FlowVisor is an experimental software-defined networking (SDN) controller that enables network virtualization by dividing a physical network into multiple logical networks. FlowVisor ensures that each controller touches only the switches and resources assigned to it. It also partitions bandwidth and flow table resources on each switch and assigns those partitions to individual controllers. 

FlowVisor slices a physical network into abstracted units of bandwidth, topology, traffic and network device central processing units (CPUs).  It operates as a transparent proxy controller between the physical switches of an OpenFlow network and other OpenFlow controllers and enables multiple controllers to operate the same physical infrastructure, much like a server hypervisor allows multiple operating systems to use the same x86-based hardware. Other standard OpenFlow controllers then operate their own individual network slices through the FlowVisor proxy. This arrangement allows multiple OpenFlow controllers to run virtual networks on the same physical infrastructure. 

The SDN research community considers FlowVisor an experimental technology, although Stanford University, a leading SDN research institution, has run FlowVisor in its production network since 2009. FlowVisor lacks some of the basic network management interfaces that would make it enterprise-grade. It currently has no command line interface or Web-based administration console. Instead, users make changes to the technology with configuration file updates.

This was last updated in March 2013

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