In 2006 Cisco orchestrated a massive change in their business – and their logo. At the time they said that the logo change was in line with their stated aim of becoming a software company, and I think most of us thought this was utter madness – after all, Cisco was a hardware company and how on earth were they going to make routers, switches, and firewalls out of the software?
But in 2008 a collaboration between Stanford University and UC Berkeley delivered the OpenFlow protocol which defined a programmable network protocol that could help manage and direct traffic among routers and switches no matter which vendor made the underlying router or switch. This was the birth of SDN – Software Defined Networking.
Fast forward to 2021 and SDN is no longer a thing of myth, magic, and imagination, it is a living, breathing, (machine) learning, (artificially) intelligent “thing”. You no longer need a physical switch or router in order to set up a network. But if you do like shiny new boxes alongside cutting-edge technology, then you can still have both, giving you a self-learning, self-healing, and to a degree self-securing, network. Which you control with code rather than with cables.
Remember that the traditional function of the network function was to connect users and branches or campuses to applications hosted on servers, typically in the data centre – which was based at HQ. Companies invested heavily in dedicated circuits to ensure secure and reliable connectivity. The days when the office network was faster and more stable than your internet connection at home!
This network followed the traditional OSI model, as per below
As more and more applications are being moved to the cloud, it becomes blatantly obvious that a WAN made of dedicated links, all going in one direction – back to HQ, needs transforming. Why not just use the internet as an extension of your WAN? But, opening the WAN up to the internet creates nightmares for network engineers who now need to balance user experience and security over an inherently insecure and unstable platform.
SD networking is an overlay architecture that helps to overcome the biggest drawbacks of the traditional network. It builds secure, unified connectivity that is carrier-and transport-agnostic. Think of it as the OSI model turned on its head, like this:
The application layer is now driving network innovation and network engineers need to learn a new language – one which software developers already know. It’s a language rich in APIs and SDKs. And it’s a language that you can no longer ignore.
So, don’t ask why you should learn SD networking, start asking if you can afford not to.