Implementing Layer 2 Network Virtualization Using OpenFlow: Challenges and Solutions

Novel approaches for network virtualization at Layer 2 which are not based on VLAN have became a real possibility since the appearance of Software Defined Networking and OpenFlow in particular. We have deployed our own network virtualization facility based on Layer 2 prefixes using OpenFlow: the EHU OpenFlow Enabled Facility (EHU-OEF). We have implemented a solution that allows research and production traffic to share the same infrastructure without interfering with each other. It requires minimum configuration in the case of researchers and none in the case of non-technical users. In our deployment we found several challenges with Layer 2 protocols that use broadcast/multicast addresses due to the use of OpenFlow. In order to solve those challenges, we developed several custom modules for the OpenFlow controller and made some changes in the Flow Visor. Finally, the design of the EHU-OEF facility as well as some configuration details are described.