PROFINET is the standard for industrial Ethernet in automation
It is based on IEC 61158 and IEC 61784 and supports three communications services:
Standard TCP/IP for non-deterministic functions such as parametrization, video/audio transmissions and data transfer to higher level IT systems.
Real Time (PROFINET RT): It bypasses the TCP/IP layers in order to give deterministic performance for automation applications in the 1-10ms range and can be used for typical I/O applications, including motion control and high performance requirements.
Isochronous Real Time (PROFINET IRT): The signal prioritization and scheduled switching deliver high precision synchronization for e.g. motion control application. Bus cycle rates in the micro second range are possible, with jitter in the sub-microsecond range.