The concept of software-defined networking (SDN) has generated considerable interest during the last several months. Although SDNs can be realized in more than one way, the OpenFlow protocol seems to have drawn a critical mass of prospective customers (mainly cloud-service providers with vast data centers) and solicitous vendors.
If you aren’t up to speed with the basics of software-defined networking and OpenFlow, I suggest you visit the Open Networking Foundation (ONF) and OpenFlow websites to familiarize yourself the underlying ideas. Others have written some excellent articles on the technology, its perceived value, and its potential implications.
In a recent piece he wrote originally for GigaOm, Kyle Forster of Big Switch Networks offers this concise definition:
“At its most basic level, OpenFlow is a protocol for server software (a “controller”) to send instructions to OpenFlow-enabled switches, where these instructions give direct control over how those switches forward traffic through the network.
I think of OpenFlow like an x86 instruction set for the network – it’s low-level, but it’s very powerful. Continuing that analogy, if you read the x86 instruction set for the first time, you might walk away thinking it could be useful if you need to build a fancy calculator, but using it to build Linux, Apache, Microsoft Word or World of Warcraft wouldn’t exactly be obvious. Ditto for OpenFlow. It isn’t the protocol that is interesting by itself, but rather all of the layers of software that are starting to emerge on top of it, similar to the emergence of operating systems, development environments, middleware and applications on top of x86.”
Increased Network Functionality, Lower Network Operating Costs
The Open Networking Foundation’s charter summarizes its objectives and the value proposition that advocates of SDN and OpenFlow believe they can deliver:
“The Open Networking Foundation is a nonprofit organization dedicated to promoting a new approach to networking called Software-Defined Networking (SDN). SDN allows owners and operators of networks to control and manage their networks to best serve their users’ needs. ONF’s first priority is to develop and use the OpenFlow protocol. Through simplified hardware and network management, OpenFlow seeks to increase network functionality while lowering the cost associated with operating networks.”
That last part is the key to understanding the composition of ONF’s board of directors, which includes Deutsche Telecom, Facebook, Google, Microsoft, Verizon, and Yahoo. All of these companies are major cloud-service providers with multiple, sizable data centers. (Yes, Microsoft also is a cloud-technology purveyor, but what it has in common with the other board members is its status as a cloud-service provider that owns and runs data centers.)
Underneath the board of directors are member companies. Most of these are vendors seeking to serve the needs of the ONF board members and similar cloud-service providers that share their business objective: boosting network functionality while reducing the costs associated with network operations.
Who’s Who of Networking
Among the vendor members are a veritable who’s who of the networking industry: Cisco, HP, Juniper, Brocade, Dell/Force10, IBM, Huawei, Nokia Siemens Networks, Riverbed, Extreme, and others. Also members, not surprisingly, are virtualization vendors such as VMware and Citrix, as well as the aforementioned Microsoft. There’s a smattering of SDN/OpenFlow startups, too, such as Big Switch Networks and Nicira Networks.
Of course, membership does not necessarily entail avid participation. Some vendors, including Cisco, likley would not be thrilled at any near-term prospect of OpenFlow’s widespread market adoption. Cisco would be pleased to see the networking status quo persist for as long as possible, and its involvement in ONF probably is more that of vigilant observer than of fervent proponent. In fact, many vendors are taking a wait-and-see approach to OpenFlow. Some members, including Force10, are bearish and have suggested that the protocol is a long way from delivering the maturity and scalability that would satisfy enterprise customers.
Vendors Not In Charge
Still, the board members are steering the ONF ship, not the vendors. Regardless of when OpenFlow or something like it comes of age, the rise of software-defined networking seems inevitable. Servers and storage gear have been virtualized and have become more application-driven, but networks haven’t changed much in the last several years. They’re faster, yes, but they’re still provisioned in the traditional manner, configured rather than programmed. That takes time, consumes resources, and costs money.
Major cloud-service providers, such as those on the ONF board, want network infrastructure to become more elastic, flexible, and dynamic. Vendors will have to respond accordingly, whether with OpenFlow or with some other approach that delivers similar operational outcomes and business benefits.
I’ll be following these developments closely, watching to see how the business concerns of the cloud providers and the business interests of the networking-vendor community ultimately reconcile.