Patent ID: 9374387
Filing Date: 2016-06-21
CPC Classification: H04L

Claim Text:
1. A network device for an industrial control system comprising: a port adapted to communicate industrial control protocol packets over an industrial control network; a switching circuitry coupled to the port adapted to send inbound packets from the port to a destination based on addressing information contained in the inbound packets; and a packet evaluation circuitry coupled to the port, wherein the packet evaluation circuitry is adapted for each of the inbound packets to: (a) evaluate one or more protocol fields contained in the inbound packet to identify a protocol field relating to real-time industrial control before the switching circuitry can send the inbound packet; (b) prevent the inbound packet from being inhibited and allow the inbound packet to be sent by the switching circuitry if the inbound packet contains a particular message relating to real-time industrial control indicated by the one or more evaluated protocol fields, particular message indicating that the device generating the inbound packet has an established connection in the industrial control system; and (c) selectively inhibit the inbound packet from being sent by the switching circuitry if the inbound packet does not contain the particular message for being sent and if a total number of bytes of the inbound packet type exceed a threshold for an outbound port during a given period of time, wherein the inbound packet contains the particular message for being sent if an evaluated protocol field further indicates a valid Connection ID or a valid device ID.