Like many network professionals, I feel the need to navigate through the frontal tide of confusion, and grasp the essence of change. Initially, as I swallowed a lot of information, I was easily confused and swayed one way or another. Let’s face it, most materials out there are vendor affiliated, which is inherently partial and biased. But over time, a clearer picture has emerged. However pure and simple, it has given me consistency and continuation in the thought process. I hope it will help you establish your own framework as well, and chart your own course forward.
Virtual Networking – the beginning of change
Let’s start with why, why the change, why now. To me, change is not about doing what networking already does, in a different way. Fundamentally, networking enables communication and supports compute, which enables applications. Compute has gone through its own revolution which is virtualization. Compute virtualization brought networking into the hypervisor environment, thus creating an overlap between two previously separate domains. This rudimentary form of virtual networking can be seen in the form of current generation virtual switches.
In the current generation architecture, virtual switches mainly serve to provide virtual ports for VMs, while most of the feature and security remain with the physical network. The advancement in compute virtualization has put more demand on networking, more segmentation to support multi-tenancy and security, more agility to support provisioning in minutes rather than days, requirements that hardware based networking and security simply cannot keep up with. The catalyst of change is virtualization.
The Rise of Software Defined Networking
In the legacy model, virtualization is still closely coupled with network hardware. For traditional networking to be more agile, it needs to be “programmable”. Earlier OpenFlow architecture was proposed to be just that, but in reality hardware replacement was a non-starter. The Nicira model took a different approach. Rather than pushing programmability on hardware, it decouples virtualization from traditional networking. A new form of virtual networking emerges around the hypervisor, mostly in the form of software. With emerging technology such as VXLAN, the virtual “edge” effectively becomes the new access layer, where much of the complexity such as segmentation as well as future services will reside. Traditional networking can be greatly simplified.
Thus the overlap between compute and networking has grown into a new layer. It has also become clear that this new layer on the edge is optimally positioned to deliver services such as load balancing, firewall and NAT.
· Decoupling of virtual from physical. With new technology such as VXLAN, SDN provides an overlay network model which is mostly independent of the physical network. Decoupling makes it possible to instantiate VXLAN and deliver much of the cloud services without changing configurations on physical switches
· Central decision making. The controller has full knowledge of the virtualized networks. Its cloud level view is ideal for managing resources centrally.
Just as networking exists to serve applications, SDN emerges to support data center optimized for the cloud. In parallel with advancement in virtual switches (DVS, 1000v, Open vSwitch), a new class of cloud management system (vCloud, OpenStack) is emerging. In order for SDN to be successful, it must be an integral part of the Software Defined Data Center, supporting service/platform/application packaging, rapid provisioning, and automated service deployment.
Virtual networking is the new playground. The lines between network and virtualization vendors have blurred, as well as those between network and compute domains. There is a new domain emerging. I call it puzzle solving at the data center level, putting all the pieces together, compute, network, storage, security, making them fit seamlessly.
Networking’s growth area is with virtualization, in software. In this emerging field, networking no longer runs on dedicated hardware and ASIC. At the host level, it shares processing with compute. At the data center level, the distributed architecture becomes more centralized, with the controller becoming the new “supervisor”.
To remain competitive in a hybrid cloud environment, organizations need to move forward to take advantage of the power and features of Software Defined Networking. IT architects need to unify network, virtualization and software at the cloud level. I’ll brainstorm some concrete steps a network engineer can take in an upcoming post.