All Your SDN Are Belong to Us

One of the frustrations of SDN has always been the fact that if you ask six different people for a definition of SDN, you’ll get ten different answers, at least. This stems in part from the usual IT buzzword symptoms. When a system is used for competitive advantage, each company wants to define its own brand of […]


NSX – The Saga Continues

I’ve written before about the difficulty as a user of getting hold of VMware’s NSX and about other problems with the release, but a small recap is in order. Founded in 2007, Nicira was bought by VMware in 2012 for its SDN platform. This consists of deep integration that combines the open VXLAN standard with vSphere’s vShield-like products […]

Pokémon Go!

I woke up one morning last week to find my wife capturing a Squirtle in the corner of the room. Not the real room, of course: just the augmented reality version that exists in Pokémon Go. The idea of augmented reality, of using computers to superimpose extra information relevant to the real world, has existed […]


Many of these posts talk about network functions virtualization (NFV) rather than software-defined networking (SDN). NFV is a subset of SDN that is more specific, and it is applicable to a higher level of the application stack. Whereas SDN is aimed at the network layers, NFV is aimed at manipulating the data. The idea of […]

On Enterprises and Service Providers

“Service provider” and “enterprise” are often seen as opposites in networking circles. (For the purposes of this article, “enterprise” means “business” rather than “large business.”) I’m fortunate to have worked closely with both service providers and enterprises. The contrast is indeed sharp. Service provider networks are the product to be sold; they need to be fast, responsive, […]

Hyperconvergence and OS

In the good old days (rose-tinted spectacles required), there was only one operating system in the stack. It took care of device drivers and file IO. There were many flavours of OS, depending on the period, from UNIX and Windows to OS/2 and MacOS, and many, many others. Over time, the selection of operating systems in the data center reduced […]

From Mainframes to Containers

A few days ago, Stevie Chambers tweeted about the evolution from mainframe to container: “Why is it a surprise that VMs will decline as things miniaturise? Mainframes → Intel → VMs → Containers, etc. Normal, I’d say.” By “Intel” here, I’m going to take Stevie to mean “rackmount servers.” I’m also going to assume that by […]