503 service Unavailable, Transcoder not Configured

[Anil Sharma]

hi Team,

I have a scenario where I have Telco device onsite connected to my Cisco Router via Gi0/1, for incoming call Telco is sending G729 codec.

I want to use transcoder and convert it to G711 so that I can use G711 codec on my LAN.

Below is my configuration:

***** Incoming Dial-peer to match call from Telco *******  

dial-peer voice 1 voip
 translation-profile incoming SIP-IN
 session protocol sipv2
 incoming called-number ^....$
 voice-class sip bind control source-interface GigabitEthernet0/1
 voice-class sip bind media source-interface GigabitEthernet0/1
 dtmf-relay rtp-nte

voice class codec 1
 codec preference 1 g711alaw
 codec preference 2 g711ulaw

***** outbound dial-peer forced to use G711 so that transcoders can get invoked *****

!
dial-peer voice 100 voip
 description *** DDI Range ***
 preference 1
 answer-address +XXT   (hiding the answer address)
 destination-pattern 123....
 session protocol sipv2
 session target ipv4:172.16.XX.XX
 voice-class codec 1
 voice-class sip bind control source-interface GigabitEthernet0/0
 voice-class sip bind media source-interface GigabitEthernet0/0
 dtmf-relay rtp-nte
 fax-relay ecm disable
 fax rate disable
 no vad
!

As I am making an inbound call my Voice gateway is sending below to Telco after receiving invite. 

Sent:
SIP/2.0 503 Service Unavailable
Via: SIP/2.0/UDP 192.168.242.46:5060;branch=z9hG4bK243F41F33
From: "XXXXXXXX " <sip:XXXXXX@192.168.242.46>;tag=50D68B4-1FEC
To: <sip:XXXX@192.168.242.45>;tag=FE7068-362
Date: Wed, 08 Feb 2017 11:40:07 GMT
Call-ID: D7B1E59B-ED2911E6-BBA2ABA8-136D0348@192.168.242.46
Timestamp: 1486553864
CSeq: 101 INVITE
Allow-Events: telephone-event
Warning: 399 192.168.242.45 "Transcoder Not Configured"
Server: Cisco-SIPGateway/IOS-15.5.3.M
Reason: Q.850;cause=47
Content-Length: 0

However transcoder is configured on my VGW and is called in MRGL/ MRG which is assigned to CUCM SIP Trunk & Phones.

dspfarm profile 2 transcode
 codec g729r8
 codec g711alaw
 codec g729ar8
 codec g711ulaw
 maximum sessions 6
 associate application SCCP

Voice gateway is not sending any invite to CUCM and in CCAPI debugs I can see disconnect 47 hence no SIP invite sent towards CUCM.

Please advise what is wrong here how can I get transcoders invoked. ?

Appreciate your inputs.

[Alexey Minaev]

Not sure but try to add codec transparent command 

[Anil Sharma]

hello Alexey,

Thanks for your response. Could you suggest where exactly should I use this codec transparent ?

[shrikant.Nadiminti1 · Accepted solution]

Hi Anil,

Solution with LTI based transcoding :

So cube receives an invite from Telco with G729 codec. Now before sending invite to CUCM cube sees that G711 codec is configured on DP pointing towards CUCM. so there is a codec mismatch and cube looks for transcoder which is registered to itself but as there is no LTI based Transcoder so call is failing. So you need to configure LTI transcoder to fix this issue.

More info about LTI based transcoding can be found in below Doc

http://www.cisco.com/c/en/us/support/docs/voice-unified-communications/unified-border-element/115018-configure-cube-lti.html

https://supportforums.cisco.com/discussion/11726586/cisco-cube-transcoding

Another way to fix it with SCCP transcoder ( I am not sure this works, theoretical answer. you may need to test it ) 

1.Configured G729 codec on dial-peer pointing towards CUCM.

2.Configure region setting b/w all end point and SIP trunk of cube to G711

cube will receive an invite from Telco with G729 codec and CUBE will send invite with G729 codec to CUCM. suppose the call should hit the DN. During codec negotiation, CUCM will see region setting b/w DN and Trunk is G711. So eventually codec b/w phone and Cube will be g711.

Regards

Shrikant

[Anil Sharma]

hi Shrikant,

Thanks for your response, I need to look into LTI based transcoding. Will do this tomorrow.

For SCCP based transcoding I had tried what you suggested however codec negotiated in this case is G729

[Anil Sharma]

hello Shrikant,

Thank you so much, it has worked for me and I am able to transcode both inbound/outbound calls.

5 star !

[shrikant.Nadiminti1]

Cheers :)

Regards

Shrikant

[tfsnchez88]

Thank you for this information.
was helpful, perform this task and now all its working well.!