Poor video Conferncing Quality with Cisco Video Terminal Adapter Version 2

[shyams]

We are running a Video Conference Network with Picturetel Concorde and Venue 2000 systems spread across India and US. These systems connect to the TCPIP network using Cisco Video Terminal Adapters. Recently we had upgraded this to ver 2.0.

However a)The quality of the video conferencing is not acceptable even for a 384 kbps call on a 512 kbps / 2 Mbps leased circuit with 10 percent utilization. This happens even when we dedicate the entire bandwidth for Video Conferencing.

b)The audio and Video quality further degrades over a period of time.

The quality of the link is found to be good by our service provider. We have established the necessary QOS using Class based WFQ.

This has seriously affected our Video Conferencing facility. Would like to know if this combination is in use elsewhere and if there are any solutions for the same.

Thanks

shyam

[sachon]

A few things you may want to try... First, check with PictureTel about the appropriate code on the Concordes and Venues. While 2.0 is the latest from Cisco, PTEL has specific code for their 320 codecs to work with VTAs...2nd, check the setting on the PTELs for codec negotiation. You want to make sure that H.263 video is being negotiated across the path. H.263 generally looks better than H.261 at the 384k range... 3rd, quality of SP link. Not sure what you mean by "good" quality but video wants specific characteristics - i.e., sufficient b/w >420k for 384k video calls + low latency <150ms delay + zero jitter. In addition, you may consider using a priority queue for video as even WFQ may starve a video call if the number of concurrent flows grows beyond a certain number as a function of link speed. A priority queue should maintain the flow of video traffic better than WFQ...I have your same h/w set-up at several firms with good success. I believe that your problems are configuration or s/w related. Good luck

[rkumarr]

1) H.263 is not supported by CISCO VTU.

Are there plans for Cisco for their VTU's to support H.263.? I would like to have the reason behind support of only H.261 on VTU.

We configured a priority queue for Video traffic and experiencing better results in terms of quality.

2) If we need to run a conference at 784Kbps, Is it mandatory to have H.263 or it can work well with H.261 itself.

Kindly advise.

[shyams]

Also, how do you make T.120 work with Cisco VTA's?

Is it possible to have atleast share a presentation with Picturetel Concorde VTA combination?

Switching over from ISDN to IP Conferencing with Concorde /VTA is another problem.

Thanks

shyam

[prgreen]

I agree with the previous messages. However, run Nettach on two PCs from end to end, Nettach, licensed by PictureTel but available for free, will tell you if the link meets minimum requirements. Download the Nettach15.exe file from ftp://ftp.radvision.com/OnLAN_Util_SW/