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New Member

problems with external calls

hi @ all,

our problem is, if a call comes from extern to our Cisco Voice over IP System we hear the external caller 2 sec later as he us.

The connection from the external caller is there because he can hear us but we can hear him first in about 2 - 3 sec.

Is that a problem with our Callmanager (version 3.2.2c) or with the voice gateways?

I hope anybody can help me


New Member

Re: problems with external calls

I think this is a problem on the voice gateways. You can check this by doing internal IP to IP phones test, then you can exclude the gateways.

We have had some similar problems and you need to check the IOS version of the gateways with the compability matrix.

You can view this in the callmanager debuggings with the timestamp of the mediaopen ...

Hope this helps


Cisco Employee

Re: problems with external calls

I assume this is a H.323 gateway.

1.The "rtp send-recv " command may help. It causes the return RTP stream to

be setup quicker.

2. You didn't mention what platform, but if you have 4224, then check the following compatability matrix:

3. This may be due to high latency of the network between the gateway and Callmanager or loss of H.323 packets due to congestion of the network.

If congestion is occuring QOS may help. If due to network latency, either use

an MGCP gateway or wait for CM 3.3(x) which will support H.323 faststart (which makes the setup more efficient), or improve latency in the network.