After many years of development, Software Defined Networks SDN have started to see mainstream acceptance. Considerable work has established standards for the northbound and southbound interfaces of SDN controllers, but much work remains on the development of an eastwest protocol. In this research, we take security, autonomy, and privacy as essential requirements for an eastwest interface. We believe that the properties of permissioned block chains, serializability, immutability, verifiability, and smart contracts, meet these requirements. Using Hyperledger Fabric as our blockchain protocol, we were able to develop a proof-of-concept for an eastwest protocol on the ONOS SDN platform. We demonstrate successfully requesting a connection between separately managed SDN networks which leads to the installation of flows and data transfer between the networks. We further evaluate the impact of network latency on Hyperledger Fabric nodes to complete transactions the results show a linear relationship between per hop network latency and transaction completion time.