User makes external call but cancel the call getting no answer. If the user cancel the call, CUCM v10.5 sends sip CANCEL to the telephony provider. But this CANCEL does not contains Reason Header with cause code.
I may be misunderstanding this but if you are making an external call I assume the call is using a SIP Gateway which is where the the Cancel Q850 Cause Code 16 would generate from. Is there an issue when the user is hanging up an external call attempt?
Yes, the issue is when the user is hanging up an external call attempt. CUBE is used as SIP gateway. But the CUBE is just translating the CANCEL which it receive from CUCM.
Of course I can configure CUBE to add the Reason sip-header via sip profile. But if CUCM will send CANCEL with Reason header in another call situation then CUBE will add the second Reason sip-header Q850 Cause Code 16. The CANCEL will consist two Reason headers in this case. Am I right?