cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
613
Views
0
Helpful
4
Replies

Polycom Viewstation to IP Phone or VTA

kbyrd
Level 2
Level 2

I am testing video between an H.323 Polycom Viewstation (version 7.4.5) and Call Manager 4.1.3 SR2. On the Call Manager side, the clients could be an IP Phone for a audio-only connection or with a CVTA for a video conference. I can call from the CVTA to the Polycom with no problem, however, I cannot successfully call from the Polycom to the Call Manager. (fast busy). For testing, I have all endpoints in the same DP with G711u audio. Now, I can call to/from a NetMeeting client with no problem. Here is what I think the problem is and I'm hoping there is a simple resolution: The Polycom has two audio codec setup options: G722 and G728. You establish a Bandwidth threshold in the set up of the Polycom to tell it which codec to use - below the threshold use G728. Above use G722. I think that there is a codec negotiation issue when the Polycom calls the Call Manager and not vice versa. Also note that the Polycom can call to/from the NetMeeting. I have tried defining the Polycom as an H.323 Client and via a Gatekeeper Trunk. Exactly the same issues. The only way I can get it to work is to have a Cisco Gatekeeper (IOS 12.3.12) proxy the call to the Call Manager. Then I can call to/from the Polycom from an IP Phone or the CVTA. This leads me down the path that the Call Manager has a codec negotiation issue if a Call comes in initially as G728 or G722.

I have verified CSSs and PTs. That is not the issue.

With this info, can someone recommend a command on the Polycom to setup calls with G711 - or a Call Manager service parameter tweak that would negotiate to G711u? Thanks.

4 Replies 4

jleon22
Level 1
Level 1

This is an interesting question. Maybe a transcoder is needed?

jcounter
Level 1
Level 1

I'm having the same problem, did you ever get this resolved?

Thanks

JCounter

Hi.The version of the Polycom I'm using is a Polycom Viewstation 512K running Release 7.5.4 - 04 Mar 2005. It appears that it will negotiate G729 and G722 when it sets up a call. It will also negotiate G711 when another endpoint calls it. I tried several options...the one that worked is where I found an old 2600 router and made it the Gatekeeper proxy for the Polycom. This is pre IP-IP gateway code. I think I was running 12.3.17a IX code. So I moved the video to it's own Gatekeeper. (The Call Managers have two gatekeepers.) I set up all of the inter-zone configurations....and it worked. There must be some h323 negotiation attribute in the Polycom that breaks the ability to talk to the Call Mgr. Put a Cisco proxy in-between, and things start to work. Sorry I don't have a more technical answer than that.

Thanks. That helps, as we dont have a Cisco Gtkpr inline yet. Only a Radvision.

Thanks for the explanation!

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: