SPEA MS Teams Diagnosis, Troubleshooting and Rectification
Challenge
Capstar Solutions engaged in addressing an issues of choppy audio and delays during call setup in the customer’s IVR system before it reaches Microsoft Teams users. The customerbemploys Microsoft Teams Direct Routing with a PRI that is connected to Cisco voice gateway.
Calls are currently forwarded to a Cisco Unity Connection (CUC) IVR before reaching a Session Border Controller (SBC) for Teams delivery.
Capstar Solutions engaged in addressing an issues of choppy audio and delays during call setup in the customer’s IVR system before it reaches Microsoft Teams users. The customerbemploys Microsoft Teams Direct Routing with a PRI that is connected to Cisco voice gateway.
Calls are currently forwarded to a Cisco Unity Connection (CUC) IVR before reaching a Session Border Controller (SBC) for Teams delivery.
Solution
OBSERVATIONS
- Choppy audio and jitter specifically on IVR-assisted calls; direct/Teams-to-Team and extension-to-extension calls are working fine.
- Perceptible post‑IVR delay (DTMF collection/transfer adds seconds before ringing a user or queue).
- Potential codec/transcoding hops introduced by CUC (e.g., G.711 ↔ G.729/SILK)increase latency and packetization mismatch.
- Additional SIP signalling hairpin (PRI Gateway → CUC → SBC) increases call setup time and failure modes.
- CUC resource constraints (CPU/DSP/media resources/jitter buffers) possible under load.
- Limited observability for end‑to‑end quality (CUC lacks Teams-native analytics/CQD correlation).
- Operational complexity (maintaining a single-feature Cisco component solely for IVR).
ROOT CAUSES
Given that issues are isolated to the IVR path, the most probable contributors are:
- Transcoding or packetization mismatch on the CUC leg.
- Media anchoring at CUC is causing non‑optimal media paths versus Teams media
bypass. - DTMF relay and re‑INVITE handling at CUC introduces call setup lag.
- Resource contention on CUC (e.g., during peaks) elevates jitter/latency.
Solution
Removing of Cisco Unity Connection and route inbound PSTN directly to Microsoft Teams Auto Attendant/Call Queue via SBC.
- PRI Gateway → SBC → Microsoft Teams (AA/Queues/Users)
- Enable Teams Media Bypass where applicable to shorten RTP paths to clients.
- Standardize on low‑transcoding architecture (G.711 on PSTN leg; SILK/Opus on Teams leg handled natively by Teams). The SBC should avoid unnecessary codec interworking.
- Utilize Teams Auto Attendant for IVR, schedules, language, and key presses (DTMF).
- Integrate Compliance Recording (if required) with certified solutions via Direct Routing.
OBSERVATIONS
- Choppy audio and jitter specifically on IVR-assisted calls; direct/Teams-to-Team and extension-to-extension calls are working fine.
- Perceptible post‑IVR delay (DTMF collection/transfer adds seconds before ringing a user or queue).
- Potential codec/transcoding hops introduced by CUC (e.g., G.711 ↔ G.729/SILK)increase latency and packetization mismatch.
- Additional SIP signalling hairpin (PRI Gateway → CUC → SBC) increases call setup time and failure modes.
- CUC resource constraints (CPU/DSP/media resources/jitter buffers) possible under load.
- Limited observability for end‑to‑end quality (CUC lacks Teams-native analytics/CQD correlation).
- Operational complexity (maintaining a single-feature Cisco component solely for IVR).
ROOT CAUSES
Given that issues are isolated to the IVR path, the most probable contributors are:
- Transcoding or packetization mismatch on the CUC leg.
- Media anchoring at CUC is causing non‑optimal media paths versus Teams media
bypass. - DTMF relay and re‑INVITE handling at CUC introduces call setup lag.
- Resource contention on CUC (e.g., during peaks) elevates jitter/latency.
Solution
Removing of Cisco Unity Connection and route inbound PSTN directly to Microsoft Teams Auto Attendant/Call Queue via SBC.
- PRI Gateway → SBC → Microsoft Teams (AA/Queues/Users)
- Enable Teams Media Bypass where applicable to shorten RTP paths to clients.
- Standardize on low‑transcoding architecture (G.711 on PSTN leg; SILK/Opus on Teams leg handled natively by Teams). The SBC should avoid unnecessary codec interworking.
- Utilize Teams Auto Attendant for IVR, schedules, language, and key presses (DTMF).
- Integrate Compliance Recording (if required) with certified solutions via Direct Routing.
Results
CUC IVR is the bottleneck - Direct and extension-to-extension
internal calls that bypass above mediums do not face issues of delaying receipt of voice. By retiring the Cisco Unity Connection and any unused Cisco Unified Communications Manager components. Instead, direct calls from the PRI gateway
route to the SBC and then to the Microsoft Teams Auto Attendant and Call Queues. This simplification enhanced call quality, removes unnecessary delays, and enables better support
and compliance.
CUC IVR is the bottleneck - Direct and extension-to-extension
internal calls that bypass above mediums do not face issues of delaying receipt of voice. By retiring the Cisco Unity Connection and any unused Cisco Unified Communications Manager components. Instead, direct calls from the PRI gateway
route to the SBC and then to the Microsoft Teams Auto Attendant and Call Queues. This simplification enhanced call quality, removes unnecessary delays, and enables better support
and compliance.