Dear community,
I recentely faced an issue where DTMF didn't work while trying to involve anTRP in the following call flow:
Jabber --srtp--TRP --srtp--- CUCM Conference now IP IVR
I've made some tests and I came to the conclusion that TRP is not able to decrypt properly DTMF SRTP events.
Jabber ----srtp------ CUCM IP IVR works fine
Jabber ----rtp---TRP---rtp--- CUCM IP IVR works fine
Jabber ----srtp---TRP---srtp--- CUCM IP IVR doesn't work
TRP is forced on jabber side only.
DTMF debug on ISR4K shows irelevant RTP-NET DMTV Events (138, 183, 234, ....)
Since the destination is DTMF OOB only, TRP must decrypt the SRTP DTMF Events in order to notify them through SCCP.
I was unable to find any document stating if MTP/TRP supports SRTP DTMF decryption.
Thanks for your help