  Providing network reliability as well as low and predictable latency is
important especially for Industrial Automation and Control Networks. However,
diagnosing link status from the control plane has high latency and overhead. In
addition, the communication with the industrial controller may impose
additional network latency. We present FastReact - a system enabling In-Network
monitoring, control and caching for Industrial Automation and Control Networks.
FastReact outsources simple monitoring and control actions to evolving
programmable data planes using the P4 language. As instructed by the Industrial
Controller through a Northbound API, the SDN controller composes control
actions using Boolean Logic which are then installed in the data plane. The
data plane parses and caches sensor values and performs simple calculations on
them which are connected to fast control actions that are executed locally. For
resiliency, FastReact monitors liveness and response of sensors/actuators and
performs a fast local link repair in the data plane if a link failure is
detected. Our testbed measurement show that FastReact can reduce the
sensor/actuator delay while being resilient against several failure events.
