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CUCM 8.X with Avaya 5.2.1 Integration

Hi All,

I am trying to integrate CUCM with the Avaya PBX that is runnin on the below server and gateway.

Server :s8720

Gateway :G650.

I am not familiar with the Avaya system ,but we are trying to integrate it with CUCM 8.6 using the H323 trunk.I used the below link to setup the trunk and I am having issues with calls going from CUCM to Avaya.  (This document uses CUCM 4.X has as an example and this is what I could find in Cisco's Website)

At the same time calls from Avaya to CUCM works fine.Just wanted to know if anyone here has ran into this issue and looking for inputs to resolve it.

Thanks in advance,


Chris Deren
Hall of Fame Master

I used docs from this portal for Avaya H323 integration between various versions of CUCM and things worked out OK:

Is the call making it to Avaya or failing at CUCM side? What are you hearing?



Hi Chris,

Thanks for the link.

The call is failing in the CUCM side and not reaching Avaya.When I looked into the RTMT logs, the CUCM is sending a "Service Unavailable" to the IP Phone.I hear a busy tone on the phone.



Well, that is not necessarily an indication of failure on CUCM. I would suggest the following:

  1. use Dialed Number Analyzer on CUCM see if the call is suppose to work
  2. Perform a trace on Avaya to see if it hits it
  3. Look at CUCM traces for disconnect cause.


Hi Chris,

1.When I use the DNA the call is sent to the right RG which has the h323 gateway that is configured for this Integration.The call flow seems to be correct.

2.We did enable the trace on the Avaya and did not see the call hiting it.

3.When I looked the CUCM traces, that is where I get the Service Unavailable with cause code 503.


Cause code 503 would indicate SIP error, is this SIP or H323 trunk?


Its a h323 trunk ,but the IP phone that am using a SIP phone.



Then the error you are looking at is between CUCM and phone, you need to investigate the cause code between CUCM and Avaya in the H323 H.225 setup messages.

What is the H323 GW in CUCM pointing to? Is it the CLAN IP address? is the CLAN confiuration on Avaya pointing to the same IP address?  Is the GW and RL configuired to route on all Nodes?


The H323 GW in CUCM is pointing to the CLAN IP address.I think the CLAN configuration on Avaya is pointing to the same IP address.I will double check and confirm.

This this Scenario what is the traces/logs that am supposed to look in the CUCM ?



Hi Chris,

I just verified and confirmed the CLAN on the Avaya is pointing to the same IP address that am using on my H323 gateway.

Moreover as I mentioned earlier the calls are working from Avaya to CUCM.




Make sure that the Avaya is seeing an attempt for the call to come across "List trace TAC".  "TAC" being the Trunk access code for the H323.

Also make sure the Avaya can handle the digits being sent "Display incoming call handling treatment" as this will need to be set as they would a carrier ISDN etc....

The important one is the Avaya trace to see if there is an attempt though.



As I mentioned earlier , we enabled the trace on the AVAYA side and dint see any hits when a call is made from a CUCM phone to Avaya Phone.




Hi Simah,
I have an Avaya and Cisco network where I am interconnecting Avaya CM5.2.1 to CUCM 8.5. I have found that I prefer SIP to make these interconnects because there is less to configure on the Avaya this way. When I configure the Avaya, I first "add signaling-group xx", Group Type "SIP", I set the transport method to "TCP", Near-End Node Name (CLAN or PROCR), Far-End Node Name (CUCM-Sub or Pub), Far-end Network Region (which is the network region locally going out to far end) and Direct IP-IP Audio "y". The rest of the Trunk group setup is done like the H.323 trunk. You will need to have an entry for the station in Pub-Unknown for the Caller ID to work.

I have 46 Avaya Nodes all interconnecting to CUCM in various flavors of Avaya CM from 3.x to 6.2. The CM3/4 nodes are H.323 and CM5/6 are SIP. SIP is a much better transport for Trunks between ACM and CUCM.

Joe Broderick
I changed the IP-IP audio to "y" to allow IP phone (Avaya) to IP phone (Cisco) direct audio communication.

Sent from Cisco Technical Support iPad App


Maybe your problem is with ""trunk group for channel selection" , you need put in that field the same number of the trunk group number. I was faced the same issue and after put the number in the field , working fine for me.

Just solved my issue with above tip. Many thanks Marcelo. Avaya <-> CME

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