What is SDN?
Early Adopters Define Sofware-Defined Networking
February 04, 2016

Shamus McGillicuddy
EMA

Share this

Greg Ferro recently blogged about how attempts to define software-defined networking (SDN) are a waste of time. He wrote: "You can’t define 'Software Defined Network' because it's not a thing. It's not a single thing or even a few things. It's combination of many things including intangibles. Stop trying to define it. Just deploy it."

To a great extent I agree with him. It’s hard to define SDN as one thing, given that it is applied to so many different areas of networking: Data centers, enterprise campus, the WAN, radio access networks, etc. And each vendor that introduces an SDN product to the market is working from a definition that fits into its own strategy. Cisco’s is hardware-centric. VMware’s is software-centric, and so on.

So, yes. Just deploy it. But … what do those people who deploy SDN have to say?

EMA did offer a definition of SDN in its recently published research report Managing Tomorrow’s Networks: The Impacts of SDN and Network Virtualization on Network Management. The research is based on a survey of 150 enterprises that have deployed SDN in production or have plans to do so within 12 months. The report explores the benefits and challenges of SDN. Much of the research explores the readiness of incumbent network management tools to support SDN infrastructure and it identifies new functional requirements for these management tools.

(Side note: We also surveyed 76 communications service providers on the same topics, but I’m limiting this blog discussion to enterprise networking).

Since we were surveying people who were actually implementing SDN, we thought it would be valuable to get their take on what SDN actually is. We asked them the following question: When thinking about the definition of SDN, what characteristics of an SDN solution are important to you? Here are the top three defining characteristics of SDN for early enterprise adopters:

■ Centralized controller (39% of respondents)

■ Fluid network architecture (27%)

■ Low-cost hardware (25%)

A decoupled control plane and data plane (13%) was tied with intent-based networking as the least important defining aspect of SDN solutions.

These top three responses from early adopters of SDN present a pretty simple definition of the technology. And when you think about it, these terms align what we’re seeing in the market place. Nearly every SDN solution has a centralized controller, or at least a centrally accessible, distributed controller. This controller serves as a single point of control, access, programmability and data collection for the network. Most solutions also offer low-cost hardware, or — in the case of overlays — require no new hardware.

Fluid network architecture, I would argue, gets to the heart of what SDN is all about. It enables networks that are flexible and responsive to changes in infrastructure conditions and business requirements. This contrasts sharply with static, highly manual legacy networks, where any change to network connectivity in a data center or a remote site can require days, weeks or even months to implement. SDN’s promise is a network that can respond to change quickly and fluidly, thanks to increased programmability, for instance.

Therefore, I defer to the wisdom of early adopters when trying to come with up a definition. SDN is characterized by a fluid network architecture that is enabled by a centralized controller and low-cost hardware.

One final point on the subject of defining SDN. We asked early adopters of software-defined WAN (SD-WAN) a similar but distinct question on the defining characteristics of SD-WAN, which EMA considers sufficiently different from other varieties of SDN to warrant its own definition. In the case of SD-WAN, cloud-based network and security services were the number one defining aspect of such solutions. Centralized control was the number two priority, followed by hybrid WAN connectivity.

Shamus McGillicuddy is Senior Analyst, Network Management at Enterprise Management Associates (EMA).

Shamus McGillicuddy is Research Director for the Network Management Practice at Enterprise Management Associates (EMA)
Share this

The Latest

January 18, 2022

As part of APMdigest's list of 2022 predictions, industry experts offer thoughtful, insightful, and often controversial predictions on how Network Performance Management (NPM) and related technologies will evolve and impact business in 2022 ...

January 13, 2022

Gartner highlighted 6 trends that infrastructure and operations (I&O) leaders must start preparing for in the next 12-18 months ...

January 11, 2022

Technology is now foundational to financial companies' operations with many institutions relying on tech to deliver critical services. As a result, uptime is essential to customer satisfaction and company success, and systems must be subject to continuous monitoring. But modern IT architectures are disparate, complex and interconnected, and the data is too voluminous for the human mind to handle. Enter AIOps ...

January 11, 2022

Having a variety of tools to choose from creates challenges in telemetry data collection. Organizations find themselves managing multiple libraries for logging, metrics, and traces, with each vendor having its own APIs, SDKs, agents, and collectors. An open source, community-driven approach to observability will gain steam in 2022 to remove unnecessary complications by tapping into the latest advancements in observability practice ...

January 10, 2022

These are the trends that will set up your engineers and developers to deliver amazing software that powers amazing digital experiences that fuel your organization's growth in 2022 — and beyond ...

January 06, 2022

In a world where digital services have become a critical part of how we go about our daily lives, the risk of undergoing an outage has become even more significant. Outages can range in severity and impact companies of every size — while outages from larger companies in the social media space or a cloud provider tend to receive a lot of coverage, application downtime from even the most targeted companies can disrupt users' personal and business operations ...

January 05, 2022

Move fast and break things: A phrase that has been a rallying cry for many SREs and DevOps practitioners. After all, these teams are charged with delivering rapid and unceasing innovation to wow customers and keep pace with competitors. But today's society doesn't tolerate broken things (aka downtime). So, what if you can move fast and not break things? Or at least, move fast and rapidly identify or even predict broken things? It's high time to rethink the old rallying cry, and with AI and observability working in tandem, it's possible ...

January 04, 2022

AIOps is still relatively new compared to existing technologies such as enterprise data warehouses, and early on many AIOps projects suffered hiccups, the aftereffects of which are still felt today. That's why, for some IT Ops teams and leaders, the prospect of transforming their IT operations using AIOps is a cause for concern ...

December 16, 2021

This year is the first time APMdigest is posting a separate list of Remote Work Predictions. Due to the drastic changes in the way we work and do business since the COVID pandemic started, and how significantly these changes have impacted IT operations, APMdigest asked industry experts — from analysts and consultants to users and the top vendors — how they think the work from home (WFH) revolution will evolve into 2022, with a special focus on IT operations and performance. Here are some very interesting and insightful predictions that may change what you think about the future of work and IT ...

December 15, 2021

Industry experts offer thoughtful, insightful, and often controversial predictions on how APM, AIOps, Observability, OpenTelemetry, and related technologies will evolve and impact business in 2022. Part 6 covers the user experience ...