Switching device for Ethernet-based fieldbuses

Abstract

The invention relates to a switching device for Ethernet-based fieldbuses. The switching device comprises a primary connection and at least two secondary connections, a plurality of protocol modules, a detection module and at least two first selection elements associated with the at least two secondary connections. The protocol modules are configured to provide switching and / or routing functionalities according to one of several protocols. The detection module is configured to detect predetermined type values ​​in Ethernet frames, generate predetermined selection signals, and, when one of the predetermined type values ​​is detected in a first Ethernet frame, generate the selection signal indicating the protocol associated with the detected type value. The selection elements comprise at least two first selection elements which are each in electrical connection with the at least two secondary connections, wherein for each of the first selection elements the at least two inputs of the respective first selection element are connected to corresponding outputs of the at least two protocol modules and one output of the respective first selection element is connected to the transmission connection of one of the secondary connections.

Description

[0001] The present invention relates to a switching device for Ethernet-based fieldbuses, a gate netlist for field-programmable logic arrays and a programming code for a field-programmable logic array. Background of the invention

[0002] In automation technology, fieldbuses are used to transmit messages or telegrams between different devices, such as controllers and machines in an automated production plant. The messages to be transmitted contain, for example, control commands, control parameters, sensor data or status data. Fieldbuses can be based on Ethernet, whereby the messages, which correspond to the respective fieldbus message format, are transmitted as payload data in Ethernet frames. Examples of Ethernet-supported fieldbuses are PROFINET®, EtherNet / IP®, EtherCAT®, or SERCOS®. Depending on the fieldbus type, the field devices can be interconnected according to various topologies such as ring, star or line topology. For the various fieldbuses in a star topology, the forwarding and routing of messages to the field devices typically occurs using different methods. Description of the invention

[0003] The invention provides a switching device for Ethernet-based fieldbuses, a gate netlist for a field-programmable logic array, and programming code for field-programmable logic arrays according to the independent claims. The dependent claims relate to preferred embodiments of the invention.

[0004] The switching device according to the invention comprises a primary connection and at least two secondary connections, a plurality of protocol modules, a detection module, and a plurality of selection elements. The protocol modules are configured to provide switching and / or routing functionalities according to at least one of a plurality of protocols. The detection module is configured to detect predetermined type values ​​in the Ethernet frames, generate associated selection signals, and, if one of the predetermined type values ​​is detected in a first Ethernet frame, generate the selection signal associated with the protocol corresponding to the detected type value.The selection elements comprise at least two first selection elements, each of which is electrically connected to the at least two secondary interfaces, wherein for each of the first selection elements, the at least two inputs of the respective first selection element are connected to corresponding outputs of the at least two protocol modules, and one output of the respective first selection element is connected to the transmit connection of one of the secondary interfaces. Accordingly, the switching / routing of the switching device is determined by the selection signal generated by the detection module based on the detected type value. Since type values ​​identify specific protocols, the protocol module used is selected according to the protocol used in the received Ethernet-based fieldbus message. The switching device according to the invention thus automatically adjusts to one of the various Ethernet-based fieldbuses.For example, a first (master) device, such as a controller, can be connected to the primary interface, and additional (slave) devices, such as field devices controlled by the controller, can be connected to the secondary interfaces. For this purpose, the switching device is configured by the detection module based on a first Ethernet frame from the first field device.

[0005] In particular, the Ethernet frames conform to the IEEE 802.3 and / or ISO / IEC 8802-3 MAC standards. Furthermore, the type values ​​include, in particular, EtherType values ​​according to the IEEE 802.3 and / or ISO / IEC 8802-3 MAC standards and / or UDP port numbers. Alternatively, it is also possible to implement the type values ​​using customer-specific type values ​​(e.g., including them in the payload field of Ethernet frames).

[0006] According to one embodiment, the primary interface has a transmit port, and the selector elements comprise a second selector element, the output of the second selector element being connected to the transmit port of the primary interface. The inputs of the second selector element are connected to outputs of the corresponding protocol modules. Accordingly, the transmission of messages back to the master device connected to the primary interface is enabled.Since the configuration of the switching device is determined by the first Ethernet frame sent by the (master) device connected to the primary interface, the switching device maintains its configuration according to the protocol suitable for feedback from (slave) devices connected to the secondary interfaces (provided that the master device does not send Ethernet frames resulting in another selection signal while waiting for the feedback).

[0007] According to one embodiment, selection elements comprise at least one third selection element, wherein the output of the at least one third selection element is connected to a corresponding input of a protocol module, and wherein one of the inputs of the at least one third selection element is connected to the receive port of the primary interface, and wherein each of the inputs of the at least one third selection element is connected to the corresponding output of one or more of the protocol modules. Accordingly, a configuration-dependent selection of the source of an input of the protocol module to which the output of the third selection element is connected is possible.

[0008] According to one embodiment, the selection elements comprise at least one fourth selection element, wherein the output of the at least one fourth selection element is connected to a corresponding input of a protocol module, and wherein the inputs of the at least one fourth selection element are connected to associated outputs of the protocol modules. This embodiment enables internal routing of signals between protocol modules depending on the selection signal.

[0009] According to one embodiment, the protocols comprise a standard protocol; wherein the detection module is configured to generate a selection signal signaling the standard protocol upon initialization of the switching device and / or prior to receipt of the first Ethernet frame; and / or wherein each selection element is configured to switch to the state corresponding to the selection signal indicating the standard protocol upon initialization of the switching device and / or prior to receipt of the selection signal from the detection module. Each of the first and, if present, second selection elements can have an input associated with the standard protocol. The standard protocol is, in particular, a (generic) Ethernet routing / switching functionality. The standard protocol enables, for example,communication with all devices connected to the interfaces during a configuration phase of the system after commissioning.

[0010] According to one embodiment, the detection module is configured to maintain the selection signal as long as the switching device is supplied with a supply voltage, or until another selection signal is generated based on a type value of another, second Ethernet frame received at the receive terminal of the primary interface, and / or each selection element is configured to maintain its state after switching to one of the states until another selection signal is generated or as long as the switching device is supplied with a supply voltage. This embodiment allows the configuration of the switching device to be maintained over a certain period of time, e.g., to receive messages from devices connected to one of the secondary interfaces and forward the message to the primary connection.

[0011] According to one embodiment, each selection element is configured to switch, in response to the selection signal, to a state in which none of the inputs of the selection element is connected to the output of the selection element if the selection element does not have an input associated with the protocol specified in the selection signal. This can prevent communication from being routed to a protocol module or port that is not associated with the detected type value and the corresponding protocol.

[0012] According to one embodiment, the detection module is configured to either not generate a selection signal or to maintain the existing selection signal if an Ethernet frame does not contain one of the predetermined type values. Accordingly, after detecting a known type value (in particular, EtherType value, i.e., predetermined type value), the configuration of the switching device is maintained when an Ethernet frame with an unknown type value is received. If the selection signal is a non-permanent signal that configures the selection elements, which then maintain their configured state until a new selection signal is generated, the option of not generating a selection signal results in the selection elements maintaining their state.

[0013] According to one embodiment, the plurality of protocol modules and / or the detection module and / or the plurality of selection elements are implemented on a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). This enables a configurable (e.g., different protocols, protocol modules) implementation of the switching device with fast processing capabilities.

[0014] According to one aspect, a gate netlist is provided which, when implemented on an FPGA, causes the FPGA to implement the protocol modules and / or the detection module and / or the selection elements of the switching device according to embodiments of the switching device. The term "gate netlist" refers, as is common in the field of electronic circuits, to a description of the connectivity of an electronic circuit, including at least a list of electronic components and a list of nodes connecting the electronic components (or their terminals).

[0015] According to one aspect, a programming code (bitstream) for a field-programmable gate array (FPGA) is provided which, when programmed into the FPGA, causes the FPGA to implement the protocol modules and / or the detection module and / or the selection elements of the switching device according to the invention. The term "programming code" refers to code that determines the internal routing and logic in the FPGA, i.e., which elements of the FPGA (gates, logic cells, LUTs, ...) are used, how they are configured, and how signals are routed between them. The programming code can, for example, be stored in a non-volatile memory of the FPGA, such as an EEPROM, and be automatically loaded when the FPGA starts up. When the FPGA starts up, the programming code is loaded, for example, into an SRAM of the FPGA, which determines the internal routing and logic.

[0016] Further advantages and embodiments are described in the description and the accompanying drawings.

[0017] Exemplary embodiments of the invention are schematically illustrated in the drawings. Exemplary embodiments of the invention are described below with reference to the drawings. Character description Fig. 1 shows a switching device according to an exemplary embodiment of the invention. Detailed description of the figure

[0018] Fig. Figure 1 shows a switching device according to an exemplary embodiment of the invention. In the figure, connections between elements are represented as lines with arrows, where the arrows indicate the direction of data transmission.

[0019] The switching device comprises a primary interface 2 and a plurality of secondary interfaces 20, 22, 24. While the exemplary switching device shown has three secondary interfaces, generally at least two secondary interfaces are present. Each of the primary and secondary interfaces has a receive port and a transmit port. In particular, the primary interface has a receive port 6 and a transmit port 8, and the secondary interfaces 20, 22, 24 have receive ports 26 and transmit ports 28. Each interface can have a connector (not explicitly shown), such as an 8P8C jack (RJ45) or another connector used for Ethernet-based networks, for connection to a cable. Furthermore, each interface can have a receiver and a transmitter or a transceiver (e.g.an Ethernet PHY transceiver) to receive signals and provide corresponding internal signals at the receive port and to transmit internal signals provided at the transmit port as signals on the cable (if connected). The term “internal signals” refers to signals within the switching device, e.g., with a voltage level determined by the hardware of the switching device. Alternatively, the receiver and transmitter (or a transceiver) may be provided in the protocol modules (described below). Alternatively, the receiver and transmitter or the transceiver may be part of the switching device. In this case, the interfaces, or more precisely their receive and transmit ports, are (electrical) connections for receiving and transmitting communication signals provided by a device connected to the interfaces (i.e.The Ethernet PHYs connected to the receive and transmit ports can be received and transmitted. This means that the interfaces (i.e., the receive and transmit ports) can be connected to Ethernet PHYs that are not part of the switching device itself.

[0020] The switching device comprises a detection module 14 connected to the receive port 6 of the primary interface 2. The detection module 14 is configured to detect predetermined EtherType values ​​(more generally, "predetermined type values," see below) in the Ethernet frame received at the receive port 6 of the primary interface 2. That is, the detection module 14 receives Ethernet frames from the receive port 6 of the primary interface 2 and analyzes them to determine their EtherType value. That is, the detection module 14 determines (recognizes) whether the EtherType value contained in the EtherType field of the Ethernet frames is one of the predetermined EtherType values. The detection module 14 is optionally also configured to take into account a VLAN tag (if present) in the Ethernet frame during this analysis (VLAN: virtual local area network; VLAN tags are also called 802.1Q tags and marked with the value 0x8100).

[0021] Ethernet frames (and Ethernet blocks) are assumed to conform to the IEEE 802.3 and / or ISO / IEC 8802-3 MAC standards. Accordingly, certain information, such as specific communication protocols, is specified by corresponding EtherType values ​​(referred to in the standards as EtherType or EtherType value). For example, the value 0x88CD represents the Sercos® protocol (specifically Sercos® III), the value 0x8892 represents the PROFINET® protocol, and the value 0x88A4 represents the EtherCAT® protocol, which can also be identified by the EtherType 0x0800 (IP protocol) followed by a UDP (User Datagram Protocol) header with the destination port number 0x88A4.

[0022] In the following description of Fig. 1, for example, and for the sake of simplicity, the detection module is configured to detect predefined EtherType values ​​contained in Ethernet frames according to the IEEE 802.3 and / or ISO / IEC 8802-3 MAC standard. In general, it is possible to use other predefined Type values ​​instead of or in addition to EtherType values. In particular, any field value contained in Ethernet frames that indicates a specific fieldbus can be used, i.e., it is recognized by the detection module and mapped to a selection signal. As already mentioned, for example, a specific UDP port number can indicate a specific protocol, such as the EtherCAT protocol. Another example is the Modbus TCP / IP fieldbus, which is mapped to Ethernet Switching / Routing (ET). As already mentioned, different Type values ​​can be mapped to the same protocol, i.e., they result in the same selection signal being generated.The term “type value” can generally include more than one numeric value, e.g. EtherType 0x0800 followed by a UDP port number 0x88A4 in the case of EtherCAT.

[0023] Furthermore, an additional type field can be inserted into the Ethernet frames (particularly in the payload) by a field device connected to the primary interface. This type field can have predefined type values ​​that are detected by the detection module to generate a corresponding selection signal. In this case, the protocol modules can be configured to remove this type field when routing Ethernet frames from the primary interface to the secondary interfaces and to add this type field (with a corresponding type value) when routing Ethernet frames from a secondary interface to the primary interface, so that off-the-shelf (e.g., commercially available) devices can be connected to the secondary interfaces.

[0024] Based on the detected EtherType value (or generally, type value), the detection module 14 generates and outputs a selection signal 16. The selection signal can be output, for example, via one or more signal lines. The selection signal can be a temporary signal or a permanent signal.

[0025] In particular, the detection module 14 is configured to generate a set of predetermined selection signals. Which selection signal is generated from this set depends on the detected EtherType value (i.e., EtherType values ​​are assigned to selection signals). Multiple EtherType values ​​may result in the same selection signal being output. The set of predetermined selection signals may include a default selection signal that is generated when the switching device, in particular the detection module, is initialized and / or starts (e.g., at the beginning of the provision of a supply voltage or during boot-up) and / or when the EtherType values ​​do not belong to the predetermined EtherType values. In addition, the default selection signal may also be output when a specific EtherType value, i.e., one of the predetermined EtherType values, is detected.Thus, each of the predetermined EtherType values ​​is mapped to one of the predetermined selection signals generated upon detection of the respective EtherType value (different EtherType values ​​can be assigned to the same selection signal). Additionally, certain events can be assigned to one of the predetermined selection signals, such as the default selection signal generated upon the occurrence of this event. These events can be, for example, an initialization or boot-up of the switching device in which none of the predetermined EtherType values ​​is detected in an Ethernet frame.

[0026] The switching device comprises a plurality of protocol modules 30, 32, 34, 36. While in the exemplary embodiment of Fig. 1 shows four protocol modules, the switching device generally comprises at least two protocol modules. Each protocol module has at least one input, generally designated by reference numeral 38, and at least one output, generally designated by reference numeral 40. Each protocol module is configured to provide functionalities, such as routing and / or switching functionalities, according to one of a plurality of (routing) protocols. For example, a first protocol module 30 is configured as an Industrial Ethernet switch, a second protocol module 32 is configured as an EtherCAT slave, a third protocol module 34 is configured as a Sercos slave, and a fourth protocol module 36 provides Ethernet MAC (Media Access Control) functionality in communication with the third protocol module 34 (Sercos slave).So-called UCC frames (UCC: Unified Communication Channel, which is part of the Sercos communication scheme) are exchanged (as indicated by a double-headed arrow) between the third protocol module 34 and the fourth protocol module 36 to enable regular Ethernet switching for UCC frames. Therefore, the protocol modules 34 and 36 together form a gateway for standard Ethernet communication to a Sercos network (e.g., a closed ring topology). For example, the second protocol module 32 (EtherCAT slave) and the third protocol module 34 (Sercos slave) essentially transfer telegrams contained in Ethernet frames from an input 38 to an output 40, as specified in the respective specification (EtherCAT, Sercos). A protocol module, for example, the second protocol module 32, may also include a processing unit 33 that provides some fieldbus-specific telegram processing functions.The third protocol module 34 can also extract and / or add Ethernet telegrams into a Sercos network in exchange with the protocol module 36 (usually a standard Ethernet MAC unit) to provide a gateway for standard Ethernet frames. For this purpose, processing logic 37 organizes the telegram exchange between the protocol modules 34 and 36.

[0027] In the Fig. In the embodiment shown in Figure 1, there are three (routing / switching) configurations: (generic) Ethernet switching / routing (ET), EtherCAT (EC), and Sercos (S3). Specifically, more than one fieldbus protocol (as indicated by the EtherType) can correspond to the same configuration. For example, Ethernet values ​​of fieldbuses that use (generic) Ethernet switching / routing (ET) can all be associated with ET. As in many cases, EtherType values ​​indicate specific protocols; each protocol is associated with (or corresponds to) at least one EtherType value (the predetermined EtherType value). As already mentioned, there can be other telegram criteria of field values ​​besides the EtherType, especially for some of the fieldbuses not explicitly mentioned above. Since the selection signal is issued based on the detected fieldbus type, each selection signal is an indication of a (routing) configuration. The protocols can be a standard protocol, e.g.ET, where the above-mentioned standard selection signal indicates the standard protocol.

[0028] At the Fig. In the embodiment shown in Figure 1, the receive port 6 of the primary interface 2 is connected to the respective inputs 38 of the second protocol module 32 and the third protocol module 34. These connections can be considered direct connections. In addition, the receive port 6 of the primary interface 2 is connected to an input of a (third) selection element 68 (see below for a description of the selection elements), with the output of the selection element being connected to an associated input of the first protocol module 30. This connection can be considered an indirect connection. In general, the receive port 6 of the primary interface 2 is connected to the respective inputs 38 of at least one or at least two of the protocol modules (in the sense of a direct connection).In any case, Ethernet frames received at the receive port 6 of the primary interface 2 can be transmitted to at least two of the protocol modules and processed there, assuming that if there is only one direct connection, there is an additional indirect connection.

[0029] The switching device further comprises a plurality of selection elements 60, 62, 64, 66, 68, for example multiplexers, which are connected to the detection module 14 to receive the output selection signal 16. Each of the selection elements 60, 62, 64, 66, 68 is configured to switch to one of predetermined different states in response to receiving the selection signal, wherein the state to which the selection element switches is dependent on the selection signal. Different selection elements may have different sets of states. Each selection element 60, 62, 64, 66, 68 has an output and at least two inputs 72, 74, 76. For each selection element, each input is assigned to one of the protocols. A selection module may have fewer inputs than protocols.

[0030] The state set comprises at least a number of states, also called connected states, corresponding to the number of inputs. If a selection element is in one of these connected states, (exactly) one of the inputs is connected to the output. Optionally, the state set of each selection element (independent of other selection elements) comprises a state, also called a disconnected state, in which none of the inputs is connected to the output. For each selection element, each of the predetermined selection signals is assigned to one of the states of the selection element, i.e., the selection element is switched to the corresponding state when the selection signal is received and / or present (in other words, in response to the generated selection signal).If a select signal is received and / or present that is associated with a connected state, the input associated with the protocol identified by the select signal is connected to the output. If a select signal is newly generated and / or present that is not associated with a connected state, i.e., associated with the unconnected state, no input is connected to the output. Different select signals may correspond to the disconnected state. One of the states of each select may furthermore (independently of other select elements) be a default state, to which the select element is switched if no select signal has been received (or is present), or upon initialization and / or boot-up of the switching device and / or the select element, and / or in response to the default select signal.

[0031] For example, with regard to Fig. 1, in response to the selection signal indicating the ET protocol (regular Ethernet routing / switching functionality, e.g., when EtherType value 0x8892, indicating PROFINET RT, is detected), a first input 72 of the selection elements 60, 62, 64, 66, 68 is connected to the output of the respective selection element. A second input 74 of the selection elements 60, 62, 64, 66 is connected to the output of the respective selection element in response to the selection signal indicating the EC protocol (EtherCAT routing functionality, e.g., when EtherType value 0x88A4, which detects EtherCAT, is detected). A third input 76 of the selection elements 60, 66, 68 is connected to the output of the respective selection element in response to the selection signal indicating the S3 protocol (Sercos routing functionality, e.g., when the EtherType value 0x88CD, indicating that Sercos is detected, is detected).As shown, some of the select elements do not have connected states corresponding to each of the protocols. That is, select signals indicating a specific protocol can result in the disconnected state for these select elements. Consequently, no data flow occurs at the select element's output.

[0032] The selection elements include at least two (in the example of Fig. 1 three) first selection elements 60, 62, 64, which are in 1-to-1 association with the secondary interfaces 20, 22, 24. For each first selection element, the output of the selection element is connected to the transmit terminal 28 of the secondary interface corresponding to the selection element. The inputs of each first selection element 60, 62, 64 are connected to associated outputs 40 of at least two (corresponding to the number of inputs of the corresponding first selection element) of the protocol modules 30, 32, 34, 36.

[0033] In particular (since each input is associated with a protocol), each input is connected to a corresponding output of the protocol module that provides routing and / or switching functionality according to the protocol to which the input is associated, or, if more than one protocol module provides routing and / or switching functionality according to that protocol, to one of those protocol modules.

[0034] The selection elements optionally comprise a second selection element 66. The output of the second selection element 66 is connected to the transmit port 8 of the primary interface 2. The inputs of the second selection element 66 are connected to associated outputs 40 of at least two (corresponding to the number of inputs of the associated first selection elements) different protocol modules 30, 32, 34, 36. In particular, as with the first selection elements, each input is connected to a corresponding output of the protocol module that provides routing and / or switching functionalities according to the protocol to which the input is associated, or, if more than one protocol module provides routing and / or switching functions according to this protocol, to one of these protocol modules.

[0035] The selection elements optionally further comprise at least a third selection element 68 (in the embodiment of Fig. 1, a third selection element is included). The output of the third selection element 68 is connected to an associated input 38 of the first protocol module 30. One input of the third selection element 68 is connected to the receive port 6 of the primary interface 2 (i.e., it provides the aforementioned indirect connection of the receive port 6 of the primary interface 2 and a protocol module). The other inputs of the third selection element are connected to corresponding outputs of one or more protocol modules (depending on the protocol module connected to the output of the third selection element). In the Fig.In the embodiment illustrated in Figure 1, an input of the third selection element 68 is connected to the fourth protocol module 36. Similar to the first and second selection elements, each of the other inputs is connected to a corresponding output of the protocol module that provides routing and / or switching functionalities according to the protocol, or, if more than one protocol module provides routing and / or switching functions according to that protocol, to one of those protocol modules.

[0036] Additionally, the selection elements optionally comprise at least a fourth selection element (not shown). The output of the fourth selection element is connected to a corresponding input of a protocol module. The inputs of the fourth selection element are connected to the outputs of at least two protocol modules. The fourth selection element (if present) provides internal routing between protocol modules. As for the first and second selection elements, each input is connected to a corresponding output of the protocol module, which provides routing and / or switching functionality according to the protocol to which the input is assigned or, if more than one protocol module provides routing and / or switching functions according to that protocol, to one of those protocol modules.

[0037] Each of the modules and elements, i.e., the detection module 14, the protocol modules 30, 32, 34, 36, and the selection elements 60, 62, 64, 66, 68, can be implemented independently as a hardware module and / or a software module. Different modules or elements can be implemented on different hardware modules.

[0038] In particular, the detection module 14 and / or the protocol modules 30, 32, 34, 36 and / or the selection elements 60, 62, 64, 66, 68 can be implemented on an FPGA or as an ASIC. Inputs and outputs of the FPGA can then be connected to Ethernet PHY transceivers. Alternatively, Ethernet PHY transceivers can also be implemented at least partially on the FPGA or ASIC.

Claims

[1] Switching device for Ethernet-based fieldbuses, comprising a primary interface (2) with a receive connection (6) and at least two secondary interfaces (20, 22, 24), each with a transmit connection (28); characterized by several protocol modules (30, 32, 34, 36), wherein each protocol module is configured to provide switching and / or routing functionalities according to one of several protocols, wherein the receiving port (6) of the primary interface is connected to associated inputs (38) of at least one of the protocol modules; a detection module (14) configured to detect predetermined type values ​​of Ethernet frames received at the receiving port (6) of the primary connection and configured to generate selection signals, wherein each protocol is assigned at least one of the predetermined type values ​​and each of the selection signals is assigned to one of the protocols, wherein the detection module (14) is further configured, when one of the predetermined type values ​​is detected in a first Ethernet frame, to generate the selection signal (16) associated with the type value identifying the protocol, a plurality of selection elements (60, 62, 64, 66, 68), each having at least two inputs (72, 74, 76) and one output, each input being assigned a protocol, each selection element being switchable into different states, in each state one or none of the inputs of the respective selection element being connected to the output of the respective selection element, wherein each selection element (60, 62, 64, 66, 68) is arranged to switch to one of the states in response to the selection signal, so that the input (72, 74, 76) of the protocol associated with the selection signal (16) is connected to the output of the selection element; wherein the selection elements comprise at least two first selection elements (60, 62, 64) which are connected to the at least two secondary connections (20, 22, 24), wherein each of the at least two inputs (72, 74, 76) of the first selection elements is connected to one of the at least two protocol modules (30, 32, 34) and the respective output of the first selection element is connected to the transmission connection (28) of the secondary connection. [2] The switching device of claim 1, wherein the Ethernet frames are compliant with the IEEE 802.3 standard and / or the ISO / IEC 8802-3 MAC standard and / or comprise EtherType values ​​according to the IEEE 802.3 standard and / or the ISO / IEC 8802-3 MAC standard; and / or the type values ​​comprise a UDP port number. [3] Switching device according to one of the preceding claims, wherein the primary connection (2) has a transmission connection (8) and the first selection elements comprise a second selection element (66), the output of the second selection element (66) being connected to the transmission connection (8) of the primary connection, and the inputs (72, 74, 76) of the second selection element being connected to correspondingly assigned outputs of at least two of the protocol modules (30, 32, 34). [4] Switching device according to one of the preceding claims, wherein the selection elements comprise at least one third selection element (64), wherein the output of the at least one third selection element (64) is connected to an associated input of a protocol module (30), and wherein one of the inputs (72) of the at least one third selection element is connected to the receive terminal (8) of the primary interface (2), and wherein each of the inputs (76) of the at least one third selection element (64) is connected to a correspondingly associated output of one or more of the protocol modules (36). [5] Switching device according to one of the preceding claims, wherein the selection elements comprise at least one fourth selection element, wherein the output of the at least one fourth selection element is connected to a correspondingly assigned input of a protocol module, and wherein the inputs of the at least one fourth selection element are connected to correspondingly assigned outputs of at least two of the protocol modules. [6] Switching device according to one of the preceding claims, the protocols comprising a standard protocol; wherein the selection module (14) is configured to generate the selection signal (16) indicating the standard protocol upon initialization of the switching device and / or prior to receipt of the first Ethernet frame; and / or wherein each selection element (60, 62, 64, 66, 68) is configured to change to the state corresponding to the selection signal indicating the standard protocol upon initialization of the switching device and / or prior to receipt of the selection signal (16) from the detection module (14). [7] Switching device according to one of the preceding claims, wherein the detection module (14) is configured to maintain the selection signal (16) as long as a supply voltage is made available to the switching device or until a different selection signal is determined based on a type value of another, second Ethernet frame received at the receive port of the primary interface; and / or wherein each selection element (60, 62, 64, 66, 68) is configured to maintain its state after switching to one of the states until another selection signal is generated or as long as a supply voltage is provided for the switching device. [8] Switching device according to one of the preceding claims, wherein each selection element (60, 62, 64, 66, 68) is configured such that the selection element switches to a state in which none of the inputs (72, 74, 76) of the selection element is connected to the output of the selection element when the selection element does not have an input associated with a protocol indicated in the selection signal (16). [9] Switching device according to one of the preceding claims, wherein the detection module (14) is configured, if an Ethernet frame does not contain any of the predetermined type values, not to generate a selection signal or to maintain the applied selection signal (16) [10] Switching device according to one of the preceding claims, wherein the protocol modules (30, 32, 34, 36) and / or the recognition module (14) and / or the selection elements (60, 62, 64, 66, 68) are implemented on a programmable gate array, FPGA or in an application-specific integrated circuit, ASIC. [11] Gate netlist which, when implemented on a field programmable gate array, FPGA, causes the FPGA to implement the protocol modules (30, 32, 34, 36) and / or the selection module (14) and / or the selection elements (60, 62, 64, 66, 68) of the switching device according to one of claims 1 to 10. [12] Programming code for a field programmable gate array, FPGA, which, when programmed in the FPGA, causes the FPGA to implement the protocol modules (30, 32, 34, 36) and / or the detection module (14) and / or the selection elements (60, 62, 64, 66, 68) of the switching device according to one of claims 1 to 10.

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