Having attended quite a few trade shows in the last six months, and having talked to numerous enterprise and communications service providers, I am left contemplating where software-defined networking is in the context of the popular Gartner hype cycle.

In case you aren’t familiar with Gartner’s hype cycle, the analyst firm charts market interest and buzz around a particular trend or technology, such as SDN, NFV, or 5G, and maps out where Gartner analysts believe the trends are: on the upswing, on the downswing, or achieving normality.

The five stages: rising, peak, sliding, climbing, and plateau are well recognized by technologists and technology marketers. In particular, high-tech vendors are very sensitive to being in the trough of disillusionment, where an over-hyped technology does not deliver on its promises, resulting in upset customers and disappointed vendors.

In its July 2018 update of the “Hype Cycle for Enterprise Networking Communications,” Gartner shows SDN climbing the slope to enlightenment. However, when I looked at the exhibits and messaging from many of the major vendors and carriers at key trade shows over the last 6 months, SDN has all but disappeared from their marketing messages. In the enterprise market, anything SDN at the edge huddles under the umbrella of SD-WAN, and from a messaging standpoint, SDN in the data center has mostly disappeared. In campus networks, well, there wasn’t much SDN there to begin with. On the mobile side, I’ve seen little mention of SDN in the core, transport, or at the edge.

Did SDN not emerge from the trough of disillusionment where it has been languishing since 2016? Or did something else happen?

I think there are a couple of reasons for SDN’s absence in marketing messages. Marketers are more sensitive to real-time market feedback and painfully aware of Gartner’s hype cycle. If I were CEO of a company and saw that one of my key technologies had been labeled as over-hyped and sliding into the trough of disillusionment, I would task my marketing department with a rebranding exercise. Why would I leave my company and its products vulnerable to unnecessary sniping and negative perception?

That’s why we have seen many SDN initiatives rebranded as SD-WAN — dynamic networking, agile networking, or cloud-native networking. Some SDN solutions are now folded under intent-based networking, while a few more are hiding out under the network automation moniker. This has led to the reduction in prominence of SDN as a key message across vendor products and the scarcity of SDN as a key message at major conferences and trade shows.

Many SDN fundamentals live on today regardless of whether we label them as such. Most modern networks exhibit key attributes of SDN, such as:

• Disaggregation of the control and data plane;
• Centralized control, which doesn’t necessarily imply a single, central controller but a policy and control logic managed from a central location;
• Programmability via standard APIs.

The other elements that are often associated with SDN include open source, merchant silicon, white boxes, and of course, the OpenFlow protocol. But these are ancillary to the core SDN principles. Some of those initiatives continue today, while others have fallen by the wayside or evolved in the way OpenFlow has become P4.

It’s not clear to me if SDN as a trend will eventually receive its due credit and reach Gartner’s plateau of productivity. This is because most of the SDN initiatives will be renamed and disguised before they reach that stage. It’s ironic that just a few years ago, vendors were falling all over each other to brand their solutions as SDN.

Regardless of how it all turns out, I think most of us in networking recognize that core SDN principles have endured and that the network has innovated as a result of the SDN movement. So, let’s give credit where it’s due and acknowledge SDN’s contribution — long live SDN.