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New Member

Forward Problem

I have a big problem with IP Phone when I configure forward for it.

On CUCM , I configure one IP phone with Noanswer External forwarding to a mobile.

When I Call from PSTN to this IP Phone but no ones answer , it is going to forward the call to my mobile. My mobile ring but the call is "one side calling " ( one phone was ringing but one another can heard what you say on the phone which was ringing )

I try to change CUCM but, It not work .

Please help me to solve this problem

Thank you.

Cisco Employee

Re: Forward Problem

What type of PSTN circuit are you going out?  It would be beneficial to get debugs off that circuit during the issue.

I'm hacing a hard time understanding the symptom too.  It is unclear to me who hears ringing/ringback, and who hears the voice.  Is it the calling or called party?


Cisco Employee

Re: Forward Problem

Hi Duc,

Your problem is not very clear, are you able to pick up the forwarded call on your mobile phone? and not hearing the audio? or you have a problem with ringback tone?

Please clerify and also provide some info about the topology that you have such as H.323 or MGCP gateway etc.



New Member

Re: Forward Problem

I use E1 port on voice gateway

I use mobile A call to IP Phone and IP Phone forward to mobile B. Mobile B ring event if mobile A pick up. Mobile A can hear noises form Mobile B.

This fault happen only with IP phone forward no answer external, otherwhile IP phone forward all and others types of forward works normally.

This is a part of my gateway configure

Cisco Employee

Re: Forward Problem

First, you're missing an inbound voip dial-peer.  Add this, at the minimum:

dial-peer voice 1 voip

no vad

dtmf-relay h245-alpha

After that, get these debugs:

debug isdn q931

debug voip ccapi inout

debug h225 asn1

debug h245 asn1

Collect debugs via:

Router(config)# service sequence
Router(config)# service timestamps debug datetime msec
Router(config)# logging buffered 10000000 7
Router(config)# no logging con
Router(config)# no logging mon
Router(config)# voice iec syslog

Router# term len 0

Router# sh logg

Your nonstandard PI config under the POTS dial-peer may be the culprit for your ringback, but debugs should shed more light on that.  Are the PI commands in there for another specific issue with ringback?


New Member

Re: Forward Problem

My config is complex with many dialpeer

OK, I will send you all

Cisco Employee

Re: Forward Problem

See what the output of that debug shows, then.

New Member

Re: Forward Problem

OK, Wait for me until the weekend please.

I will show you my debug dialpeer and debug isdn q931.


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