D2R: Dataplane-Only Policy-Compliant Routing Under Failures

Abstract

In networks today, the data plane handles forwarding---sending a packet to the next device in the path---and the control plane handles routing---deciding the path of the packet in the network. This architecture has limitations. First, when link failures occur, the data plane has to wait for the control plane to install new routes, and packet losses can occur due to delayed routing convergence or central controller latencies. Second, policy-compliance is not guaranteed without sophisticated configuration synthesis or controller intervention. In this paper, we take advantage of the recent advances in fast programmable switches to perform policy-compliant route computations entirely in the data plane, thus providing fast reactions to failures. D2R, our new network architecture, can provide the illusion of a network fabric that is always available and policy-compliant, even under failures. We implement our data plane in P4 and demonstrate its viability in real world topologies.