CZ34436U1 - Connection of control systems with a higher degree of security integrity for connecting to devices with a lower degree of security in the communication infrastructure of Ethernet networks - Google Patents

Description

Connection of control systems with a higher degree of security integrity for connection to devices with a lower degree of security in the communication infrastructure of Ethernet networks

Field of technology

The subject of the technical solution is the connection of control systems with a higher degree of security integrity for connection to devices with a lower degree of security in the communication infrastructure of Ethernet networks.

Prior art

Currently, a pair of bridges / routers equipped with Ethernet and serial devices are used for communication of devices with a higher degree of safety integrity, eg railway electronic switchboards, with devices with a lower degree of safety integrity, eg technological superstructures of security devices, to their remote diagnostics systems and others. ports directly connected by a serial synchronous interface. One side of the communication is configured as a modem, the other side as a terminal. The one-way connection cable has only the necessary signals (clock, data, control) connected, which have a transmitter on the modem side and a receiver on the terminal side. The cable does not contain other wires for signals of the opposite direction of communication at all. At the same time, the selection of a suitable synchronous communication protocol ensures one-way passage of data through the communication channel. Subsequent systems connect to the Ethernet ports of bridges / routers. Only Ethernet broadcast traffic passes through the one-way separation solved in this way. Other types of Ethernet traffic are filtered and do not pass. The disadvantage of the current one-way separation solution is the low transmission speed of the metallic serial interface and the less resistant galvanic separation of both sides of the communication. Furthermore, its larger space and power requirements.

The essence of the technical solution

The technical solution concerns the connection of control systems with a higher degree of security integrity for connection to devices with a lower degree of security in the communication infrastructure of Ethernet networks.

The essence of the technical solution is that the data switch of the first side network X, intended for connection of protected elements of closed network communication infrastructure, is unidirectionally connected with the data switch of the second side network Y, intended for connection of open network elements, this hardware connection of both of data switches is adapted for the passage of unidirectional data traffic from a closed network to an open network without its feedback, while simultaneously galvanically separating both sides X and Y from each other.

The interconnection of the two data switches is by means of a single-fiber optical patchcord connected on the first side X to its transmitting part TX with light emitting diode and on the other side Y to its receiving side RX with photodiode so that the first side X port is opened at the same time. for transmitting toward the second side Y by treating the unconnected input of the first side X with a signal at the physical level of the PHY without useful data.

Both sides X, Y are equipped with a separate microcontroller to provide operation and indication functions and diagnostics for the operation of UDP / IP multicast and UDP / IP unicast operation, equipped with mutually independent USB interface for uploading configuration parameters and diagnostics.

The connection contains voltage converters for data separation also at the supply level in the case of supplying both sides X, Y from the same source, while both sides X, Y are galvanically separated from each other.

-1 CZ 34436 UI

Explanation of drawings

Fig. 1 is a block diagram of an exemplary embodiment of a technical solution with a one-way connection of two data switches and other support parts.

Examples of technical solution

Fig. 1 shows an example of the connection of control systems with a higher degree of security integrity for connection to devices with a lower degree of security in the communication infrastructure of Ethernet networks. The network data switch of the first side X, intended for the connection of the protected elements of the closed network communication infrastructure, is unidirectionally connected to the data switch of the network of the second side Y, which is intended for the connection of the open network elements. This hardware interconnection of both data switches is adapted to pass one-way data traffic from a closed network to an open network without affecting it so that the first side X is galvanically separated from the second side Y. Unidirectionality is achieved by using a single fiber optical cable directly connecting optical Ethernet ports both switches, which on the first side X is connected only to the transmitting Tx connector and on the other side Y only to the receiving Rx connector. At the same time, it is ensured that the port of the first side X is opened for transmission towards the second side Y by treating the unconnected input of the first side X with a signal at the physical level PHY without useful data. Without this treatment, the optical port of the first side X would not start transmitting data at all.

In the case of power supply of both sides from the same source, the data separation is also ensured at the power supply level, by means of voltage converters and by the fact that the X and Y sides are galvanically separated from each other.

This solution allows you to pass the following types of data traffic:

Ethernet broadcast passes in the forward direction without restriction (without further modifications). In the opposite direction, all types of traffic are hardware-blocked in all circumstances, regardless of configuration.

UDP / IP multicast, where the list of addresses of multicast groups whose traffic needs to be transmitted is inserted into the configuration of the first page X of one-way separation. Subsequently, the appropriate protocol (eg IGMPv2) ensures login to individual groups (instead of devices behind the one-way department, which in principle are not capable of doing so) and delivery of their operation from source devices to ports of the first party X. At the same time, the output port is configured for each group in the direction of the other side Y, where the traffic is to be forwarded.

UDP / IP unicast, which uses the insertion of static records both into the MAC and ARP table of the first page X of the one-way department itself, as well as the MAC and ARP table of devices connected to the first page X. With a standard solution for such data transfer, they would be discarded. This is because the first side X cannot receive information from the second side Y that said device is on a given port, due to the unidirectionality.

As mentioned, the interconnection of the two data switches is by means of a single-fiber optical patchcord connected on the first side X to its transmitting part TX, e.g. with a light emitting diode LED and on the other side Y to its receiving side RX e.g. with a photodiode. This connection is equivalent in its properties to the galvanic separation by the optocoupler; it is not necessary to consider the undesired creation of a communication connection in the opposite direction (from the receiving transistor to the transmitting diode). Unused optical interface connectors are blinded and their physical location does not allow unwanted communication connections between the unconnected X-side and Y-side connectors. Operation in the Y-X-side direction is thus hardware-blocked in all circumstances, regardless of the device configuration.

The X and Y sides of the device are galvanically separated from each other, and therefore it is not necessary to consider the undesired establishment of a communication link in the direction from the Y side to the X side via the power supply

- 2 CZ 34436 Group UI. This is achieved by a wide insulation gap on the PCB and power supply via a separate DC / DC converter with high electrical strength, for each side.

Both sides X, Y are preferably provided with a separate microcontroller to ensure operational 5 (UDP / IP multicast and UDP / IP unicast operation passage) and indication functions and diagnostics, which is equipped with an independent USB interface for recording configuration parameters and diagnostics. . In the case of power supply of both sides X, Y from the same source, the data separation is also at the power supply level, by means of voltage converters, where both sides X, Y are galvanically separated from each other.

it

The main area of application of the presented technical solution is to ensure one-way communication from systems of devices with higher degree of safety integrity SIL, eg railway electronic interlocks - SIL4, to devices with lower degree of SIL, eg technological superstructures of security devices, to systems of their remote diagnostics and others) , excluding the possibility of a negative effect on the safety of security devices. The solution can also be used in other closed communication infrastructure systems equipped with Ethernet interfaces, from which it is necessary to unidirectionally take data into subsequent open systems, without these open systems being able to affect the closed infrastructure in any way.

Claims (4)

CLAIMS FOR PROTECTION 1. Connection of control systems with a higher degree of security integrity for connection to devices with a lower degree of security in the Ethernet communication infrastructure, characterized in that the data switch of the first party network (X) intended for connection of protected elements of the closed network communication infrastructure is unidirectional. connected to the data switch of the network of the other side (Y), which is intended for connection of open network elements, this hardware connection of both data switches is adapted to pass one-way data traffic from closed network to open network without its feedback, while simultaneously galvanically separating both sides (X) and (Y) to each other. Connection according to Claim 1, characterized in that the two data switches are interconnected by means of a single-fiber optical patchcord connected on the first side (X) to its light-emitting LED transmitting part (TX) and on the other side (Y). to its receiving side (RX) with a photodiode so as to simultaneously ensure that the first side port (X) is opened for transmission to the second side (Y) by treating the unconnected input of the first side (X) with a PHY physical level signal without useful data. Wiring according to claim 1 or 2, characterized in that both sides (X, Y) are provided with a separate microcontroller for providing operation and indication function and diagnostics for the passage of UDP / IP multicast and UDP / IP unicast traffic, provided with each other on independent USB interface for uploading configuration parameters and diagnostics. Connection according to one of Claims 1 to 3, characterized in that it comprises voltage converters for data separation also at the supply level in the case of supplying both sides (X, Y) from the same source, both sides (X, Y) being galvanically separated.