Antipatterns is a name given, most notably in computer science, to bad, suboptimal or unsuccessful ways of doing things that have been repeatedly observed in the wild--observed so much that they need to be named and taught. Twenty years of building carrier-grade VoIP service delivery systems of varying size and sophistication, and using open-source components, will give one quite a lot of perspective on what that looks like in the telecom/RTC industry.
In this undeniably opinionated talk, I will go through my top examples, honed through painful experience, of software engineering and architectural follies you should avoid when building a SIP trunking or multi-tenant PBX softswitch platform.