Group 300 Intermittent no video and audio

[Anonymous]

Hi Polycom Community,

First post here as I have an issue that I have been unable to solve. 

My client has multiple mobile medical carts using the group 300 with wireless connection to their network.

Using Cisco SAP units for wireless which work great, wireless is not the issue as far as I can tell.

I believe it is related to the firewall but all ports are open and it works some of the time.

I can connect to external LAN sites most of the time with no problem, other times, that same site will connect but no audio or video. 

We are using H.323 no SIP. Upgraded to 4.2 software on all units yesterday. 

Network monitoring of logs shows no denials of ports or errors. 

Am I correct in saying that the codec uses different ports everytime it makes a call. I have all units set to use fixed ports. Thinking if this is correct that some ports are not passing data. 

Why would it work some times and not other.

We are using NAT 1 to 1 and the VTC test site reports the proper IP and does call the units back most of the time. 

Brought a new system up this morning and made test calls back to the main I.T. office and first call worked. Tech on the far end said my public IP never came through, he says he saw his firewall IP. He tried to call me and I got no video or audio. I immediatly tried the VTC test site and it worked just fine with call back from test site. 

Sorry if this has been addressed in a previous post, I searched and only found posts about systems that would never connect. I can connect most of the time, just not all the time. 

[Anonymous]

When the call does not connect what does the stats show as far as the algorithm being used on the receive side?

[Anonymous · Accepted solution]

Turns out is was the H.323 setup in the firewall. Video call would work most of the time and no video or audio other times. Disabled H.323 in firewall and all is good.