Software Defined Networking (SDN) has evolved significantly since the concept began to be considered in the 1990s, and Martin Casado, General Partner, Andreessen Horowitz, used his keynote at the Open Networking Summit to talk about how he’s seen SDN change over the past 10 years.
As one of the co-founders of Nicira in 2007, Casado was on the leading edge of some of this SDN evolution. At Nicira, they were focused on addressing two main issues in networking. First, if you look at the industry, specific, even customer level functionality, is tied down to the hardware, and second, operations are tied down to a box. As computer scientists, they assumed that these problems could be solved by creating high-level abstractions and using a modern development environment to reduce the complexity of implementing network systems; however, they quickly learned that networking is not computing. Networking, Casado says, is less about computation and more about distributed state management. This led Nicira down the path of creating a distributed SDN operating system based on the idea that a general platform would simplify the distribution model for application developers. They came to realize that it wasn’t quite this easy.
First, networking isn’t a single problem; different parts of the network have different problems. Second, it can be hard to reduce complexity in the platform when applications need to be able to manage this complexity in order to scale. The biggest change happening in the industry around this time in late 2008 and early 2009 was the idea of using a vSwitch as an access layer to the network for implementation of network functionality, and this proved to be a successful idea.
They also had the idea of creating a domain specific language that would help reduce some of the complexity; however, the downside was that they were never quite clear that they were able to get full coverage of the existing model, and by changing the abstractions, they were creating a massive learning curve and breaking existing tool chains. The turning point was when they decided that the abstractions themselves could be networks with logical networks sitting on top of a network virtualization layer / hypervisor that acts as the interface to the physical network.
All of this work led Casado to four key lessons:
- Put product before platform.
- Virtualize before changing abstractions.
- Software over hardware.
- Sales / Go to market are as important as technology
Watch the video of Casado’s entire talk to learn more about what he’s learned about the evolution of SDN over the past 10 years.
Interested in open source SDN? The “Software Defined Networking Fundamentals” training course from The Linux Foundation provides system and network administrators and engineers with the skills to maintain an SDN deployment in a virtual networking environment. Download the sample chapter today!
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