Detecting Network Topology and Packet Trajectory with SDN-enabled FPGA Platform

Software-defined networking brings extra complexity to debugging while enhancing network manageability. The competition between applications and subtle bugs in controllers or switches may cause inconformity between control plane logic and data plane behavior. Tracing packet trajectory through the network is a direct way to verify whether data plane processes packets correctly according to control plane policy. We introduce NetMagic, a SDN-enabled switch based on FPGA which can be managed remotely using a custom protocol, and present the detection of network topology and packet trajectory in the network consists of NetMagics. We use probe packet to reproduce the trajectory of arbitrary production packet only by adding three rules per NetMagic to record path history in on-board RAM. The core idea is that we install a hash function both in the controller and NetMagic to process the header of probe packets which considerably reduce the usage of RAM space and facilitate the collection of trajectory data. The evaluation shows that our implementation works properly under high concurrency of tracing tasks by adjusting the parameter of hash function.