Providing a High Level Abstraction for SDN Networks in GENI

Software Defined Networks make it possible to decouple routing from forwarding, allowing the routing decisions to be made by a (logically)centralized controller which are then communicated to the switches in the network (for example, via the Open Flow protocol). One problem facing end users is the need to map high level abstractions - like the path a flow should take - to a set of low level forwarding rules tailored to, and installed at, every switch along the path. Installing such rules manually is tedious and error prone, and writing a controller program to do it is equally, if not more, challenging. In this paper, we propose a new set of tools that allow users (experimenters)to easily map their high level routing policies to low level Open Flow rules, and to help users reverse engineer high level policies from the installed set of low level flow rules. The tools provide users with the abstraction of end-to-end flows that users can install, list, and delete. The tools automatically handle the details of computing and installing all the rules needed to implement end-to-end flows, and are also capable of identifying flows and, if desired, removing flows that already exist. The tools have been implemented as modules in the GENI Desktop providing users with a graphical interface to their flows. In addition, we have implemented a module to monitor the performance of flows that have been installed. We describe our prototype implementation and present performance numbers obtained via the service.