PSTN Incoming Calls cannot be transfered to IP Phones

Unanswered Question
Nov 5th, 2007

Hi,

I do have a Cisco 2650XM with 2 E1s, one for incoming and the other for outgoing calls towards PSTN.

When I receive a phone call from the PSTN that reaches the Attendant Console Pilot Number, the Operator can talk with the caller. Once the Operator set the HOLD key on the IP Phone, 1st) there is no MOH stream towards the PSTN, and if the operator would like to UNHOLD the phone call, there is silence on both sides. when I see the codec displayed on the IP Phone, it is g.729.

Please help me to understand if this is a mismatch codec issue or something related to rounting?

I am using CCM 4.1.3

Thanks in advance for your Help

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nomiel Tue, 11/06/2007 - 00:07

Hello.

Have you G.729 in Supported MOH Codecs in Cisco Ip Voice Media Streaming App Service Parameter?

allan.thomas Tue, 11/06/2007 - 01:21

I'm a little surprised the codec is G729 in the first instance. Is the voice gateway in the same geographic location as the Attendant Console?

If this is the case then I would expect G711, and the fact that it is not would suggest that your regions have been configured incorreclty on both endpoints?

Please check the configuration for Gateway and Attendant Console? Incidentally is the voice-gateway MGCP or H323.

If the attendant console is indeed in a different location and region as expected, then do you provide MoH from the IOS gateway?

Regards

Allan.

jberthin Tue, 11/06/2007 - 06:21

Hi Allan.

Thanks for your mail.

I believe I am blocked with many ideas going on my mind. maybe you can clarify this simple concept to me, and I apologize for taking some or your precious time.

voice gateway is in the same location as CCM.

but any phone call that I attempt to place, either to internal network, or also to the PSTN, I am working with g.729. By default the ip phones will use that codec, do I am right?

when any PSTN phone call gets in, and the operator tries to make the transfer. after pressing the hold, or straigth the transfer option, there is complete silence, with the phone call still being placed, and no voice. but if in any of the sides press the tone keypad, all the tones are heared on any side.

just the tones, but not the voice.

thanks again for your help.

Javier

jberthin Tue, 11/06/2007 - 06:30

Hi Allan

Conferences are accomplished within the ip tel network.

but as I said before, pstn incoming calls, as soon they are set on hold, or attempted to be transfered, at the new end side, there is complete silence.

Thanks again

Javier

allan.thomas Tue, 11/06/2007 - 07:29

Ordinarily I would expect to see G711 within the same location, and essentially all devices should be assigned to the same Region. The fact the call is established using G729 suggest a problem within your Regions.

IP Phones endpoints are capable of negotiating between G711 and G729 codecs therefore avoiding the necessity for transcoding.

Verify that your gateway and IP Phones are using the same Region. You may have multiple devices pools so check the DevicePool assigned to the gateway and the IP phones?

Do you have more than one region? If you do, check that the within region for where the Gatways and IP Phones for Attendant Console are located is set to G711 and that to remote regions is G729, if configured of course.

Incidentally what protocol is used on the voice-gateways, MGCP or H323?

The fact that you hear silence when on hold and not Tone-on-Hold suggest that CallManager has completed the handshaking with the Gateway. If this was not the case then CCM would default to Tone-on-Hold.

Due to the PSTN caller on hold hearing silence, then problem could be attributed to the IOS configuration or network.

If CCM has failed to provide the gateway with MoH, the I would expect to hear ToH, and this would due CCM not having an MoH resource available. This could be because the required codec has not been enabled on Cisco CallManager (check the media streaming service parameters and verfiy which codecs are supported, by default all of them are selected).

Another reason could be because no MRGL has been assigned to the gateway, or if one has been assigned, then it has insufficient resources.

Please can you forward a copy of your gateway configuration, and also post screen shots of the device pools and regions so that I could sanity check them.

Regards

Allan.

jberthin Wed, 11/07/2007 - 08:55

HI Allan

I am enclosing the configuration for the gateway towards PSTN, it has 2 E1s circuits, one for inbound, and the other for outbound calls. This gtwy has also a TCL file, that sounds a greetings asking for the extension number in order to route the external call straight to the extension (this works fine, but not all the clients know the extensions.)

we have fixed the region problem, so now CBBA region with its CCM 4.1.3 has ag.711 codec, and through the WAN codec is g.729.

the BIG PROBLEM now is that any PSTN incoming call, reachs the operator, and asks for an extension. The operator press hold or transfer and at that time, there is no MOH stream, and when the final extension is reached, both callers just hear silence.

I am enclosing also a configuration related to a transcoder that is configured in another router.

Thanks again for all your help Allan, I appreciate it very much.

Javier

allan.thomas Wed, 11/07/2007 - 09:59

From the screen shot of the gateway configuration within CCM you do not have MTP required as checked.

Do you experience the same problem with the attendant console with other IP Phone endpoints when transfering external calls?

H.323 gateway does not have the capabilities by itself to put calls on hold or transfer.

You will require a Media Termination Point to implement such features that H.323 does not support (such as hold and transfer), and you will need to check the MTP check box on the gateway.

Regards

Allan

jberthin Wed, 11/07/2007 - 13:44

Hi Allan

I believe you are right, however should I consider to get some Hardware MTP configuration?

Thanks again for your help.

Javier

jberthin Tue, 11/06/2007 - 06:24

Thanks for your mail.

I believe I am blocked with many ideas going on my mind. maybe you can clarify this simple concept to me, and I apologize for taking some or your precious time.

voice gateway is in the same location as CCM.

but any phone call that I attempt to place, either to internal network, or also to the PSTN, I am working with g.729. By default the ip phones will use that codec, do I am right?

when any PSTN phone call gets in, and the operator tries to make the transfer. after pressing the hold, or straigth the transfer option, there is complete silence, with the phone call still being placed, and no voice. but if in any of the sides press the tone keypad, all the tones are heared on any side.

just the tones, but not the voice.

thanks again for your help.

Javier

allan.thomas Thu, 11/08/2007 - 08:43

Currently you have transcoding configured on the second gateway you could possibly assign this to the MRGL which is assigned to the device-pool for the Attendant Console?

I'm not sure whether I have mentioned this in a previous post, but also noticed that you do not have a voice class codec applied to your voip dial-peers?

Regards

Allan.

guiter.carpio Fri, 07/03/2009 - 12:04

A little question, its possible to have 2 E1 both for inbound and outbound and controlled by using one tcl script ???

Explain :

E1 : 1234567

E1 : 9876543

bpth number must be sent to the same extension 312.

this is possible with a tcl application ?

guiter.carpio Fri, 07/03/2009 - 12:34

ok i understand, with one tcl i can manage both lines, what sentence or command did i need to use for this ???

this is the output of my gateway

application

service AA flash:its-CISCO.2.0.1.0.tcl

paramspace english language en

paramspace english index 1

param operator 7000

paramspace english location flash:

paramspace english prefix en

param aa-pilot 1234567

!

can i use another

param operator 6000

param aa-pilot 9876543

in the same application ???

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