1-way audio problem

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Mar 31st, 2008
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hi guys, I have 1-way audio..far end can't hear me....connection: US to UK, over public ip.....my end/US..cisco 2811....>cisco switch2900...>FW(ASA)...>internet, codec g711ulaw on both ends...UK side:internet....>soft switch (Veraz)...any ideas what may be causing this 1-way audio problem...I have a simple config on my 2811, no QoS/CoS yet........

The farend told me today that they do not see that we are sending rtp msgs...

Thanks in Advance,


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Rick Morris Tue, 04/01/2008 - 08:38
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Have you tried changing the codec to g729, 711 requires a lot of overhead and bandwidth and typically run onnet in the office. I assume this is CME?

Is it between offices or between specific devices? Periodic?

winston123 Tue, 04/01/2008 - 08:53
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I have not tried that yet, I will try....it is between offices..network setup...voice server (with dialogic t1 card)---->2811--->cisco 2900--->FW (ASA--->internet...

The farend is saying I am not sending rtp packet/msg..

note: I have the 2811 bandwidth for myself.it is just one test call i place over it.


Rick Morris Tue, 04/01/2008 - 08:55
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So the call set's up, rings the far end, the far end goes off hook, but no audio? This may be a stupid question, but are they answering via headset, speakerphone, or handset? Do you know that you have a known good phone?

winston123 Tue, 04/01/2008 - 09:46
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yes they pickup the phone (a desk phone)no speaker or headset)and say hello, i hear them,but when I hello back to them they do not hear me.

Rick Morris Tue, 04/01/2008 - 09:48
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is this system wide or just one phone from your end?

Meaning have you tried more than one phone

winston123 Tue, 04/01/2008 - 09:54
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it is wide..have tried other phone set and other phone #'s...

How about the farend telling me they do not see I am sending rtp packets/msgs


Rick Morris Tue, 04/01/2008 - 10:04
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system wide issue, I need to think about this a little more.

can you post the telephony service config as well as the mgcp config?

winston123 Tue, 04/01/2008 - 10:16
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voice server--->2811--->switch----fw--->internet.


2811_UK-VOIP#sh run | s dial-peer

dial-peer voice 10 pots

incoming called-number .


port 0/1/0:23

dial-peer voice 100 voip

destination-pattern .

progress_ind setup enable 3

session target ipv4:x.x.x.x

dtmf-relay rtp-nte h245-signal h245-alphanumeric

codec g711ulaw

no vad



2811_UK-VOIP#sh ip ro

Gateway of last resort is 192.x.x.x to network

C 192.x.x.x/24 is directly connected, FastEthernet0/0

S* [1/0] via 192.x.x.x


no acl/no qos/cos

winston123 Tue, 04/01/2008 - 13:17
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Thanks, I was able to figure out...it was an acl applied to fa0/0 causing the issues...thx for all your help

Rick Morris Tue, 04/01/2008 - 13:18
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what did the ACL look like you had appiled?

That never crossed my mind to check.

winston123 Wed, 04/02/2008 - 11:57
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Something like this access-list 100 permit ip host 192.x.x.x(going to fa0/0)...that seemed to be dropping rtp/udp packets



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