RTP / No-Audio Troubleshooting
A call can set up perfectly and still have no usable audio. Zypager separates the signalling path from the media path and follows the RTP to find where it actually stops.
Problems solved
- One-way audio
- No audio after answer
- Audio that fails only across NAT
- RTP that never starts despite 200 OK
- SRTP / DTLS negotiation failures
How Zypager helps
- Confirm the SDP each side actually agreed
- Trace RTP direction and where packets stop
- Check NAT, RTPengine and media-relay behaviour
- Validate SRTP/DTLS key exchange
Technical areas covered
Typical deliverables
- Signalling-vs-media written analysis
- Where RTP stops and why
- NAT / SDP correction steps
Frequently asked questions
Yes. One-way and no-audio problems are usually in the RTP media path or NAT/SDP handling rather than the signalling. With a SIP trace and the SDP from each leg, the media direction can be followed to the point where it stops.
Yes — Asterisk, FreeSWITCH, Kamailio, OpenSIPS and RTPengine. Many real systems combine them (edge proxy, media relay and application logic), and problems often live at the boundaries between them.
WebRTC-related work may be reviewed separately where it is directly connected to Asterisk, Kamailio, RTPengine or SIP troubleshooting, but it is not currently offered as a standard fixed-price service.
Reading traces is central to how Zypager works. A clear pcap, sngrep or Homer export, plus call details, is often enough to identify the failing transaction without live access.
Yes, on an hourly basis for urgent incidents — failed inbound/outbound calls, RTP/no-audio and carrier problems. Final scope and availability depend on access and complexity.
Related services
SIP Trunk Troubleshooting
Inbound and outbound call failures, isolated to the leg that breaks.
RTPengine Consulting
Media relay and SRTP/RTP bridging that actually carries audio.
SIP Capture / Homer
See every call. Search by Call-ID. Escalate with evidence.
Not sure which service you need?
Send the symptoms and a call example. The right starting point becomes obvious from the trace.