Adaptive Multipath Routing based on Hybrid Data and Control Plane Operation

Control plane programmability, primarily enabled by SDN/OpenFlow, has brought new impetus to already consolidated management and planning practices in the area of computer networks. However, applications that require high responsiveness and demand more dynamic mechanisms executing beyond the control plane can only be effectively exploited through interactions with the data plane, where decisions and reactive responses can be made at line rate. P4 achieves this goal by providing directives that allow a certain level of control over the hardware that performs packet forwarding tasks, bringing programmability to the data plane. In this paper, we present a multipath routing strategy that takes full advantage of a hybrid SDN/OpenFlow and P4 architecture. In the data plane, P4 and the Flowlet abstraction are used to actively perform load balancing and routing over multiple asymmetric paths, in addition to monitor active links. In the logically centralized control plane, the overall view of the network is leveraged to perform more elaborate passive tasks, which include mapping paths, configuring devices and updating routes asynchronously. Experimental evaluations are conducted in which we analyze different strategies for choosing the routes that provide the best results based on RTT values received from the switches.