We are experiencing intermittent call drops when transitioning from an Architect IVR flow to a live agent using our BYOC trunk (AudioCodes Mediant 8000). The issue occurs specifically when the IVR attempts to transfer the call to the agent’s softphone.
Environment:
- Genesys Cloud: Release 2312
- SBC: AudioCodes Mediant 8000, Firmware 7.3.2
- Trunk Type: BYOC SIP
- Encryption: SRTP (AES-128)
Symptoms:
- Call enters IVR via PSTN → SBC → Genesys Edge.
- IVR plays prompts successfully.
- On transfer to agent, Genes Cloud sends a REFER request to the SBC.
- SBC responds with
488 Not Acceptable Here. - Call disconnects immediately.
Logs:
The SBC logs indicate the SDP attribute in the REFER request lacks the correct crypto line for SRTP renegotiation. However, our trunk configuration in Genesys Cloud has “Use SRTP” enabled globally.
Attempted Fixes:
- Verified SBC supports RFC 3261 REFER.
- Checked SBC logs: The initial INVITE has correct SRTP attributes. The REFER seems to strip them.
- Tested with a direct SIP trunk (non-BYOC) and the transfer works, isolating the issue to the BYOC path.
Is there a specific Architect setting or SBC header manipulation required to preserve SRTP context during REFER requests in this version? We noticed a similar issue in older forums related to early media handling, but our flow does not use early media.