Symptom
DTMF payload interworking fails.
DTMF flow through the 2 MTP sessions but always using the original payload type.
Conditions
ISR4K Router working as MTP and CUCM invoking 2 MTP sessions for the same call in the same media resource (MTP instance)
Further Problem Description
SCCP MTP on ISR4K does not Interwork payload on RFC2833 DTMF if multiple sessions are used
Call Agent---SIP (RFC2833 payload 127) ---CUCM Server---SIP (RFC2833 payload 101)---Call Agent
If CUCM invokes 2 MTP sessions on the same Media Resource payload conversion does not work.
In this scenario, DTMF is received with payload 101 and is sent on the other leg as 101 instead of 127.
SCCP instructions from CUCM are as they should.
If only one MTP session is used everything works fine.
This issue is only seen in ISR4K platforms, works fine in ISRG2 Platforms.
