Daily Archives: July 17, 2012

Debate Over Openness of Open vSwitch

Late last week, the illustrious Ivan Pepelnjak pointed me to a post by Matthew Palmer at SDN Central. Pepelnjak thought the post would interest me, and he was right.

While I encourage you to read Palmer’s post firsthand, I will summarize it briefly. Basically, Palmer makes a two-part argument and then leaves us with unsettled questions. The first part of his argument is that the virtual switch (vSwitch) has become the “prime real-estate for network virtualization within the datacenter.” As such, the vSwitch has become a strategic battleground for vendors and service providers alike.

This brings us to the second part of Palmer’s argument, which is more controversial. Palmer implies that the first part of his argument, about the valuable real-estate inhabited by the vSwitch, wouldn’t be a major point of contention if a genuine and viable open vSwitch — and not just an open-source vSwitch — were available. Alas, he says, that is not the case.

Open . . . or Just Open Source? 

Palmer suggests that Open vSwitch (OVS), which wears the mantle of open-source vSwitch, is a proprietary wolf in sheep’s clothing.  He says Open vSwitch might be open source, but that it is far from open. Instead, he says, it is under the direction of one company, Nicira Networks, which “controls the features, capabilities, and protocols supported within OVS and when they are released.”

Writes Palmer:

“Since OVS is ‘Open’ Nicira will gladly take your free labor to develop on OVS and give you an Apache license to ‘fork’ your own distribution; but they essentially decide which features and protocols, from what contributors will be included in the mainline distribution at what time.  This basically masquerades OVS as the ‘free’ switch in a freemium business model where the vendor locks you in with their better, proprietary, paid for version.  This is why many others in the networking community are looking for alternatives to invest their time and development resources. “

From Naive Newcomer to Proprietary Villain

My first reaction was that Nicira must be making some headway commercially. I don’t think I’ve ever seen a vendor go from virtual-networking upstart to proprietary villain in a shorter period of time. Palmer is an accomplished business-development executive, and he corresponds regularly with a large circle of industry notables. Clearly, Nicira has gotten their attention.

Not long ago, many denizens of that same community dismissed Nicira as a bunch of technically brilliant but commercially ingenuous SDN neophytes who weren’t a serious threat to the networking industry’s status quo. If Palmer’s post is an accurate barometer of industry sentiment, that view has undergone significant revision.

In some ways, Palmer’s post was foreshadowed by a commentary from Dell’s Brad Hedlund earlier this year. Whereas Palmer bemoaned the proprietary stranglehold that Nicira might gain over the Open Networking Foundation (ONF) and large swathes of the SDN community, though, Hedlund took a different tack. While he, like Palmer, noted that Nicira’s engineers played a defining role in developing Open vSwitch, Hedlund was more interested in how Nicira’s approach to SDN prefigured a “significant shift .  . .  when it comes to the relevance and role of “protocols” in building next generation virtual data center networks.”

Diverse Project

In light of Palmer’s charges, I thought I’d reach out to Nicira to solicit a reply. Fortunately, Martin Casado, Nicira’s CTO, was kind enough to get back to me with what he termed “off-the-cuff comments” on Palmer’s post.

His first point was that “Nicira doesn’t have a proprietary vSwitch (never has).” In his post, Palmer wrote that Nicira “has their own proprietary version of Open vSwitch . . . . “

Casado also noted that “Nicira’s kernel module is in mainline Linux, which is clearly not controlled by Nicira,” and that “OVS is one of the largest and most diverse open source projects in the world,” with a “profile better and broader than most projects.”

The Nicira CTO also wrote that Open vSwitch is used by “potentially competitive companies,” including Cisco, Big Switch Networks, NEC, and Midokura. Casado wrote that these vendors are “welcome to fork it, or do whatever they want with it.” On that point, he and Palmer appear to be in agreement, though Palmer contends that Nicira essentially controls the direction of OVS.

SDN’s Long, Hot Summer

Finally, though Palmer’s post suggested that Nicira’s could undermine OpenFlow by swapping it out for a “proprietary (i.e. non-OpenFlow) protocol that only works with Nicira’s vSwitch and controller,” Casado responded as follows: “Development of OpenFlow 1.1 – 1.3 is moving ahead at an extremely aggressive pace.  Multiple organizations are working on it (NTT, Google, T-Systems, and Nicira), and much of the implementation is done and has been committed.”

That response, in and of itself, does not close the door on Nicira leveraging another protocol — and we know that Nicira has proposed two variants of OpenFlow, one at the edge and one in the core, to support an MPLS-like SDN fabric — but it also suggests that OpenFlow isn’t in any imminent danger of being sidelined or relegated to oblivion.

Still, Palmer’s post raises compelling questions and demonstrates that, in the summer of 2012, SDN is generating heat as well as light.


Infrastructure Virtualization Versus Converged Infrastructure

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.

Network’s Turn

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.