Maybe the two SIP devices do not have compatible codecs so they are going through an MTP to comply with the audio capabilities? You should try and check SDP message exchange between the two using RTMT Traces.
Also make sure that within the SIP Profile the flag "Media Termination Point Required" is not checked.
The MTP is most probably being alocated due to a DTMF mismatch. The third party SIP phone is using Inband DTMF but an H.323 gateway can only to Out of band DTMF with the CUCM. Thus we need an MTP to achieve this.
SIP traces provide key information in troubleshooting SIP Trunks, SIP
endpoints and other SIP related issues. Even though these traces are in
clear text, these texts can be gibberish unless you understand fully
what they mean. This document attempts to br...
Please find the attached HTML document, download and open it on your PC.
This provides an easy to use form where you simply answer a few
questions and it will render the proper jabber-config.xml file for you
to copy/paste. There is built in logic to verif...
CUCM Database Replication is an area in which Cisco customers and
partners have asked for more in-depth training in being able to properly
assess a replication problem and potentially resolve an issue without
involving TAC. This document discusses the bas...