GENI Architecture

The GENI Network architecture is designed to allow:

• Users to set up Layer 2 network topologies best suited for their experiments,
• Experimentation with non-IP protocol stacks and experimenter specified packet forwarding algorithms,
• Multiple concurrent experiments, each of which may use different protocol stacks and packet forwarding algorithms.

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The diagram below shows the GENI network architecture.  It consists of:

1. The control plane.  The control plane is used to discover, reserve, access, program and manage GENI compute and communication resources.  It is represented by the blue links in the diagram.  The control plane runs over the Internet
2. The data plane.  The data plane is set up on demand for each individual experiment.  It is set up according to the experimenter’s specification of the desired network topology, compute resources that connect to the network, bandwidth of individual links, and programmable switches and controllers needed to implement custom packet forwarding algorithms. The data plane is represented by the orange links in the diagram.  It runs over the GENI backbone network including Internet2, regional R&E networks and GENI rack backplanes.

Slicing the network.  GENI network links are sliced by Ethernet VLANs i.e. multiple experiments sharing the same physical link are given different VLANs on that link.  Slicing by VLAN guarantees traffic isolation among experiments (one slice in GENI cannot see packets in another slice) and also provides best-effort performance isolation.

Deep programmability.  GENI allows programmers to control how packets are forwarded within their experiment.

• GENI has compute and storage resources at some of the R&E networks that provide GENI data plane connectivity.  Experimenters can use these resources to instantiate software switches and routers and program them to forward packets as desired.  Examples of R&E networks with compute and storage resources include MAX, SOX, CENIC, MOXI and Starlight.
• GENI has programmable hardware switches on every rack and within some of the R&E networks that provide data plane connectivity.  Most notably, the Internet2 network that provides national data plane connectivity makes its programmable switches available to GENI experimenters.  Programmable switches are OpenFlow capable; experimenters can write controllers to implement custom packet forwarding algorithms.

Network federation and stitching.  GENI is a federated testbed i.e. different organizations host GENI resources and make them available to GENI experimenters.  This include network resources that are owned by regional and national R&E network providers and by campuses hosting GENI racks or wireless base stations.  Setting up the data plane for a GENI experiment may therefore require coordination among multiple network resource providers.  This is done by a process called GENI Stitching.

The figure below illustrates the coordination needed to stitch a Layer 2 link from an experimenter’s compute resource on one rack (Rack A) to a compute resource on another rack (Rack B).  This stitching requires provisioning of VLANs at the regional networks that Racks A and B connect to and at the national backbone network.  Each of these networks needs to allocate and provision a VLAN and they all need to ensure traffic can be exchanged between the VLAN they allocated and the VLAN allocated by their neighboring network.  For details on GENI stitching see the Stitching page on the GENI wiki.

GENI wireless networks.  GENI wireless base stations have backhaul connections to a local GENI rack and connect through the rack to the rest of the GENI network.  This is shown in the GENI network architecture diagram at the top of this page.

Connecting campus resources to GENI.  The best way to connect a campus resources such as a scientific instrument or a research lab to GENI is through the dataplane switch on a  GENI rack.  This is illustrated in the figure at the top of this page.