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Carrier issue or CUCM 7 error

We have one long distance number that we are having issues with. If we dial it we get nothing but echo, i cant hear the person on the other end and the person on the other end can not hear me. I have tried this from several of our phones, same issue. Called from my cell phone and no problems. I talked to this person and confirmed she hears nothing but the calls are going through.

Where would I start with this issue? I know the call is going through, should i start talking to our LD carrier? or what?

We have 1 outgoing PRI.

P.S - I just tried another number with the same LD area code and got through.

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Accepted Solutions
Cisco Employee

Re: Carrier issue or CUCM 7 error

I would suggest opening a case with the telco to check if everything is good from their side.

You can take a packet capture (https://supportforums.cisco.com/docs/DOC-11735) on the phone making the test outbound call, and analyze the stream using Wireshark :


- Statistics -> RTP -> Show all streams
- Check out the IP addresses where the packets are streaming to
- Analyze -> Payload -> forward .au format

You can play the audio back and check if your voice is being sent to the MTP / gateway and if you are receiving any inbound RTP.

Also, an IOS packet capture would help narrow the problem down - http://wiki.wwjcdo.com/w/index.php5?title=Unified_Communications:Infrastructure:IOS_Packet_Capture

- Sriram

8 REPLIES
Cisco Employee

Re: Carrier issue or CUCM 7 error

I would suggest opening a case with the telco to check if everything is good from their side.

You can take a packet capture (https://supportforums.cisco.com/docs/DOC-11735) on the phone making the test outbound call, and analyze the stream using Wireshark :


- Statistics -> RTP -> Show all streams
- Check out the IP addresses where the packets are streaming to
- Analyze -> Payload -> forward .au format

You can play the audio back and check if your voice is being sent to the MTP / gateway and if you are receiving any inbound RTP.

Also, an IOS packet capture would help narrow the problem down - http://wiki.wwjcdo.com/w/index.php5?title=Unified_Communications:Infrastructure:IOS_Packet_Capture

- Sriram

New Member

Re: Carrier issue or CUCM 7 error

Wow, i would love to give this a shot............................  Hopefully I can figure it out.

Thank you.

Cisco Employee

Re: Carrier issue or CUCM 7 error

If it is to a specific number, and that call goes out the same trunk, it's likely a provider issue, since all other calls out the circuit work fine.  If you need some proof, you can open a TAC case and we can get an audio capture off the DSP at the PRI of the audio coming in the circuit.

New Member

Re: Carrier issue or CUCM 7 error

So,

i am trying to locate these option under wire shark

Statistics -> RTP -> Show all streams
- Check out the IP addresses where the packets are streaming to
- Analyze -> Payload -> forward .au format

RTP is in a different location for me.. But i got there, its under Telephony,RTP,show all streams

However when I do this I get nothing, even though i can see some skinny packets. Any ideas?  I did turn on span to port and my computer is plugged into the phone after i rebooted the phone

Cisco Employee

Re: Carrier issue or CUCM 7 error

Sometimes wireshark doesn't decode UDP headers to RTP if it can't dip in the call signaling to know that it is an RTP packet.  Find the UDP packets (there should be a bunch for the RTP audio), right click them, and say 'decode as-> RTP'.  Then do the RTP stream analysis again.

There is a preference in wireshark to automatically do this at boot, if you want to dig it up.

New Member

Re: Carrier issue or CUCM 7 error

OOO.. This is pretty cool...  It is amazing what one doesn't know !!!

Do I have to have the computer hooked up to the phone in order to sniff these packets? Can I span the switchport connected to my call manager and sniff rtp at that point? Or do I need to span the voice gateway?  Not that I will ever do this but it would be nice to know.... Man..... Knowledge is awesome isn't it ?!?!?!?!

Cisco Employee

Re: Carrier issue or CUCM 7 error

Yeah, you need to have the PC on the PC Port on the back of the phone.  Then, when 'Span to PC Port' is set for the phone, it broadcasts all the voice traffic from the SW port to the PC port.

You can always span the voice gateway and get the traffic, but the former procedure is easier.

Cisco Employee

Re: Carrier issue or CUCM 7 error

What's the version of Wireshark that you are running ?

If you type in 'rtp' in the filter field, in the packet capture, do you see packets ? You might also want to set Edit > Preferences > Protocols > RTP > Try to decode RTP outside of conversations - enable > Apply > Ok, and check again for RTP packets.

- Sriram

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