Breaking down VMware's talk at the Open Networking Summit

VMware's Bruce Davie brought some fireworks to the Open Networking Summit last week with a feisty presentation, driving a wedge between the concepts of network virtualization and SDN.

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You may be wondering what all this has to do with the server access layer – here is the punchline: all the methods competing with virtual switches for controlling network services have specific contingencies in physical hardware that the virtual machine environment resides on. And if your virtual machine needs to use a piece of hardware to provide a critical service, then when that virtual machine moves, it not only needs to move to another location with the same hardware, it also requires a separate mechanism to transport the configuration for that hardware to the new location. This complicates virtual machines migrations when moving to another server whether on-premise or to the cloud … and this forms the basis by which several vendors are looking to find a new vendor lock-in strategy. When virtual machines are transported, they do not carry information with them about how the physical hardware is configured. So, if an enterprise believes a specific hardware configuration is needed, then that virtual machine can only be transported to a hybrid/public cloud partner that supports the same hardware and the proprietary mechanism used to transport the hardware configuration. The more networking services that are added to this mix, the more complex the vendor lock-in becomes. This can also be true even when using some virtualized network services so it is very important and also very possible to avoid these extensively locked-in scenarios.  The last thing that enterprises need today, especially as they move towards adopting cloud technologies, is increased vendor lock-in – it should be the opposite - increased consumer empowerment. And if awareness around this issue is not raised many enterprises could end up locked into an entire service-chain of lock in built on lock-in built on lock-in all the way up into the cloud.

A lot of what we are discussing here is fundamentally new, and correspondingly there will be proprietary methods to address newer aspects of cloud-based network service-provisioning in the near term while we are waiting for de facto and de jour standards to emerge. But just how temporary and locked-in each solution will be varies tremendously, and if enterprise consumers are smart about their approach today there is already ample information to help customers go down the right path. While this is a topic for another post, perhaps the most clear and substantive piece of guidance is to avoid hardware contingencies as much as possible, and if you have a critical need to deploy anything that is contingent on physical hardware today, work to understand the path to migrate towards a virtualized service and plan expedited migration to virtualized services as they become feasible for your environment. Microsoft and VMware are trying to move away from vendor-specific hardware requirements for their private-cloud environments, though of course these vendors private-cloud solutions will be optimized to work with their own hybrid public cloud offerings – but that does not have to mean lock-in. The key focal point here will be around the standards evolving to associate a virtual machine’s required network policy with the virtual machine container itself. And today beyond a single virtual machine’s individual networking policy, increasingly applications need to be deployed in clusters with specific network requirements for the entire cluster … and using virtualized networking is the most flexible way to prepare these applications and their required topologies and service chains for portability. The rise of OpenStack has made a substantive impact on this effort and though VMware and Microsoft are not OpenStack … industry pressure stemming from OpenStack to encourage robust compliance with OpenStack are aggressively pushing vendors in an increasingly open direction where hopefully as hybrid cloud solutions mature we will see vendor differentiation happen around toolsets and not around trying to create closed approaches to lock down virtual machine network policies and virtual network requirements.

Now with all that said, what does this mean to OpenFlow, ONS and the SDN community? My take is, it should change nothing. This is the same exact perspective that enterprises should have had a year ago, and that perspective is that network virtualization overlays are ready to go right now, and you can get started right away with whatever physical infrastructure you have in place. While I don’t question the motives of the core Nicira team, I do think many at VMware would not like a perceived need for new hardware to encumber purchases of vcloud and advanced hypervisor networking software. Putting private-cloud type architecture on traditional/legacy physical network architecture will work in most cases but it will have significant performance challenges and will limit the amount of applications that can be successfully ported into an orchestrated private-cloud environment, but that should not be a deterrent to get started with what you have today. And if you are at a stage where you can plan for a network hardware refresh, there has already been highly significant innovation in physical hardware resulting in platforms that can fully support the needs of advanced hypervisor networks today, empowering enterprises to move forward with full confidence these platforms will deliver massive value throughout their lifecycle.

The new class of network switching hardware now becoming available is built on what I call the ‘triple convergence’ combining the impact of 3 significant industry inflections. 1st, the evolution of public cloud networks was based on Clos/Spine-Leaf architecture with ECMP & L3 Multipathing. 2nd, the evolution of enterprise fabrics had been focused on distributed systems, convergence, DCB & L2 Multipathing  and then 3rd, SDN has created a significant inflection that impacts both of these earlier paradigms. These 3 areas each have significant strengths and each had been competing with the other to claim king of the hill for the future of the network. But today a relatively new class of devices has emerged that delivers the strengths and benefits of each of these paradigms. This new class of hardware is optimized for the Clos/Spine-Leaf architecture while adding support for enterprise fabric requirements and SDN. This provides the proper foundation for virtualized and cloud applications while also providing a performance and capability boost even for traditional and legacy applications. Clos architectures or enterprise-optimized Clos designs such as Dell’s Active Fabric (which I help work on in my ‘day job’) - these can provide one common data center architecture that can optimally support the triple convergence laying a foundation to optimally support cutting edge and future requirements along with the kitchen sink requirements that enterprise IT has to support today. I will go into more detail about this in a future post – and also want to note this is not a Dell commercial, many other vendors are now supporting high-density Clos-optimized platforms – the brand name that happens to be printed on the front of the box is completely secondary to the technology it supports.

This new class of hardware can optimally deliver the maximum benefits of enhanced programmability in the physical infrastructure while maximizing the benefits that can be provided by hypervisor overlay networks. The migration to advanced hypervisor networking will be very analogous to the initial deployment of server virtualization where initially only a relatively small percentage of applications were supported as VM’s and over time as technology matured support increased and now the vast majority of new applications are built to run in virtual environments. Likewise, only a subset of applications will be able to work optimally in a dynamically orchestrated elastic private cloud today, just how many apps and how much benefit will be largely contingent both on the maturity of the software and also on the maturing of the hardware to support these newer capabilities. So what is happening in OpenFlow will grow to unlock a continuing stream of value over time, but both the hardware and software available today are ready to go and can immediately start to deliver all of the most immediately relevant benefits that enterprises care about today. Everything enterprises want, need and can absorb today is ready, so my guidance would be to get an NVO strategy, get some good Clos-optimized hardware and that alone will keep enterprise IT very busy while providing massive value for years to come.

While OpenFlow and other methods to address SDN in the physical network will have a major impact, it is network overlays that pave the way for the SDN revolution in networking to take hold and have its fullest impact. And it is for this reason that attention needs to be brought, whether the means be controversial or not, the future of the evolution of SDN for enterprise data centers is contingent upon more practical deployments and advancements in virtual overlay networks. We should not be thinking about how merchant silicon should evolve to support legacy DC use cases and features; instead we should be thinking about how data center targeted silicon should be evolving in a post-NVO world … this will drive the type of cost-benefit in hardware people have hoped to see from SDN. We shouldn’t be focusing on how we can be using OpenFlow to manipulate flows to best trombone and take suboptimal network paths to inject physical appliances into east-west traffic flows; instead should be focusing on applying advanced network services inside the virtual network to take advantage of the cost, agility and portability/flexibility benefits of this approach. We should not be focusing on how enterprise applications will ‘talk’ directly to the physical network, but instead be thinking about how application requirements will be delivered to the virtual infrastructure which will then distill the application requirements into a very different type of request to the physical network as needed. This buffer space in the hypervisor network is important to limit the quantity of network change requests emanating from the applications to the physical network – the physical network needs to grow more dynamic but that doesn’t mean it will be chatting constantly with hundreds of applications as the virtual network may grow to do. This abstraction will help to bring the best combination of benefits from an increasingly dynamic, programmable fabric that still requires rock-hard stability.

Where I part way’s with Dr. Davie is around the definition of SDN. I consider advanced hypervisor networking to be part of SDN.  But I also part ways with Bethany Meyer’s description of overlays as a mere example of a SDN application. And while I appreciate ONF’s focus on preventing vendors from positioning their existing solutions as superior to a controller-based approach – I also don’t agree that SDN is only controller-based or always has to physically separate control and forwarding planes. The SDN movement would not have happened without a lot of academics & major industry players fighting to make it happen … but ultimately the SDN movement is about changing the industry primarily for the benefit of industry consumers and the advancement of the internet and the associated good it can bring to society. While we can debate where we cross the t’s and dot the i’s this does not highlight the real value of what the SDN movement is where much like the term ‘cloud’ it may be fuzzy, but from a 10,000 foot view everyone is fully aware of the revolutionary impact that the bucket of things we simply call ‘the cloud’ is having across the whole fabric of society.     

I am less concerned with what SDN is and more concerned with what it means to the people whom it benefits. SDN is about the fact that a decade ago 90% of the world’s knowledge of networking software was locked into private closed door meetings and the vast majority of people trying to innovate in networking were doing so within restricted, closed paradigms – and today we have a rapidly growing, open body of developers who are now empowered to take new approaches which will emanate from the foundation we are laying in place. The ‘cloud’ evolves at the pace which it does today only because we have opened up the underlying technologies to the eyes and minds of millions across all of society. There are no special people with special brains in this world we all have unique insights and unique value to contribute and the more that more people can be involved the more we can together innovate and bring real meaningful change. And the more people that engage in this effort the more it will be apparent that innovation is really about us, it’s about all of us, coming together and working towards a common goal. And the more of us that join in and contribute to this effort the harder it will become for a greedy rich few to steal away innovations for their own benefit.  Innovation was never about some elite people in a closed environment trying to get rich, innovation is about solving real problems that affect real people, and today our entire society is afflicted by a LOT of problems. I love computer and internet technology because of the amazingly positive impact it can have on the many ills that plague our world today. And the more this is open, the more we can rapidly innovate and rapidly disseminate knowledge and innovation so it can be applied to all those who desperately need new applications of technology to solve challenges in their own lives. The networking of computing technologies is to this century what electricity was to the last, it is a foundational technology that is changing the entire fabric of society – as Dr. Vint Cerf elegantly outlined in his excellent presentation.

SDN is nothing more than doing networking the way that it should have always been done, opening up the development paradigm and building an open source community so we can help make sure we are applying the latest technologies and so vendors cant as easily use dark corners and secrets to manipulate consumers and industries. And SDN is not any one thing, it isn’t just about enterprise campus, or data center, or SP wan, or software defined radio access networks or sensors or any one or any group of things … it is about disseminating knowledge across society to share information on how to best network things whether that be TCP/IP, Bluetooth, DWDM or anything. SDN is about the fact that just a few years ago less than 10% of the billions of microprocessors that got shipped were attached to the network and today this is changing, rapidly. That can mean a whole lot of value, a lot of jobs, careers and industries to be built and the more we open and share the knowledge the more people will be able to benefit. There is no magical Noah’s ark of legacy networking; the SDN movement is simply about bringing the best that science can offer, as openly as possible, for the benefit of society. 

Disclaimer: I am a Dell employee but thoughts and opinions shared in this blog are my own and are not necessarily those of Dell or its affilliates. 

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Copyright © 2013 IDG Communications, Inc.

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