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Okay, I've been thinking about this a lot recently but I think I may be more confused now than I was originally when I started. I can't find anything about Openflow that helps me understand what it is. None of the websites I have found have given a solid definition of what Openflow really is and what it does, at least if they do I can't comprehend it. Is there an easy way to explain this standard so my small brain can understand it?

I understand that Openflow is a way to abstract networking away from switches and can be managed from software, etc etc. I feel like it might be a little easier to grasp if I had exmaples of application. But so far searching has failed me. What is Openflow? How can it help me? What does it offer?

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closed as not constructive by Tom O'Connor, EEAA, Khaled, Sven, Wesley Apr 18 '12 at 5:49

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its an attempt to push out cisco from the datacenter, look at the pica8 switches as one of many examples of openflow compatibile devices that are quite cheap. – tony roth Apr 15 '12 at 17:42
HP is pushing Openflow as well, that's sort of the reason I started looking into it. I just wanted some clarification on the capabilities and the possible uses. – jmreicha Apr 16 '12 at 13:35
It will be interesting to see how this pans out for the smallish datacenters. – tony roth Apr 16 '12 at 15:47

First, you need to be familiar with the concept of "Software Defined Networking." The short story is that SDN decouples the "control plane" from the "forwarding plane." The control plane is the part that creates network logic ("Where do these packets go? How are they routed and why?"). The forwarding plane is the hardware that actually moves electrical impulses around (aka the bits).

The software that handles the control plane will, ostensibly, run on commodity servers. The hardware that handles the forwarding plane can be separate from the control plane systems. Even if both planes are on the same hardware, they still need to communicate to eachother since, after all, they've been logically (if not physically) separated.

Openflow is the bit of software that bridges the gap between the control plane and the forwarding plane.

For more information, I suggest searching the topic out on Greg Ferro's site, Ivan Pepelnjak's site and the Packet Pusher's site. To be sure, it is a large topic that takes much familiarity with networking history and the present state of networking theory.

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