VoIP service provider anti-patterns | Evariste Systems Blog

In the software business realm, the term anti-pattern refers to dysfunctional but commonplace solutions to technical and business problems. Anti-patterns occur widely enough that one can reasonably generalise about them — that’s why they’re "patterns".

There are many acknowledged technical anti-patterns in the software engineering world, such as database-as-an-IPC, or, my personal favourite (hat tip to The Daily WTF), the Inner-Platform Effect. The latter will be easily recognisable to a programmer who has been asked to write an application with business rules and data objects that can be extensively customised by non-programmers; invariably, the customisability demands made upon such systems approach infinity, ensuring that, over time, working with the system comes to resemble programming (if not necessarily "coding") in its cognitive and technical dimensions, and therefore to require a skill set that approximates that of a programmer. Not only does this fail to address the original demand of the businesspeople–reduce dependence on programmers–but now there is a poorly performing, half-baked system-within-a-system. Such a system has all of the downsides without any of the benefits. Yet, it happens all the time where people who don’t really understand how software works are in charge. If you work with many organisations, you’ll come to encounter some manifestation of it over and over. That’s what makes it a prime example of an anti-pattern.

It’s hard to meaningfully identify anti-patterns in new industries or fields of commercial endeavour. The VoIP ITSP is a relatively recent development, all things considered. Companies in immature industries whose business models and equilibria still unsettled tend to try lots of different ways to make money, as well as to package and productise what they do in different shapes and sizes. Failed experiments–even repeated failures–in new growth markets aren’t necessarily anti-patterns. A lot of praxis, industry consolidation, and market development has to happen before something can truly be deemed an anti-pattern.

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I would go further than most to say that anti-patterns aren’t just ideas that have repeatedly seen failure over a significant stretch of time, but in fact are consistently bad ideas or misconceptions that, for one reason or another, retain a stubborn hold on the imagination of businesspeople and managers even in the face of accumulated common knowledge that they are bad. My preferred term for such ill-fated ventures is "worst practices". By now, the VoIP ITSP (Internet Telephony Service Provider) industry has been around long enough, and I have worked with so many ITSPs that I can safely venture to typify some of these "worst practices" from my 12 years of consulting experience, growing up with this industry.

Not all of them can be identified and avoided, of course, and I certainly don’t plan to try to survey them all in one meagre article. But some of the more conspicuous ones are worth stepping through in the hope that it will help someone starved of quality advisors avoid bad technical and business decisions. I must also be candid about the limitations of my perspective; my experience is primarily (though not exclusively) with US-based small to medium ITSPs and telcos, and heavily weighted toward open source VoIP solutions, so some of what I say may be unavoidably tendentious from a strictly enterprise or profoundly foreign-market perspective. Caveat emptor.

#1: SBC metaphysics

The Session Border Controller (SBC) industry has come to have an indelible hold on the conceptual vocabulary in which VoIP-related plans are laid. I have spoken this in a previous article on the suitability of Kamailio as an SBC and elaborated upon the problems it poses in my Kamailio World 2019 talk in Berlin ("Kamailio as an SBC: definitive answers"), so I won’t belabour it here very much.

What bears remark here is that there are a lot of ways to engineer the core, the customer access layer, and the intra-industrial carrier interface of VoIP networks, and conventional SBCs from the big...