System and Method for Deterministic I/O with Ethernet Based Industrial Networks

Abstract

A networking system is discussed. The system may be used for industrial networks, where deterministic behavior is often valued. Bounded message travel times may be achieved for a first set of network traffic. Additional traffic may be routed over the networking system without interfering with the message travel times associated with the first set of network traffic. Systems and methods for assigning priority to various sets of network traffic are discussed.

What is claimed is: 
     
         1 . A device comprising:
 a first, a second, and a third Ethernet port; and   a network interface connected to each of said Ethernet ports, the network interface configured to:
 for Ethernet frames received on the first port and destined for the second port or third port, ensure that any priority tags of the frames do not indicate a priority that exceeds a predetermined threshold upon transmission from the second port or third port; and 
 for Ethernet frames received on the second port or third port and destined for the second port or third port, preserve the priority level indicated in any priority tags of the received frames upon transmission from the second port or third port, 
   for Ethernet frames received on the first port and destined for the second port or third port, ensure that any priority tags of the frames do not indicate a priority that exceeds the predetermined threshold upon transmission from the second port or third port by setting the priority level of the frames to a default value.