Static and background noise on voip calls

Steve Baker · ‎02-21-2014

We currently run CUCM 6.1 for our voip solution. We have multiple sites connected which all use H323 voice gateways running on Cisco 2821's.

We've recently setup an H323 voice gateway in a new regional office. It is using a Cisco 2821 with a PVDM32 installed. It links back to our main office over a point to point VPN using an internet line which is 4MB up and 4MB down.

When we make a call from our regional office to our main office the call goes through however there is lot of loud static on the line. This appears to only be a one way issue though. To the user in the regional office, the call is clear, for the user in the Main office you can barely hear what is being said for the amount of noise on the line. The same issue happens if the main office calls the regional, the regional office is still clear where as the main office has static.

I have tried disabling VAD on the dial peers but this appears to have made no difference. I am wondering if there is something that I need to configure with the DSP resources to resolve this issue?

First time setting up a gateway myself so probably done something dumb. Any troubleshooting help or pointers would be appreciated. I have attached the config in case this helps.

Thanks

Steve

bernhardczapp · ‎02-21-2014

Config looks okay so far.

Did you check the isdn interface for errors? (show controller e1)

Maybe there is a problem with the E1.

By the way:

You are using H.323 but have configured "dtmf-relay rtp-nte". CUCM doesn't support rtp-nte with H.323 gateways, use h245-alpha... or h245-signal instead.

Steve Baker · ‎02-21-2014

Thanks for the pointer on the DTMF relay, I have updated it accordingly.

At the moment the ISDN line is disconnected. Currently theat office uses an Avaya system and its being used for that. The kit we are putting in is the planned replacement.

The calls we are testing are going over the WAN, extension to extension. I did wonder if as its going over a point to point VPN if their may be something on the Cisco ASA causing the issue?