There's a quiet revolution in networking underway. It's all about software defined networking, usually abbreviated SDN, which abstracts the networking hardware in an infrastructure and separates the so-called "control plane" (the part of networking that decides where data must flow, and at what priority or service levels) from the "data plane" (data forwarding instructions on a per-packet basis). While this may not sound like much of an insight, or even slightly revolutionary, it's reworking the way people understand how networks behave and operate.
SDN makes it easier to get at and work with abstract networking relationships.
SDN is an outgrowth of two intertwined phenomena:
1. Virtualization (which applies as much to network components and infrastructure elements as it does to servers and desktops)
2. Cloud-based computing (which makes virtual networks, infrastructures, platforms, and applications all easy to consume through the pay-as-you "aaS" ["as a Service"] model).
And in fact, SDN makes certain aspects of networking easier to abstract, quantify, visualize and manage, including identification of transmission destinations (which have to be able to move around arbitrarily in a virtualized/cloud-based environment), logical groupings, access controls, quality of service (QoS) designations and enforcement/application, and network flows. Because all of these things are quite important in modern networks, this adds compelling power and value to SDN tools and technologies. It also helps explain why SDN is catching on in such a big way.
Here's some "Recommended Reading" on SDN, to help you find your way into this fascinating subject matter:
1. Wikipedia "Software Defined Networking"
2. Compsci 514 (Duke University) "Software Defined Networking" (PowerPoint Presentation, 32 slides)
3. Cisco White Paper "Software Defined Networking: Why We Like It and How We Are Building On It" (PDF)
4. Vishal Shukla: "Introduction to SDN - OpenFlow & VxLAN" (book & e-book, Amazon link)
5. Rajesh K. Sundararajan: "SDN - A Definitive Guide" (e-book only, Amazon link)
6. Dr. Nick Feamster (Georgia Institute of Technology; free course) "Software Defined Networking"
There's lots of material out there, so if you want more, search for "SDN tutorial," "SDN introduction," or other variations on that theme. Enjoy!