OpenFlow, the next wave in networking

OpenFlow Logo (from www.OpenFlow.org)
OpenFlow Logo (from www.OpenFlow.org)

Read two articles recently about how OpenFlow‘s Software Defined Networking is going to take over the networking world, just like VMware and it’s brethern have taken over the server world.

Essentially, OpenFlow is a network protocol that separates the control management of a networking switch or router (control plane) from it’s data path activities (data plane).  For most current switches, control management consists of vendor supplied,  special purpose software which differs for each and every vendor and sometimes even varies  across vendor product lines.

In contrast, data path activities are fairly similar for most of today’s switches and is generally implemented in custom hardware so as to be lightening fast.

However, the main problem with today’s routers and switches is that there is no standard way to talk or even modify the control management software to modify it’s data plane activities.

OpenFlow to the rescue

OpenFlow changes all that. First it specifies a protocol or interface between a switches control plane and it’s data plane.  This allows that control plane to run on any server and still provide management for a router or switch data path activities.  By doing this OpenFlow provides Software Defined Networking (SDN).

Once OpenFlow switches and control software are in place, the SDN can better control and manage networking activity to optimize for performance, utilization or any other number of parameters.

Products are starting to come out which support OpenFlow protocols.  For example, a new OpenFlow compatible ethernet switch is available from IBM (their RackSwitch G8264 & G8264T) and HP has recently released OpenFlow software for their ethernet switches (see OpenFlow blog post).  At least some in the industry are starting to see the light.

Google implements OpenFlow

The surprising thing is that one article I read recently is about Google running an OpenFlow network on it’s data center backbone (see Wired’s Google goes with the Flow article).   In the article it discusses how a top Google scientist talked about how they implemented OpenFlow for their internal network architecture at the Open Networking Summit yesterday.

Google’s internal network connects it’s multiple data centers together to provide Google Apps and other web services.  Apparently, Google has been secretly creating/buying OpenFlow networking equipment and creating it’s own OpenFlow software. This new SDN they have constructed has given them the ability to change their internal network backbone in minutes which would have taken days, weeks or even months before. Also, OpenFlow has given Google the ability to simulate network changes ahead of time allowing them to see what potential changes will do for them.

One key metric is that Google now runs their backbone network close to 100% utilized at all times whereas before they worked hard to get it to 30-40% utilization.

Nicira revolutionizes networking

The other article I read was about a startup called Nicira out of Palo Alto, CA which is taking OpenFlow to the next level by defining a Network Virtual Platform (NVP) and Open vSwitches (OVS).

  • A NVP  is a network virtualization platform controller which consists of cluster of x86 servers running the network virtualization control software providing a RESTful web services API and defines/manages virtual networks.
  • An OVS is an Open vSwitch software designed for remote control that either runs as a complete software only service in various hypervisors or as gateway software connecting VLANs running on proprietary vendor hardware to the SDN.

OVS gateway services can be used with current generation switches/routers or be used with high performing, simple L3 switches specifically designed for OpenFlow management.

Nonetheless, with NVP and OVS deployed over your networking hardware it removes many of the limitations inherent in current networking services.  For example, Nicira network virtualization, allows the movement of application workloads across subnets while maintaining L2 adjacency, scalable multi-tenant isolation and the ability to repurpose physical infrastrucuture on demand.

By virtualizing the network, the network switching/router hardware becomes a pool of IP-switching services, available to be repurposed and/or reprogrammed at a moments notice.  Not unlike what VMware did with servers through virtualization.

Customers for Nicira include eBay, RackSpace and AT&T to name just a few.  It seems that networking virtualization is especially valuable to big web services and cloud services companies.

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Virtualization takes on another industry, this time networking and changes it forever.

We really need something like OpenFlow for storage.  Taking storage administration out of the vendor hands and placing it elsewhere.  Defining an open storage management protocol that all storage vendors would honor.

The main problem with storage virtualization today is it’s kind of like VLANs, all vendor specific.   Without, something like a standard protocol, that proscribes a storage management plane’s capabilities and a storage data plane’s capabilities we can not really have storage virtualization.