06-03-2015 12:59 PM - edited 03-17-2019 03:13 AM
Hi all,
I have a customer with CUCM 10.5(1) solution. He uses a SIP Trunk for PSTN calls. CUCM is integrated to the PSTN in the following manner.
CUCM === CUBE === ITSP. The ITSP is using EO only so I have to check the "MTP Required" in the Trunk configuration on CUCM. I know that CUCM can do EO without MTP but I could not use it because I can't get supplementary services to work with it.
My problem is the following : after reaching a certain number of calls (around 40), CUCM starts sending SIP invites without SDP which causes calls to fail. I don't think it is a problem with MTP shortage because a have the SIP Trunk's MRGL including an IOS software MTP with 500 sessions plus two MTP of CUCM IPVMS.
What could the issue be? please advise?
Best Regards