Don’t have a clue about SDN?

Aptly named, the Software Defined Networking Controller is the “brains” of the operation. This device sits at the top of your SDN hierarchy. This device is critical for your applications to communicate with the physical routers and switches that makeup your network.

The SDN Controller possesses a “global” view of the entire network. It knows about all of the nodes, the best paths between them, and the other potential paths. Amazingly, the SND Controller can failover to alternate paths even faster than the fastest converging of routing protocols. Perhaps this is not fair since the SDN Controller does have to worry about notifying other devices and computing best paths.

Are there various controller options for the various SDN solutions out there? You bet there are! For example:

• Cisco Systems – the Cisco Application Policy Infrastructure Controller (APIC)
• Hewlett Packard – the HP Virtual Application Networks (VAN) SDN Controller
• NEC – the NEC ProgrammableFlow PF6800 Controller
• VMware  – the VMware NSX Controller
• OpenDaylight – the OpenDaylight open source SDN controller
• OpenContrail – the OpenContrail SDN controller
• Many, many more!

Notice that you will have choices between commercial and an open source controller. Today we find that most operational SDN deployments use a mixture of vendor-sponsored projects.

Keep in mind that there are some common requirements that all SDN controllers should meet. For example, all controllers should support features such as the OpenFlow protocol. This is because this is a common method for southbound application programming interfaces (APIs) to their switches.