IO and network management are faced with increasing speed requirements
Low physical I/O protocols or device management have always been handled by a hardware device, simply because line survey or reaction to a bus change need very short reaction time. It would require a huge amount of processing power in order to be fast enough to comply with the bus management physical and timing requirements. But once the physical layer has been handled by these components, it can still be up to a processor to undertake data handling and low-level protocol management.
Dedicated process and interruption management are the common answer in order to accomplish these tasks.