Slice-based network transit service: Inter-domain L2 networking on ExoGENI

The GENI network testbed was designed to enable experimentation with network protocols by offering the capability to construct virtual networks at the link layer (L2). GENI users build virtual networks in their GENI slices that span resources on multiple GENI aggregates, linked by L2 network circuits from network fabric providers (e.g., Internet2). This paper summarizes new features for cross-slice stitching in the ExoGENI deployment. They enable slice owners to create L2 links crossing slice boundaries within ExoGENI racks (OpenStack cloud sites), including links to slices owned by other tenants. Like other operations on virtual networks in ExoGENI, cross-slice stitching is dynamic and programmatically controlled. Users can adapt the network topologies of their slices and their interconnections with other slices over time. Cross-slice stitching expands the potential of GENI as a platform for inter-domain network experimentation, including tenant slices that provide high-speed network-based services to other slices. This paper reports on a simple demonstration experiment for ExoGENI cross-slice stitching: a network transit service that runs within a slice, manages a shared circuit topology on behalf of customer slices that link to it, and routes customer traffic over its shared network backbone topology. This experiment shows the potential of cross-slice stitching to address a key limitation of GENI: the cost and limited availability of high-speed network circuits for use within GENI virtual networks.