voip Bust of Static issue

[snooter]

Hello.

Just so whoever reads this knows, i've already been through a TAC case and they didn't relove it completly.

Problem: Off-net callers hear a short "grrrrrrrrrrrr" sound the second one of my voip users pick up the phone. Before they even say hello, they callers hear the noise and then it stops and the rest of the call is fine.

Here's the call flow: A customer calls my Texas office 800# and that call comes into our Iowa office vg200 and goes directly to our CCM's. Once there, the CCM translates the call to a 4401 extension, which is the receptionist in our Texas office. The receptionist answers the call and then transfers it to the appropriate user in the Texas office. As soon as that user picks up the phone, the outside callers here this "grrrrrrrrrrrrrrrrrr" sound that lasts no more than one second. Then, the rest of the call is fine!

No MOH or anything of that sort..

CCM 3.3(3)

Phone loads are updated to most current.

Plenty of bandwidth on the frame relay lines.

No noise is produced for local callers. Only when it comes down the frame.

No noise between users in the same office or any other office calling the Texas users.

Weird stuff...like I said, TAC hasn't been able to figure this out.

Thanks for any help or ideas anyone.

Scott

[jasyoung]

As a total random guess, try scaling your initial jitter buffer up on the gateway. The default is something like 40 or 60ms. If your QoS isn't set up just right and you have a lot of jitter, your gateway might be under-running on available voice traffic to play out until it decides that it's a good idea to scale the size of the buffer up.

vg200(config)#mgcp playout adaptive 120 40 250

The parameters are the initial, minimum and maximum values used for the adaptive jitter buffer. We start off using the initial value and we can float up and down between the minimum and maximum values based on network conditions.

See if the voice distortion sounds like anything on this page, especially "robotic voice":

http://www.cisco.com/warp/customer/788/voice-qos/symptoms.html#robo

If the playout buffer adjustment doesn't help, post here again and attach to your post the output of "show version", and "show call active voice brief" while you have at least one call in progress from your VG200 to a phone in your Texas branch. Include the IP address of that phone so that we know which call it is out of the show command output.