A system can run multiple SHRUB controllers. Each controller has a unique ID number.
In the current implementation each Onload/TCPDirect stack or ef_vi application can attach to a single SHRUB controller. Stacks/applications which attach to the SHRUB controller with a specific ID use the same shared queue and so receive the same traffic.
When a flow (traffic matching a filter) is being received via a specific controller/RXQ, this flow is not available via the Express datapath to applications which have connected to a different SHRUB controller, or which attempt to receive the flow via an Exclusive RXQ. A multicast flow can always be received via the Enterprise datapath.