PBX and routing architecture
Tenants, SIP profiles, gateways, call rules, IVR, queues, recordings, failover and integrations with applications and carriers.
TELEPHONY / REAL-TIME COMMUNICATION
Telephony you can trace, fix and develop.
I design and stabilise VoIP environments, from SIP and routing to RTP, WebRTC, provisioning and carrier integrations. Every decision should be visible in the logs, measurable and reproducible.
- Scope
- SIP, PBX, SBC, WebRTC
- Engagement
- Project / migration / RCA
- Outcome
- A stable, documented service
APPROACH
From a single SIP error to the architecture of an entire platform.
Business telephony rarely stops at PBX configuration. A call is affected by endpoints, NAT, ACLs, SIP profiles, the dialplan, the carrier, codecs, media, applications and each customer's policies.
I combine signalling and RTP analysis with practical knowledge of FreeSWITCH, FusionPBX, OpenSIPS, WebRTC and SIP devices. This allows a problem to be traced from the first INVITE to the end of the session, without passing it from one team to another.
For migrations, I prepare the scope, feature mapping, test scenarios, cutover plan and rollback. For incidents, I provide the root cause, a fix and preventive actions, rather than just a temporary workaround.
AREAS OF EXPERTISE
Areas I combine in one project.
The scope follows your goal and the current state of the environment. We can start with a single issue or a complete project.
SIP and RTP diagnostics
Analysis of call flows, headers, SDP, codecs, NAT, retransmissions, packet loss, T.38, one-way audio and device behaviour.
WebRTC and media
WSS, ICE, STUN/TURN, DTLS-SRTP, RTP ranges, media relays and browser and infrastructure diagnostics.
Migrations and high availability
Inventory, feature mapping, pre-production tests, controlled cutovers, DNS/ENI failover and recovery procedures.
WHAT YOU RECEIVE
What you receive beyond the configuration.
A deployment should be verifiable, maintainable and safe to develop further.
- 01
Architecture and call-flow design, including integration points.
- 02
Configuration of the PBX environment, routing, trunks, profiles and call policies.
- 03
Test scenarios for calls, media, user features and failover.
- 04
Analysis of packet captures, logs and recordings with a clear explanation of the cause.
- 05
Deployment and rollback plans, with operational documentation for maintenance.
HOW I WORK
From context to controlled deployment.
- 01
Traffic map
I identify all parties in the call, NAT points, profiles, trunks and dependencies.
- 02
Production evidence
I collect SIP, RTP, logs, configuration and samples of successful and failed calls.
- 03
Fix and test
I make a change within a controlled scope and test edge cases.
- 04
Lasting improvement
I document the RCA, monitoring, procedures and safeguards against regression.
WHEN IT HELPS
This service makes sense when…
You do not need a finished specification. A specific problem, risk or desired outcome is enough.
- You are planning a PBX migration or consolidating multiple tenants.
- Calls work only in certain locations, networks or devices.
- WebRTC cannot establish media, or you are experiencing one-way audio.
- A carrier rejects calls because of headers, SDP or routing policies.
- You need an independent analysis of an incident, packet capture or difficult fax problem.
FreeSWITCH
FusionPBX
OpenSIPS
SIP
RTP
WebRTC
TURN
Wireshark
T.38
Docker
RELATED WORK
See how these skills come together in a working project.
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Common questions before we start.
Can you analyse an existing environment without rebuilding it?
Yes. We can start with configuration, logs and call samples. Recommendations are separated into urgent fixes, stabilisation measures and optional modernisation.
Do you also cover media and WebRTC?
Yes. The analysis can cover SIP, SDP, RTP, ICE, STUN/TURN, WSS, DTLS-SRTP, codecs, and browser and endpoint behaviour.
Can you prepare a migration plan without a long outage?
Yes. The plan covers inventory, feature mapping, a test environment, the order of tenant migrations, post-cutover validation and a rollback procedure.
What information do you need to start diagnostics?
Usually, the exact event time, Call-ID, successful and failed samples, a signalling packet capture and — where possible — RTP, platform logs and the relevant configuration excerpt are enough to begin.
NEXT STEP
Have a call problem that is difficult to reproduce?
Let's start with the evidence: event time, Call-ID, logs and a packet capture. We will identify the path, the failure point and the safest way to fix it.