Flexibility is perhaps the key requirement of future wireless networks. It will permeate the future design of both air interface and more importantly networking technologies. The network area is a popular topic of course with the advent of Network Function Virtualization (NFV) and Software Defined Networking (SDN) but are these technologies really that new and are we exploiting them to the level we will need to in order to meet the many challenging requirements ahead of us?
I like NFV and SDN because whimsically they allow me to look really clever with academic types who think this stuff is all so new and revolutionary. To be fair in some ways it is or more precisely it could be. However, in other ways it is just a third wave in a trend that has been rolling for nearly 40 years! I cannot claim to have been in the industry at the start of this trend in the early 1980s but I spent enough years building Signaling System 7 (SS7) and Advanced Intelligent Networking (AIN) products in the 1990s to intimately understand this legacy that these new technologies are revisiting today.
It is important to understand this history well as it provides one of the few real bases for assessing where we are in this present innovation cycle and how much further we have to go before we can all pat ourselves on the back and declare that we have really made a difference.
Wave 1 of 3 started in 1982 with the breakup of the Bell system in the USA. The divestiture of the seven baby Bells spawned a wave of innovation and a genuine digital revolution in networking technologies that did change the world. The introduction of SS7/AIN was nothing less than profound in its impact. But what was it that SS7/AIN did that was so important? In a nutshell SS7 separated the switching data and control planes into a more efficient and cost effective construct for carrier bottom lines. And, AIN separated the service logic formerly co-resident with switching hardware into standalone server functions.
Sound familiar? Standards and interfaces were defined and new killer applications like 800 numbers, caller identification and voice mail were made possible. It is often forgotten but the 2G wireless era dominated by GSM that followed thereafter was fundamentally enabled by these technologies.
Wave 2 arriving in the late 1990s was defined by the brand of convergence. This convergence was of course that of the Telecoms (the SS7/AIN) and IP worlds. The emergence of soft switching provided this bridge and in essence represented a first attempt at the vision that is the NFV/SDN vision today. Soft switching was all about moving functions to servers and running everything on commodity hardware. Protocols like MGCP and later MEGACO emerged, both of which are conceptually very similar in objectives to the Openflow protocol that is generally considered as the foundation of SDN.
In my opinion, Wave 2 can only be described as a moderate success. It was never destined to be remembered as anything more. It filled a gap between paradigms and was ahead of its time. Moore’s law just wasn’t there yet to deliver the rendering of all processing intensive functions on commodity hardware. This resulted in a hybrid architecture that was neither here nor there but at the very least it did address some of the CAPEX/OPEX objectives of the day. And this brings us to Wave 3. The third wave will not be defined by NFV/SDN but rather how far we take the application of these technologies.
This third wave of networking that we are developing today was heralded by the transcendence of convergence and the crossing of the IP Rubicon in the mid noughties. There have been literally thousands of articles written about NFV/SDN and its goals and roadmap. Viewed through a historical lens the goals are basically the same as SS7/AIN some 30 years ago albeit in a true and now much larger all IP paradigm.
The roadmap of these technologies is most simply expressed in a simple understanding of the independent origins of NFV and SDN. NFV is a product of an operator driven initiative with heavy focus as would be expected on CAPEX/OPEX reduction. SDN on the other hand is a product of the research community and perhaps grander visions of actually fixing the Internet. Somewhere between these two extremes lies the true possibilities of NFV/SDN.
So what is the point of this nice retrospective? We have barely scratched the surface on what is possible with these technologies. Today’s commercial focus is CAPEX/OPEX reduction and that is certainly fair but there is so much more in the pipeline. Viewed within a historical context NFV/SDN has really delivered very little yet when compared to the impact of SS7/AIN which was indeed truly revolutionary at the time. Fully embraced NFV/SDN has the potential to be as profound. Similar to SS7/AIN it has the potential to deliver a whole new services construct. And if we are brave enough it has the potential to allow the implementation of paradigm changing visions for the Internet. If we manage all this then it is fair to say that history will be kind to us. Anything less and I am not so sure.