SDN Fabrics Are a New Mode of Thinking for Data Centers

At this point, it’s easy to take network virtualization for granted. The term “software-defined networking” has been a buzzword for about a decade and overlay technologies (network virtualization that doesn’t require an SDN controller) are commonplace.

SDN found its stride as a data center technology, but primarily for the east-west traffic inside a data center. What about the outside world, the networks spanning between metro regions, or countries, or continents? If virtualization is going to be the new norm for networking, it ought to apply to these longer-haul networks too?

Service providers have been eyeing those possibilities for a long time, and aggregators such as Megaport and PacketFabric have been running businesses on it. Still, it’s interesting to see data center operators take note. SDN allows for the fast, automated creation of network connections, and that could mean powerful changes for the business of interconnection. A customer could link to a public cloud on-ramp temporarily and also connect cabinets in multiple geographies as if they were in the same room.

At 451, we’ve begun referring to this as software-programmable interconnection (SPI). It includes SDN but also network overlay technologies that don’t necessarily qualify as “proper” SDN. More importantly, SPI is about those external data center connections, where a programmable fabric can turn a fleet of data centers into a single logical place, and customers’ virtual connections can be fulfilled within minutes, often via a self-service portal. The automation is what’s key, because it opens business possibilities for the data center operators.

SPI won’t appeal to all operators, but it’s already well ensconced with some of the big names. Equinix latched onto the idea early with its Equinix Cloud Exchange (ECX) fabric, which recently added trans-oceanic connectivity that lets the fabric span the globe. Digital Realty’s take on SPI is the Service Exchange, using Megaport as a connectivity partner. Colt’s “On Demand” service lets a customer build an entire virtual backbone. In an SPI sense, it can also connect a customer’s deployments in multiple Colt Data Centers.

Smaller providers can get into this game, too. In the southeastern United States, DC BLOX uses a private fiber network to connect its data centers, offering customers quick virtual cross-connects to reach services available anywhere within the fleet. Startup Vapor IO-which builds edge-computing capsules for tight quarters, such as the base of a cellular tower-has a long-term vision of connecting its sites into a SPI-like fabric. (The 4-year-old company is just getting started, with deployments in Chicago.)

Cyxtera has aggressively deployed network virtualization in its data centers, which house the former colocation business of CenturyLink. But when it comes to creating long-haul connections between metro markets, the company prefers to hand off the work to a service provider. It’s a different take on the concept, applying software automation only up to a point.

It also provokes a thought: If SPI and an Equinix-style fabric become the norm for data centers, would that tread on telcos’ turf? Maybe a little. Service providers would certainly retain some traditional roles. The enterprise branch office still has to use a telco or ISP to connect into the data center, and the long-distance fibers that make up SPI tend to be leased from an outside provider. These aren’t bad roles for the service provider to play, but it’s still true that some of the customer’s core connectivity would become the business of the data center operator. It’s interesting to muse whether there could have been (or will be) a way for service providers to play a larger role in an SPI world.