UCaaS platforms — Microsoft Teams Phone, Zoom Phone, RingCentral, 8x8 — all run SIP under the hood. When calls fail, quality degrades, or connectivity breaks, the root cause is almost always in the SIP signaling or RTP media. Here is how to find it.
SIPSymposium is an independent diagnostic platform not affiliated with or endorsed by Microsoft, Zoom, RingCentral, 8x8, or any other UCaaS provider mentioned in this guide.
UCaaS (Unified Communications as a Service) delivers business phone, video, messaging, and collaboration from the cloud. The major platforms — Microsoft Teams Phone, Zoom Phone, RingCentral, 8x8, Vonage Business — all use SIP as their underlying signaling protocol, whether you see it or not.
Most UCaaS deployments involve SIP in two places:
When troubleshooting UCaaS issues, identifying which leg is failing determines where to look. Endpoint registration failures are different from trunk failures, which are different from call quality issues on established calls.
| Platform | Quality Dashboard Location |
|---|---|
| Microsoft Teams | Teams Admin Center → Analytics & Reports → Call Quality Dashboard (CQD) |
| Zoom Phone | Zoom Admin Portal → Dashboard → Quality of Service |
| RingCentral | Admin Portal → Analytics → Quality of Service |
| 8x8 | 8x8 Admin Console → Analytics → Quality Dashboard |
All major UCaaS providers publish network requirements. The common targets:
| Metric | Target | Maximum |
|---|---|---|
| Latency (round trip) | < 100ms | 150ms |
| Jitter | < 30ms | 50ms |
| Packet loss | < 0.5% | 1% |
| Bandwidth per call | ~87 kbps G.711 / ~50 kbps Opus | |
When your UCaaS platform connects to the PSTN via your own SIP trunk (Teams Direct Routing, Zoom Phone BYOC, RingCentral BYOC), the SBC in the middle is where most issues occur:
The SBC access logs and SIP trace capture are your primary diagnostic tools. Most enterprise SBCs (AudioCodes, Ribbon, Oracle) have built-in packet capture and SIP trace tools.
Teams Admin Center → Users → select user → Meetings & Calls tab. Per-call quality data shows jitter, packet loss, and codec. For SIP trace on Direct Routing: capture on the SBC side — Teams itself doesn't expose raw SIP traces externally.
Zoom Admin Portal → Dashboard → Quality of Service. Per-call reports show bitrate, jitter, packet loss, latency. For BYOC/SIP issues: capture on your SBC or use Zoom's SIP trunk log in the admin portal.
Despite the cloud wrapper, UCaaS SIP failures follow the same patterns as any SIP deployment:
Upload SBC PCAP captures to SIPSymposium for automated analysis. The analyzer identifies codec mismatches, NAT issues, TLS problems, and media path failures across the UCaaS-to-carrier SIP boundary.
UCaaS (Unified Communications as a Service) delivers business phone, video, messaging, and collaboration from the cloud as a subscription service. VoIP (Voice over IP) is the underlying technology — all UCaaS platforms use VoIP/SIP internally. The difference is the delivery model: UCaaS is fully managed cloud software, while VoIP can be on-premise or cloud. Microsoft Teams Phone, Zoom Phone, and RingCentral are UCaaS platforms built on VoIP/SIP.
Check the platform quality dashboard first: Teams Admin Center Call Quality Dashboard, Zoom Admin Portal Quality of Service, or RingCentral Analytics. These show per-call jitter, packet loss, and codec data. Target jitter under 30ms, packet loss under 0.5%, and latency under 100ms round-trip. If quality is poor, run MTR from the affected endpoint to the UCaaS media server IPs to find the network hop causing the problem.
UCaaS calls to external PSTN numbers fail when the SIP trunk leg between the platform and the carrier has a problem. For Microsoft Teams Direct Routing check the SBC status in Teams Admin Center. For Zoom Phone BYOC check carrier SIP trunk registration. Common causes: TLS certificate expiry on the SBC, codec mismatch between UCaaS and carrier, number format mismatch, or firewall blocking SIP/RTP between SBC and carrier.
Capture SIP from your SBC and upload to SIPSymposium. The analyzer identifies codec mismatches, TLS failures, number normalization issues, and media path problems at the UCaaS-to-carrier boundary.