While writing about software-defined networking (SDN) and what it makes possible, I have been thinking about how its essential premise, and the premise behind infrastructure virtualization, conflicts with visions of converged infrastructure promulgated by the leading systems vendors in the information-technology (IT) industry.
According to the Wikipedia definition, converged infrastructure encompasses servers, storage, networking gear, and software for IT infrastructure management, automation, and orchestration. Accordingly, converged infrastructure leverages pooled IT resources to facilitate automated resource provisioning in support of dynamic application workloads.
Hardware Pedigrees in Software World
Leading vendors, most with more hardware than software pedigrees, have sought to offer proprietary converged-infrastructure offerings that closely integrate the hardware elements with software-based management attributes. In this regard, we can cite vendors such as Cisco (with a storage assist from EMC or NetApp), Hewlett-Packard, Dell, Hitachi Data Systems, Oracle (though networking remains on open question there), and, perhaps to a lesser extent, IBM.
Now, let’s think about SDN and where it ultimately leads. Cisco would like us to believe that SDN, if it leads anywhere, will eventually take us to network programmability, with a heavy emphasis on the significance of a northbound API (or APIs). Cisco says that the means — in this case, SDN — are not as important as the desired ends, networking programmability, and many of Cisco’s enterprise customers will doubtless agree.
SDN End Games
Another SDN outcome is network virtualization, which admittedly can also be achieved through other means. But an interesting aspect of SDN’s approach to network virtualization, with its decoupling of the network’s control and data planes, is that it results in the abstracting of software-based network intelligence from the underlying hardware-based network brawn. It’s a software paradigm taken to a logical extreme, with server-based software running at the network edge controlling an abstracted pool of no-frills networking hardware.
Indeed, this is one end game for SDN, first playing out in the data centers of the major cloud service providers that guide the affairs of the Open Networking Foundation (ONF), and then — at some indeterminate future point too difficult to forecast without a Ouija board and a bottle of scotch — also at large enterprises worldwide.
Let’s elaborate further. SDN facilitates network virtualization, which in turn is harnessed and orchestrated by cloud-management software, which also manages virtualized compute and storage infrastructure. As we’ve seen already in the compute world of servers, it’s getting increasingly difficult for a vanity hardware vendor to earn a buck in a virtualized world. Many service providers have found that they can get boxes that satisfy their needs, at lower prices, directly from ODMs that often build servers for name-brand OEMs. Storage is being virtualized, too.
And now it is the network’s turn.
In such a world, how much longer will it make sense for customers to achieve converged infrastructure from single-source vendors that equip their hardware with proprietary fripperies and hooks to facilitate lock-in? Again, we can see these trend playing out at large service providers. Some have begun buying their networking hardware off the rack from ODMs, saving not only on capital expenditures (certainly the case for servers), but also on operating expenses relating to the ongoing management of network infrastructure. It’s true that they’re trading one sort of complexity for another, pushing it up the stack and into software rather than an operational hardware, but it’s a trade-off they’re clearly willing to make, probably because they have the resources and skill sets to make it work (and pay).
Obviously that is not a recipe for everybody, certainly not for most enterprises today. But times are changing, and it isn’t inconceivable to foresee a day when the enterprise will be able to avail itself of third-party private-cloud software and management tools that will allow it to exploit a similar model of virtualized infrastructure.
Prescience Pays Off
In the big picture, as far as the established networking vendors are concerned, the ONF’s conception of SDN is about more than just OpenFlow, and even about more than network programmability. It’s about how SDN supports a model of network virtualization, in service to infrastructure virtualization, that significantly enfeebles hardware-based business models. Some of these hardware-oriented vendors will not successfully pivot to a model of virtualized infrastructure and software primacy.
On the other hand, some vendors have had the prescience to see this trend approaching on the horizon; they understand its inevitability, and they have positioned themselves better than others to survive, and perhaps even thrive, after the eventual market transition.
We’ll look at one of those vendors in a subsequent post.