The OpenFlow switch is a basic forwarding element, which is accessible via the OpenFlow protocol and interface. Although this setup would appear to simplify the switching hardware at first glance, flow-based SDN architectures such as OpenFlow may require additional forwarding table entries, buffer space, and statistical counters that are not very easy to implement in traditional switches with application specific ICs (ASICs).
In an OpenFlow network, switches come in two flavors: hybrid (OpenFlow enabled) and pure (OpenFlow only). Hybrid switches support OpenFlow in addition to traditional operation and protocols (L2/L3 switching). Pure OpenFlow switches have no legacy features or onboard control and completely rely on a controller for forwarding decisions.
Most of the currently available and commercial switches are hybrids. Since OpenFlow switches...