Why should I care about software-defined networking, or SDN?
"Software defined" has become the label du jour in networking, attached to nearly everything in the data center-- including the data center itself. The fundamental idea behind the approach is that there is a separation between the decision making (or "control") function of the device or service, and its actual execution. So, in its most basic form, a software-defined network (SDN) separates the control function of how packets of data are moved, from their actual movement.
While networks themselves are built to standards and data is moved according to standard protocols, this control function traditionally resides within the network device, and its implementation is vendor-specific. Some believe that this movement of software outside the device can reduce vendor lock-in. Essentially, open source software running on servers can provide a common control capability across devices that can -- at least to some extent -- commoditize those devices.
A potentially more important reason to adopt SDN is to enhance the ability to automate and manage, through software, how packets move through an environment. Being able to programmatically control this through scripting or other software measures can ensure policy consistency across a wide range of heterogeneous devices and thus streamline operations.
While a wide range of vendors have pledged support, many details still remain to be addressed, and as with other disruptive technological processes, maturation must still occur. Right now, SDN is best suited to early technology adopters. However, as an enabler to faster, flexible and scalable provisioning and configuration, it is a concept that is quickly gaining momentum.
This was first published in July 2013