  This paper gives an overview on how Software Defined Networking (SDN)
principles can be applied to existing Ethernet merchant silicon considering the
requirements modern networks face. We show that existing Layer 2 features
specified by IEEE 802.1Q support SDN. The bridge architecture supports control
plane/data plane split by design and also allows for external control e.g. by
an SDN Controller. The data plane provided by existing chips is feature rich
for network virtualization and supports even more features like OAM. We outline
the principles of SDN over bridges and show a number of possibilities for
further research and development.
