Protocol & Infrastructure
SIP Development Services
SIP looks simple on the wiki page — INVITE, 180, 200, ACK — and gets interesting when you have to interop with 15 carriers, each of whom interprets RFC 3261 slightly differently. We work at the protocol layer: debugging one-way audio with Wireshark, patching SIP stacks to handle non-compliant peers, writing B2BUAs that negotiate codec differences between legs, and building SIP-aware middleware that sits in front of PBXs to normalize what carriers send. Whether you're building a softphone, an SBC, or a SIP-based SaaS, we've debugged the problem you're about to hit.
Who it's for
- Teams building custom SIP clients or servers where off-the-shelf won't fit
- Operators interop-testing with new carriers and hitting SIP compliance issues
- Platforms needing header manipulation, SIP trunk bonding, or call forking
- Anyone chasing a one-way audio bug that's been open for three weeks
Our approach
- 1Start every investigation with a pcap — SIP bugs lie in the wire, not in logs
- 2Use SIPp for reproduction and regression — if we can't script the failure, we don't understand it yet
- 3Prefer patching upstream stacks (PJSIP, sofia-sip, reSIProcate) over forking
- 4Document every carrier quirk so your ops team doesn't hit it twice
- 5Pair protocol-layer fixes with monitoring so the next regression is visible
What you get
Wireshark-verified root-cause analysis for protocol-level bugs
SIPp scenarios reproducing issues and validating fixes
Custom B2BUA or middleware where existing tools don't fit
Carrier interop matrix documenting every quirk we've characterized
Patched SIP stack builds (PJSIP, sofia-sip) with changes submitted upstream
Monitoring that catches regression at the SIP layer, not just at service-level metrics
Common questions
Related services
Session Border Controller Solutions
Open-source and commercial SBC deployments with topology hiding, DoS protection, and media handling.
Kamailio Development
Dispatcher tuning, SIP routing logic, and Kamailio-as-SBC deployments for carrier platforms.
VoIP Consulting
Architecture reviews, vendor evaluations, and on-call expert access for teams running voice infrastructure.
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