When receiving a packet the device will place the packet on a queue with its hard interrupt (threaded in RT). The sirq-net-rx is responsible for finding out what to do with the packet. It may forward it to another box if the current box is used as a router, or it will find the task the packet is for. If that task is currently waiting for the packet, the softirq might hand it off to that task and the task will handle the rest of the processing of the packet.
