactory.

1) Tandberg 880MXP registering to local gatekeeper. Another Tandberg 770MXP registering to the above gatekeeper.

2) The 770 MXP is located in a remote office, connected via a VPN link.

3) The available bandwidth is 1.2M and the link is not used much for data or voip, so we get about 1M always for video.

4) the WAN link is a ATM connection to the remote ISP, in the headquaters here the link bandwidth is 30M.

5) The tandberg 880 and 770 are on separate internal subnets.

Problem

1) The video quality even with a 256k video call is average with lots of pixalation and some packet drops.

2) The average delay is 40ms and avergae jitter is 8ms.

3) The endpoints register about 8% video packet loss/drop.

4) The call never drops, but constant packet loss occurs.

5) An iperf test run over the same link, showed a consistent 1M bandwidth with 0.01% packet loss in general.

We have tried various qos policies and also tried running without a VPN over GRE tunnel. But the quality is still unsatisfactory.

Side notes:

1) A call to other locations tends to be very good. Probably pinning the issue on the wan link. but we are unable to find the real cause.. especially with iperf tests working fine.

Any help, leads or directions would be extremely helpful.

Thanks

Manish

3 REPLIES
Silver

Re: H323 Video conferencing over WAN

New Member

Re: H323 Video conferencing over WAN

Did you ever get this issue resolved? We have something similar going on.

Hall of Fame Super Gold

Re: H323 Video conferencing over WAN

Hi,

iperf only shows packet loss, while the the endpoints are suffering from late packets also.

Are you doing qos pre-classification to mark the DSCP value in VPN outer header too ? That would give ISP a chance of applying some QoS to your video, at least they can be asked to do so.

Hope this helos, please rate post if it does!

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