I have cross a very strange issue and symptoms describe below:
PSTN caller intermittent (2%-3% of total 300 calls per day) experienced one-way audio when call answer by UCCX agent where agent cannot hear PSTN caller but PSTN caller can hear agent. Then agent end the call but PSTN caller remain active and the call returns to the queue and answered by next available agent with 2-way audio fine. When one-way audio issue happen, the same call always been re-queued without disconnecting and will be answer by next agent with no issue.
We are running 2 CM cluster and has inter-cluster SIP trunk setup between 2 CM cluster running v10.5 and v11.0 and the UCCX is on v11.0 as well. The call flows as below:
ITSP -- sip --> CUBE -- sip --> CM v10.5 -- inter-cluster sip trunk --> CTI RP on CM v11.0 -----> UCCX v11.0 --- cti port ---> agent on CM v11.0
Has anyone cross this strange issue and can share resolution?
Carriage investigated this issue but claimed that they could not find problematic call we mentioned and customer advised to close this incident without chasing further due to issue no longer reproduceable.
The only workaround we found (UCCX 11 / Jabber client) for the same issue was putting a call on hold and retrieving it back. Only then does the 2 way audio start working again without problems.
Have a Cisco TAC case open for this so would appreciate if someone has a solution already.
One way audio problems are 99% of the time routing issues between the phones and the ITSP
Having said that, there's also a 1% chance that the UCCX setup you have in place is not supported (i.e. you may be surprised by the unexpected behavior when this this is the case.. please go through the unsupported checklists at your earliest https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cust_contact/contact_center/crs/express_11_6/release/guide/uccx_b_release-notes-for-uccx-116/uccx_b_release-notes-for-uccx-116_chapter_01.html)
- Midcall changes/SIP updates to the calls' codecs can cause this. Check if transcoding issues are present when this happens.
- If using Jabber as a soft client, try to stop any video parameters from passing through to the ITSP, those can cause unexpected problems.
- Reproduce the issue and capture some logs.