GSM to G711ulaw transcoding on IP to IP Gateway.

[ShailendraK]

Hi All,

I have a 3745 configurad as an IP to IP gateway. I have a SIP trunk with G711ulaw to a Call Manager(5). There is another SIP trunk with GSM codec configured to another device. I can see that the transcoding does not kick in between G711 and GSM codec. For testing sake I tried to configure G729 to the second device and it works fine but not with GSM.

Does anybody have any suggestions/experience/information on this? Please let me know if you need more information aboout the configuration etc.

Thanks in advance for the help.

Shad

[Nicholas Matthews]

Hi Shad,

I think the feature you're looking for is called 'Universal Transcoding'.

Check out this doc:

http://www.cisco.com/en/US/docs/ios/12_4t/12_4t15/it_unitr.html

The configuration is a little bit different than normal transcoding.

hth,

nick

[ShailendraK]

Hi Nick,

Thanks for the reply. This is exactly how I have configured the Gateway. Again just to recap it works between G711ulaw and G729 for example but not G711ulaw and GSMFR or GSMEFR. Any suggestions?

Regards

Shad

[Nicholas Matthews]

Hi Shad,

Which IOS version are you on?

What codecs do you have enabled under the transcoder profile?

-nick

[Nicholas Matthews]

Hi Shad,

Do you also have the same voice-class codec on all of your dial peers? This is a restriction of CUBE currently that both the incoming and outgoing dial peer must have the same voice class codec.

As well - you're not using GSM AMR are you? This codec is only supported on the 5X00 boxes with additional licensing.

-nick

[ShailendraK]

Hi Nick,

I could not get back to you on the weekend.

The IOS version I have tried are:

1. c3845-ipvoice_ivs-mz.123-11.YZ2.bin

2. c3845-entservices-mz.124-22.T.bin

I have different codecs on the dial-peers dial-peers. I have G711ulaw on one(to-from the CUCM 5) and GSMFR and GSMEFR on the other. The box I am using is 3845. I have all the above mentioned codecs configured under the Transcoder Profile. Please let me know if you want to have a look at the configurations and I will include an attachment.

Thanks again Nick.

Shad

[paolo bevilacqua]

12.3(11)YZ2 is too old for universal transcoding.

12.4(22)T1 would be OK, but you selected a non-IVS image.

Get the correct IOS image and try again.

[ShailendraK]

Hi,

Thank you for the reply.

Hope you do not mind my next question. Unfortunately I have to ask because I could not find any information on cisco.com.

Will you be able to tell if version 12.4.20-YA2(ED) would support the IP to IP transcoding? The reason I ask is because I only have 256 DRAM and 64 Flash. The versions highre than 12.4.20-YA2(ED)require 512 DRAM and 128 Flash for ivs image.

Thank you once again in advance.

Regards

Shad

[paolo bevilacqua]

I would use ipvoice_ivs. Note you mentioned 12.3 YA and not 12.4 YA in your previous message.

[Nicholas Matthews]

Hi Shad,

I would make sure I'm on the IVS image, even though the commands exist on other images. It's supposed to be an IPIPGW-only feature.

When you say you have different codecs - are they hard set on the dial peers, or are they in a codec class?

If they are in a codec class it will not work unless the two codec classes are the same.

-nick

[ShailendraK]

Hi guys,

Thank you very much for your help. I have tried all the recomendations made by you. The codec I need is GSM full-rate(gsmfr on the IOS). I seem to see it only in 12.3 IOS and the not the recent 12.4 versions. With this IOS(12.3), the transcoding is working between a TDM to IP call. It does not work between any IP to IP call.

Any more suggestions to make it work are welcome. Thanks again.

Shad