Ring-shaped avionics communication network, and associated civil aircraft

Abstract

Ring Avionics Communication Network and Associated Civil Aircraft. The invention relates to a ring avionics communication network (15) comprising at least three interconnected communication nodes (20), each node having a pair of communication ports (Rx1, Tx1; Rx2, Tx2) and being connected between respective preceding and following nodes, at least one node (20MA) having a sequencing module (25) configured to generate data transport frames, each node being intended to be connected to a respective avionics device (18) and having a processing module (28) for, via said frames, receiving data to said device and / or sending data from said device, at any given time, only one of the nodes (20) being configured to generate the transport frames, the sequencing module (25) being activated for only one of the nodes at a time. Figure for the abstract: Figure 1

Description

Title of the invention: Ring-shaped avionics communication network, and associated civil aircraft

[0001] The present invention relates to an avionics communication network, intended to be carried on board an aircraft.

[0002] The invention also relates to a civil aircraft comprising such an avionics communication network and avionics equipment interconnected via said network.

[0003] The invention lies in the field of internal communication networks in avionics, or more generally in embedded networks that are highly constrained in terms of availability (redundancy) and integrity (content verification with time-deterministic exchanges).

[0004] The ARINC 664 Part 7 standard, also known as A664 p7, has become the standard for recent major aircraft programs as the internal communication network for onboard avionics. It is a star network organized around several switches that allow a large number of onboard devices to be interconnected. This standard provides a high level of data transport integrity and also ensures a high level of network availability by duplicating the communication routers to be tolerant to router failures.

[0005] However, a network conforming to this standard has, in particular, the following defects.

[0006] The size, weight, and power consumption (SWaP) of such a network are not optimal. Indeed, such a network requires at least two switches to ensure network integrity, and often a larger number of switches to ensure network availability, which degrades the size, weight, and power consumption of the solution. It should be noted that this type of network has a significant SWaP footprint, which penalizes small networks: as soon as three devices are connected, two switches are required to ensure the integrity and availability of this mini-network.

[0007] The cost of switches degrades the overall cost of such a network and the reliability of the switch is taken into account by the redundancy of the communication links and therefore of the switches.

[0008] Switches generate a switching delay resulting in latency in data transmission. This latency depends on the switch topology, but also on the volume of data being switched. A worst-case latency can be calculated once all data flows are known through statistical analysis. The latency variation, or jitter, affecting each data point is also calculated and must be controlled and contained, which requires a low theoretical bandwidth utilization rate, below 50%.

[0009] Such a network also lacks determinism, and designers of architectures based on such a network deal with a worst-case scenario of latency and jitter, which restricts its application to "soft" real-time architectures. For example, voice transmission over the network, which is highly sensitive to jitter, can hardly be considered on such a network, nor can systems with millisecond data processing requirements. Furthermore, if new equipment is added to such a network, with new data flows, the network's latency and jitter characterization must be completely reassessed.

[0010] The aim of the invention is then to provide an improved avionics communication network.

[0011] To this end, the invention relates to a ring-shaped avionics communication network, intended to be carried on board an aircraft and comprising at least three communication nodes connected to each other in the shape of a ring,

[0012] each communication node comprising at least one pair of communication ports and being directly connected between a previous node and a subsequent node respectively via two distinct ports respectively, the communication ports of two successive nodes of the ring being connected to each other via a wired data link,

[0013] at least one communication node comprising a sequencing module configured to generate data transport frames, each frame circulating in a loop successively from node to node,

[0014] each communication node being intended to be connected to a respective avionics equipment and comprising a processing module configured to, via the generated frames, receive data destined for said avionics equipment from another avionics equipment and / or to send data from said avionics equipment to at least one other avionics equipment,

[0015] at a given time instant, only one of the communication nodes being configured to generate the data transport frames, the sequencing module being activated for only one of the communication nodes at a time.

[0016] According to other advantageous aspects of the invention, the network comprises one or more of the following features, taken individually or in all technically possible combinations:

[0017] - each communication node includes the sequencing module and the module treatment;

[0018] - at least one communication node includes a monitoring module configured to compare an inter-frame period to a predefined range of values, a frame anomaly is detected if the inter-frame period does not belong to said range, the inter-frame period being the difference between two time instants of reception of successive frames by the node containing the monitoring module;

[0019] each communication node preferably comprising the monitoring module and the processing module;

[0020] the monitoring module preferably being still activated for all communication nodes;

[0021] - each communication node includes the sequencing module, the module monitoring and processing module;

[0022] the monitoring module being preferably activated for all communication nodes;

[0023] - among the communication nodes, two communication nodes, called nodes master nodes each include the sequencing module and the monitoring module, the sequencing module being activated for one master node, called the active master node, and the monitoring module being activated for the other master node, called the passive master node;

[0024] communication nodes, called slave nodes, other than master nodes, preferably comprising only the processing module among the sequencing, monitoring and processing modules;

[0025] - each communication node has a first pair of ports communication and a second pair of communication ports, redundant with the first pair; the communication ports of the first pairs being successively connected to each other via first wired data links, and the communication ports of the second pairs being successively connected to each other via second wired data links, redundant with the first links;

[0026] - between two successive nodes of the ring, the first and second wire connections are arranged in parallel with each other; and the processing modules of said nodes are configured to circulate data in a first direction on the first link, and respectively in a second direction, opposite to the first direction, on the second link;

[0027] - each pair of ports comprises a receiving port and a transmitting port; and

[0028] + if both ports of the first pair are functional, the processing module is configured to acquire a frame received on the receiving port of the first pair, to process said frame, and then to send the processed frame via the transmitting port of the first pair; and the processing module is configured to transfer without processing, to the transmitting port of the second pair, each frame received on the receiving port of the second pair;

[0029] + if the receiver port of the first pair is malfunctioning, the processing module is configured to acquire a frame received on the receiving port of the second pair, to process said frame, and then to send the processed frame via the transmitting port of the first pair; and

[0030] + if the transmitter port of the first pair is malfunctioning, the processing module is configured to acquire a frame received on the receiving port of the first pair, to process said frame, and then to send the processed frame via the transmitting port of the second pair;

[0031] - at least one communication node includes an additional pair of ports communication configured to be connected to another communication network;

[0032] - the sequencing module is configured to generate transport frames of data in the form of virtual links according to the ARINC 664 Part 7 standard, and to associate a respective inter-frame space with each virtual link, the inter-frame space being a minimum duration between the start times of two successive frames of the corresponding virtual link; and

[0033] - for each data transport frame, the processing module of a single node respective is authorized to write data into said frame for sending data to one or more of the other equipment, and the processing modules of all other nodes are only authorized to read data from said frame.

[0034] The invention also relates to an aircraft comprising a ring-shaped avionics communication network, as defined above, and avionics equipment interconnected via said network.

[0035] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0036] [Fig.1] [Fig.1] is a schematic representation of an aircraft according to the invention, comprising an avionics installation including an avionics communication network and avionics equipment interconnected via said network, the network comprising a plurality of communication nodes linked together in the form of a ring;

[0037] [Fig.2] [Fig.2] is a more detailed schematic representation of a master node communication, and respectively a slave communication node; as well as the generation; by the master node; of data transport frames in the form of virtual links;

[0038] [Fig.3] [Fig.3] is a representative view of the time spacing between data transport frames; as well as the structure of a respective frame;

[0039] [Fig.4] [Fig.4] is a view illustrating the reconfiguration of the avionics network of ring communication of the [Fig.l] in case of malfunction of a respective communication node;

[0040] [Fig.5] [Fig.5] is a schematic representation of two avionics networks of ring communication, connected to each other; and

[0041] [Fig.6] [Fig.6] is a schematic representation of a first installation avionics with two interconnected ring avionics communication networks interconnecting avionics equipment such as display screens, electronic computing boards and electronic input / output boards; and respectively a second avionics installation similar to the first installation and where the avionics equipment is further interconnected via a third star communication network.

[0042] In the following description, the expression "approximately equal to" defines a relationship of equality to plus or minus 20%, preferably to plus or minus 10%, and even more preferably to plus or minus 5%.

[0043] In [Fig.1], a civil aircraft 10 includes an avionics installation 12 comprising a ring communication avionics network 15 and avionics equipment 18 interconnected via said network 15.

[0044] The civil aircraft 10 is in particular an airliner, as shown in [Fig. 1]. Alternatively, the civil aircraft 10 is a rotary-wing aircraft, such as a civil helicopter, or a civil drone remotely piloted by a remote operator.

[0045] The avionics communication network 15 is intended to be carried on board the aircraft 10, and comprises at least three communication nodes 20 connected together in the form of a ring, via respective wired data links 22.

[0046] The avionics communication network 15 advantageously consists of said communication nodes 20 and wired links 22 interconnecting said nodes 20.

[0047] Among the nodes 20 of the communication network 15, some nodes 20 are called master nodes and are then denoted 20M, and more specifically 20MA for an active master node, 20MP for a passive master node; and other nodes 20 are called passive nodes and are then denoted 20S, as will be described in more detail later. The reference 20 used for the communication nodes will then generally designate both the master nodes 20MA, 20MP and the slave nodes 20S.

[0048] The communication avionics network 15 comprises at least one active master node 20MA and at least two other nodes 20S, 20MP.

[0049] Each communication node 20 is implemented in the form of an electronic device, and is intended to be connected to a respective avionics equipment 18.

[0050] Each communication node 20 has at least one pair of communication ports Rxl, Txl, Rx2, Tx2, and is directly connected between a previous node 20 and a subsequent node 20 respectively via two separate ports, denoted Rxl, Txl, or Rx2, Tx2 respectively, the communication ports Rxl, Txl, Rx2, Tx2 of two successive nodes 20 of the ring being connected to each other via a wired data link 22. Each pair of communication ports Rxl, Txl, Rx2, Tx2 has a receiver port Rxl, Rx2 configured to receive data from the transmitter port Txl, Tx2 of a previous node 20, and a transmitter port Txl, Tx2 configured to transmit data to the receiver port Rxl, Rx2 of a subsequent node 20.

[0051] As an optional addition, each communication node 20 includes a first pair of communication ports Rxl, Txl and a second pair of communication ports Rx2, Tx2, redundant with the first pair Rxl, Txl. The communication ports Rxl, Txl of the first pairs are successively connected to each other via first data wire links 22A. The communication ports of the second pairs Rx2, Tx2 are successively connected to each other via second data wire links 22B, redundant with the first links 22A. The first pair of communication ports Rxl, Txl is also called the primary pair, and similarly, each first wire link 22A is also called the primary wire link.The second pair of communication ports Rx2, Tx2 is also called the secondary pair, and similarly each second 22B wire link is also called the secondary wire link, the second pair of communication ports Rx2, Tx2 and the associated second 22B wire link(s) being redundant elements respectively of the first pair of communication ports Rxl, Txl and the associated first 22A wire link(s), and used as a secondary when a port of the first pair Rxl, Txl and / or a first 22A wire link used as a primary is malfunctioning, i.e. non-operational, for example out of service, or broken.

[0052] As an optional complement, at least one communication node 20 includes an additional pair of communication ports Rx3, Tx3, visible in [Fig.2], configured to be connected to another communication network 15A, 15B, as shown in the examples in Figures 5 and 6, described in more detail later.

[0053] At least one communication node 20MA includes a sequencing module 25 configured to generate data transport frames 26, each frame 26 circulating in a loop successively from node 20 to node 20. Advantageously, each frame 26 traverses a respective node 20 with a transit time substantially equal to 1 microsecond (ps).

[0054] The at least one communication node comprising the sequencing module 25 is typically a master node, denoted 20MA or 20MP, and preferably a node active master 20MA, the generation of transport frames 26 allowing to perform a sequencing of these frames 26, with a management of the time spacing between frames 26, as will be described below.

[0055] Advantageously, each communication node 20 includes the sequencing module 25, and the sequencing module 25 is then preferably activated for only one of the communication nodes 20, such as the active master node 20MA.

[0056] Each communication node 20 includes a processing module 28 configured to, via the generated frames 26, receive data destined for said avionics equipment 18 from another avionics equipment 18 and / or to send data from said avionics equipment 18 to at least one other avionics equipment 18. In other words, the processing module 28 is configured to, via the frames 26 that pass through the corresponding node 20, read on the fly data destined for said avionics equipment 18 and / or to write on the fly data from said avionics equipment 18 to at least one other avionics equipment 18.

[0057] Advantageously, each communication node 20 includes the sequencing module 25 and the processing module 28, and the sequencing module 25 is then activated for only one of the communication nodes 20, such as the active master node 20MA.

[0058] At least one 20MP communication node includes a monitoring module 30 configured to compare an interframe period to a predefined range of values, a frame anomaly being detected if the interframe period does not fall within said range. The interframe period is the difference between two times when successive frames 26 are received by the 20MP node containing the monitoring module 30. In other words, the monitoring module 30 is configured to verify the correct periodicity of the frames 26.

[0059] At least one communication node comprising the monitoring module 30 is typically a master node, denoted 20MA or 20MP, and preferably a passive master node 20MP, the monitoring being carried out passively, without interaction on the request frame sequence 26.

[0060] Advantageously, each communication node 20 includes the monitoring module 30 and the processing module 28. The monitoring module 30 is then preferentially activated for all communication nodes 20.

[0061] Advantageously, each communication node 20 comprises the sequencing module 25, the monitoring module 30, and the processing module 28. The sequencing module 25 is activated for only one of the communication nodes 20, such as the active master node 20. The monitoring module 30 is then preferentially activated for all communication nodes 20.

[0062] According to this advantageous aspect, not shown, all the communication nodes 20 are preferably physically identical, each node 20 also being called a connection node, allowing an avionics device 18 to be connected to the network. Those skilled in the art will then observe that, although physically identical, these nodes 20 do not all have the same role during the operation of the avionics communication network 15, and in particular that the sequencing module 25 is activated for only one node 20 among all the nodes 20 of the network 15, this node being typically called the master node, the other nodes being called slave nodes.

[0063] This advantageous feature allows for a further reduction in the size of the communication network 15, since it is then unnecessary to have one or more dedicated master nodes. This advantage also improves the reliability of the communication network 15, particularly by offering greater redundancy for the master node, since in the event of a failure of the node acting as the master node, any other node can take over and act as the master node in turn. Typically, in the event of a failure of the node 20 acting as the master node, this node 20 will be isolated from the communication network 15, and another node 20, such as the node following the failed node, will then be configured to assume the new role of master node, by activating the sequencing module 25 for said node 20, which now becomes the master node.

[0064] As an alternative to this advantageous aspect, among the communication nodes 20, two communication nodes 20, called master nodes 20MA, 20MP, each include the sequencing module 25 and the monitoring module 30, as well as the processing module 28. According to this alternative, the sequencing module 25 is then activated for one master node, called the active master node 20MA, and the monitoring module 30 is activated for the other master node, called the passive master node 20MP.

[0065] According to this variant, the nodes 20 other than the master nodes 20MA, 20MP, these other nodes also being called slave nodes 20S, preferentially include only the processing module 28 among the sequencing module 25, monitoring module 30 and processing module 28.

[0066] Each node 20 typically includes an information processing unit formed for example of a memory and a processor associated with the memory, not shown.

[0067] According to this example, the sequencing module 25, the processing module 28, and the monitoring module 30 are implemented, when present in the corresponding node 20, each in the form of a software program, or a software component, executable by the processor. The memory of node 20 is then capable of storing sequencing software, processing software, and monitoring software, as appropriate. The processor is then able to execute each of the software programs, including the sequencing software, the processing software, and the monitoring software.

[0068] In an alternative not shown, the sequencing module 25, the processing module 28 and the monitoring module 30 are implemented, when present in said corresponding node 20, each in the form of a programmable logic component, such as an FPGA (Field Programmable Gate Array), or in the form of a dedicated integrated circuit, such as an ASIC (Application Specified Integrated Circuit).

[0069] When the communication node 20 is implemented as one or more software programs, i.e., as a computer program, it is also capable of being stored on a computer-readable medium (not shown). A computer-readable medium is, for example, a medium capable of storing electronic instructions and being connected to a bus of a computer system. For example, a readable medium is an optical disc, a magneto-optical disc, a ROM, a RAM, any type of non-volatile memory (e.g., EPROM, EEPROM, FLASH, NVRAM), a magnetic card, or an optical card. A computer program comprising software instructions is then stored on the readable medium.

[0070] The sequencing module 25 is configured for example to generate the data transport frames 26 in the form of virtual links VL1, VL2, ..., VLn according to the ARINC 664 Part 7 standard, as shown in [Fig.2].

[0071] According to this optional complement, the sequencing module 25 is then configured to associate a respective interframe gap BAG with each virtual link VL1, VL2, ..., VLn. The interframe gap BAG is a minimum duration between the start times of two successive frames 26 of the corresponding virtual link VL1, VL2, ..., VLn, as shown in [Fig. 3]. In the example in [Fig. 3], a jitter J is represented for each frame 26, the value of the varying jitter J being between a zero value and a maximum value denoted Jmax.

[0072] In the example in [Fig. 2], the interframe gap BAG for each virtual link VL1, VL2, ..., VLn is chosen from a predefined set of values, such as the set containing, for example, the values ​​250 ps (for microsecond), 500 ps, ​​1 ms (for millisecond), 2 ms, 4 ms, 8 ms, 16 ms, 32 ms, 64 ms, and 128 ms. Of course, other BAG interframe gap values ​​are possible, including values ​​lower or higher than those mentioned above.

[0073] The structure of each frame 26, for example, conforms to the ARINC 664 Part 7 standard, and therefore successively comprises the following fields, the description and use of which are described in the ARINC 664 Part 7 standard, represented in [Fig. 3], which corresponds to an extract from the ARINC 664 Part 7 standard, the numbers indicated The codes above the fields correspond to the respective size in byte(s) of each field:

[0074] - PR field, corresponding to a preamble (from the English Preamble),

[0075] - SFD field (Start Frame Delimiter), forming a start indicator plot,

[0076] - DA field (Destination Address), containing a destination address, that is to say, an identifier of the avionics equipment 18 to which the data included in said frame 26 are intended,

[0077] - SA field (from the English Source Address), containing a source address, that is to say- state an identifier of the avionics equipment 18 that emitted the data included in said frame 26,

[0078] - IPv4 field to specify the type of IP protocol,

[0079] - IP Structure field (from the English IP Structure),

[0080] - UDP Struct field (from the English UDP Structure),

[0081] - DPLD field (from the English Data Payload), containing the useful part of the frame 26 corresponding, that is to say the useful data intended for the avionics equipment 18 identified in the DA field,

[0082] - SN field (from the English Serial Number),

[0083] - FCS field (from the English Frame Check Seq), and

[0084] - IFG field (Inter Frame Gap), corresponding to the last field of the frame 26, and being a field left empty, to form a separation with the following frame 26 circulating on the communication network 15.

[0085] The length of the DPLD field forming the useful part of frame 26 is typically variable. Each frame 26 therefore has a variable length, while having a maximum length Lmax corresponding to all the fields from DA to FCS, i.e., all the aforementioned fields except the PR, SFD, and IFG fields. The maximum length Lmax is, for example, equal to 1518 bytes, and frame 26 then has a length of at most 1526 bytes taking into account the PR and SFD fields, and at most 1538 bytes with the additional IFG field.

[0086] Those skilled in the art will further observe that in this example of the structure of [Fig. 3], the SFD, DA, SA, and IPv4 fields, as well as FCS, are managed by the sequencing module 25 during the generation of each respective frame 26. The IP Struct, UDP Struct, and DPLD fields are managed by the node 20 with the right to transmit, i.e., the right to write, on the corresponding frame 26, and in particular by the processing module 28 of said node 20 with the right to transmit.

[0087] As an optional addition, the sequencing module 25 is configured to measure a loopback delay of each respective frame 26 and compare the loopback delay to a predefined range of values, a frame anomaly being detected if the delay loop delay does not belong to said range, the loop delay being the difference between two successive time instants of reception of said frame 26 by the node containing the sequencing module 25. Indeed, the sequencing module 25 receives almost simultaneously the frame it transmits, and can therefore detect an abnormal delay in circulation in the loop formed by the nodes 20.

[0088] The processing module 28 of each node 20 is configured to receive data destined for the avionics equipment 18 associated with said node 20 via the corresponding frame(s) 26 configured for reading and / or to transmit data destined for another piece of equipment 18 via the corresponding frame(s) 26 configured for writing.

[0089] Between two successive nodes 20 of the ring, the first 22A and second 22B wire links are arranged in parallel with each other; and the processing modules 28 of said nodes 20 are configured to circulate the data in a first direction on the first link 22A, and respectively in a second direction, opposite to the first direction, on the second link 22B.

[0090] By way of example, the processing module 28 is configured to, if both ports Rxl and Txl of the first pair are functional, i.e., operational, acquire a frame 26 received on the receiver port Rxl of the first pair, process said frame 26, and then send the processed frame 26 via the transmitter port Txl of the first pair. In this case, that is, if both ports Rxl and Txl of the first pair are functional, the processing module 28 is configured to transfer, without processing, to the transmitter port Tx2 of the second pair, each frame 26 received on the receiver port Rx2 of the second pair.

[0091] According to this example, the transit time of the corresponding node 20 for the primary ring corresponding to the primary links 22A, that is, the time taken by a respective frame 26 between its reception on the receiving port Rxl and its transmission via the transmitting port Txl, is typically on the order of 1 ps (microsecond). The transit time of the corresponding node 20 for the corresponding secondary ring corresponding to the secondary links 22B, that is, the time taken by a respective frame 26 to be transferred without processing from the receiving port Rx2 or transmitting port Tx2, is typically much less than 1 ps, for example on the order of 0.1 ps.

[0092] As an optional complement, the processing module 28 is configured to, if the receiver port Rxl of the first pair is malfunctioning, i.e. non-operational, acquire a frame 26 received on the receiver port Rx2 of the second pair, to process said frame 26, and then to send the processed frame 26 via the transmitter port Txl of the first pair.

[0093] As a further optional feature, the processing module 28 is configured so that, if the Txl transmitter port of the first pair is malfunctioning, i.e., non-operational, acquire a frame 26 received on the receiver port Rxl of the first pair, to process said frame 26, then to send the processed frame 26 via the transmitter port Tx2 of the second pair.

[0094] A person skilled in the art will understand that by processing frame 26, we mean reading data from frame 26 and / or writing data from frame 26.

[0095] This mechanism implemented by the processing module 28 is also called the loopback mechanism, denoted LBM (Loop Back Mechanism) in [Fig. 2], and thus maintains a link loop between operational nodes 20 to form the ring communication network 15 with the nodes 20 remaining operational, even in the event of a malfunction of a failed node 20. This is shown in [Fig. 4], where the failed node 20 is crossed out, and the other remaining operational nodes 20 are then connected to each other via the loop corresponding to the bold arrows.

[0096] In the example of [Fig. 4], when a node 20 is completely down, the loop is maintained between the remaining operational nodes 20 by implementing this loopback mechanism for the two nodes 20 located on either side of the failed node 20. More precisely, the node 20 located upstream of the failed node 20, following the direction of frame 26 flow on the primary links 22A, being unable to send frames to the failed node 20 via the transmitting port Tx1 of its first pair, will then send these frames 26 via the transmitting port Tx2 of the second pair, that is, on the secondary link 22B connected to this transmitting port Tx2, and thus in the opposite direction to the direction of frame 26 flow on the primary links 22A.For node 20 located downstream of the failing node 20, following the direction of frame 26 flow on the primary links 22A, the frames 26 will then circulate on the secondary links 22B, due to the loopback mechanism implemented on the upstream node, as described above, and this downstream node, unable to send the frames 26 to the failing node 20 via the transmitting port Tx2 of its second pair, will then send them via the transmitting port Txl of its first pair, that is to say on the primary link 22A connected to this transmitting port Txl, and therefore in the direction of frame 26 flow on the primary links 22A, also called direct send, and therefore again towards the upstream node.

[0097] With this LBM loopback mechanism, the ring communication network 15 according to the invention remains operational even in the event of a failure of one of its communication nodes 20.

[0098] The person skilled in the art will observe that the dashed arrows inside the nodes 20 in Figures 1, 2, 4 and 5 represent the possible link derivations resulting from this LBM looping mechanism.

[0099] According to another optional complement, for each data transport frame 26, the processing module 28 of a single respective node 20 is authorized to write data into said frame 26 for sending data to one or more of the other equipment 18, and the processing modules 28 of all other nodes 20 are only authorized to read data from said frame 26. In other words, according to this optional complement, a single respective node 20 has write rights in said frame 26.

[0100] As an optional additional step, the data to be transmitted by a respective avionics device 18 is positioned by the corresponding processing module 28 in a virtual sub-link (SVL), visible in [Fig. 2], potentially several frames 26 at a time. The frames 26 positioned in the virtual sub-links are then positioned by the corresponding processing module 28 in the associated virtual link (VL), by processing the frames in the virtual sub-links one by one. This mechanism, called round-tripping, illustrated by the RT arrows in [Fig. 2], prevents the transmission of a small frame from being delayed by a large stream of frames 26.

[0101] In addition, the processing module 28 is configured to implement a frame pickup mechanism for frames 26 contained in the virtual links VL1, VL2, ..., VLn when the frame(s) 26 having the header of a corresponding virtual link VL1, VL2, ..., VLn pass through the node 20 containing said processing module 28.

[0102] A person skilled in the art will more generally observe that each processing module 28 is configured to perform on-the-fly processing of frames 26 passing through the node 20 corresponding to said processing module 28.

[0103] When at least one communication node 20 has the additional pair of communication ports Rx3, Tx3, and preferably when two communication nodes 20, such as the two master nodes 20MA, 20MP, each have the additional pair of communication ports Rx3, Tx3, the ring communication avionics network 15 according to the invention is then able to be interconnected with another communication network, and for example with another ring communication network 15 according to the invention, as shown in [Fig.5].

[0104] In the example of [Fig. 5], a first ring communication network 15A is interconnected with a second ring communication network 15B. In this example, each network 15A, 15B comprises both an active master node 20A and a passive master node 20B, each having the additional pair of communication ports Rx3, Tx3. The interconnection between the first and second networks 15A, 15B is then achieved by connecting the active master node 20MA of one network 15A, 15B to the passive master node 20MP of the other network 15B, 15A, via their additional pairs of communication ports Rx3, Tx3 and the third wired links 22C connecting each time a transmitter port Tx3 to a receiver port Rx3. The interconnection data flows are declared in the two sequencing modules 25 of the two networks 15A, 15B, so that the data flows entering a network 15A, 15B by a transmitter port Tx3 are inserted by copy at the time when the frame 26 having the same identifier circulates on said network 15A, 15B.

[0105] In terms of availability and fault tolerance, two ring communication networks 15A, 15B according to the invention connected together are equivalent to a four-switched star topology, conforming to ARINC 664 Part 7.

[0106] This architecture with two interconnected ring communication networks 15A, 15B according to the invention is illustrated in two implementation examples in [Fig.6],

[0107] According to a first example, a first IT1 installation comprises six DPI display screens, DP2, DP3, DP4, DP5, DP6, four CPU1, CPU2, CPU3, CPU4 computing boards, and four IOM1, IOM2, IOM3, IOM4 input / output boards. Each of these screens, computing boards, or input / output boards forms an avionics unit 18 and is associated with a respective communication node 20. In this example, the communication node 20 is integrated into the respective avionics unit 18 to which it is associated. The first IT1 installation also includes three SI sensors, S2, S3, connected to the IOM1, IOM2, IOM3, IOM4 input / output boards.

[0108] In the first example of [Fig. 6], three DPI display screens, DP2, DP5, two CPU1, CPU2 computing boards, and two IOM1, IOM2 input / output boards are interconnected via the first ring communication network 15A; and the three other display screens, DP3, DP4, DP6, the two other CPU3, CPU4 computing boards, and the two other IOM3, IOM4 input / output boards are interconnected via the second ring communication network 15B. The interconnection between the first and second communication networks 15A, 15B is then, for example, carried out via the communication nodes 20 integrated into the four CPU1, CPU2, CPU3, CPU4 computing boards, these nodes 20 forming the two master nodes, active 20MA and passive 20MP respectively.

[0109] According to a second embodiment shown in [Fig. 6], a second IT2 installation comprises the same avionics equipment 18 as the first IT1 installation and the first and second communication networks 15A, 15B interconnected as in the first IT1 installation

[0110] According to this second example, the second IT2 installation further comprises an additional star-shaped communication network 40 with switches 42 and associated wired links 44 allowing the interconnection of said avionics equipment 18, i.e. the six display screens DPI, DP2, DP3, DP4, DP5, DP6, four electronic computing boards CPU1, CPU2, CPU3, CPU4 and four electronic input-output boards IOM1, IOM2, IOM3, IOM4, in addition according to a star topology.

[0111] This hybrid architecture according to the second example with, on the one hand, the first and second communication networks 15A, 15B according to the invention, and on the other hand, the additional communication network 40 in star with switches 42 according to the prior art then makes it possible to achieve a high level of architectural dissimilarity to offer even better availability and fault tolerance.

[0112] Thus, the ring-shaped avionics communication network 15 according to the invention forms a switchless network with a loop topology having an availability equivalent to a prior art network conforming to ARINC 664 Part 7, while providing the following improvements over this prior art network:

[0113] - an integrity superior to the prior art network, through monitoring carried out by the monitoring module 30, including the detection of the failure case corresponding to an abnormal delay in the transmission of a frame 26;

[0114] - improved performance in terms of jigging, particularly due to the absence of switch, allowing to extend the field of use of the communication network 15 according to the invention, by allowing data flows with very low jitter on the order of microseconds;

[0115] - a determinism by nature allowing for considerable simplification of the qualification of the communication network 15 according to the invention, and making possible an incremental qualification of said network 15;

[0116] - the ability to synchronize avionics equipment 18 interconnected via said communication network 15 according to the invention, with synchronization on the order of the microsecond.

[0117] In addition, the size, mass and consumption, or SWaP, of the avionics communication network 15 according to the invention, as well as its cost, are significantly improved compared to the prior art network, with the elimination of switches and the reduction of cabling.

[0118] The performance of the communication network 15 according to the invention is also improved by means of deterministic programming of the communication flows allowing control thereof and achieving for the data flows which require it a jitter of the order of the microsecond.

[0119] Determinism and incremental qualification of the communication network 15 according to the invention are obtained through deterministic flow programming communication, through the generation of data transport frames 26 at regular time intervals, for example in the form of virtual links, serving as vectors, or "vehicles", for the transport of this data.

[0120] Furthermore, unlike some prior art communication networks implementing an arbitration protocol, the avionics communication network 15 according to the invention does not require an arbitration protocol since only one of the communication nodes is allowed to generate transport frames at a given time and there is therefore no risk of collision between frames.

[0121] It is thus understood that the avionics communication network 15 according to the invention is improved compared to the prior art network.

Claims

Demands

1. A ring-shaped avionics communication network (15) for installation on board a civil aircraft (10) comprising at least three interconnected communication nodes (20) in a ring, each communication node (20, 20MA, 20MP, 20S) having at least one pair of communication ports (Rxl, Txl; Rx2, Tx2) and being directly connected between a preceding and a following node (20) respectively via two separate ports (Rxl, Txl; Rx2, Tx2) respectively, the communication ports (Rxl, Txl; Rx2, Tx2) of two successive nodes (20) in the ring being interconnected via a wired data link (22), at least one communication node (20MA) having a sequencing module (25) configured to generate data transport frames (26), each frame (26) circulating in a loop successively from node (20) in node (20), each communication node (20, 20MA, 20MP,20S) being intended to be connected to a respective avionics equipment (18) and comprising a processing module (28) configured to, via the generated frames (26), receive data destined for said avionics equipment (18) from another avionics equipment (18) and / or to send data from said avionics equipment (18) to at least one other avionics equipment (18), at a given time, only one of the communication nodes (20) being configured to generate the data transport frames (26), the sequencing module (25) being activated for only one of the communication nodes (20) at a time.

2. Network (15) according to claim 1, wherein each communication node (20) comprises the sequencing module (25) and the processing module (28).

3. Network (15) according to claim 1 or 2, wherein at least one communication node (20MP) comprises a monitoring module (30) configured to compare an inter-frame period to a predefined range of values, a frame anomaly being detected if the inter-frame period does not belong to said range, the inter-frame period being the difference between two time instants reception of successive frames (26) by the node comprising the monitoring module (30); each communication node (20) preferably comprising the monitoring module (30) and the processing module (28); the monitoring module (30) preferably still being activated for all communication nodes (20).

4. Network (15) according to claims 2 and 3, wherein each communication node (20) comprises the sequencing module (25), the monitoring module (30) and the processing module (28); the monitoring module (30) preferably being activated for all communication nodes (20).

5. Network (15) according to any one of claims 1 to 3, wherein among the communication nodes (20), two communication nodes (20), referred to as master nodes (20MA, 20MP), each comprise the sequencing module (25) and the monitoring module (30), the sequencing module (25) being activated for one master node, referred to as the active master node (20MA), and the monitoring module (30) being activated for the other master node, referred to as the passive master node (20MP); the communication nodes, referred to as slave nodes (20S), other than the master nodes (20MA, 20MP) preferably comprising only the processing module (28) among the sequencing (25), monitoring (30) and processing (28) modules.

6. Network (15) according to any one of the preceding claims, wherein each communication node (20, 20MA, 20MP, 20S) comprises a first pair of communication ports (Rxl, Txl) and a second pair of communication ports (Rx2, Tx2), redundant with the first pair (Rxl, Txl); the communication ports (Rxl, Txl) of the first pairs being successively connected to each other via first wired data links (22A), and the communication ports of the second pairs (Rx2, Tx2) being successively connected to each other via second wired data links (22B), redundant with the first links (22A).

7. Network (15) according to claim 6, wherein between two successive nodes (20) of the ring, the first (22A) and second (22B) wired links are arranged in parallel with each other; and the processing modules (28) of said nodes (20) are configured to circulate the data in a first direction on the first link (22A), and respectively in a second direction, opposite to the first direction, on the second link (22B).

8. Network (15) according to claim 6 or 7, wherein each pair of ports (Rxl, Txl; Rx2, Tx2) has a receiving port (Rxl, Rx2) and a transmitting port (Txl, Tx2); and - if both ports (Rxl, Txl) of the first pair are functional, the processing module (28) is configured to acquire a frame (26) received on the receiving port (Rxl) of the first pair, to process said frame (26), and then to send the processed frame (26) via the transmitting port (Txl) of the first pair; and the processing module (28) is configured to forward, without processing, to the transmitting port (Tx2) of the second pair, each frame (26) received on the receiving port (Rx2) of the second pair;- if the receiving port (Rxl) of the first pair is malfunctioning, the processing module (28) is configured to acquire a frame (26) received on the receiving port (Rx2) of the second pair, to process said frame (26), and then to send the processed frame (26) via the transmitting port (Txl) of the first pair; and - if the transmitting port (Txl) of the first pair is malfunctioning, the processing module (28) is configured to acquire a frame (26) received on the receiving port (Rxl) of the first pair, to process said frame (26), and then to send the processed frame (26) via the transmitting port (Tx2) of the second pair.

9. Network (15) according to any one of the preceding claims, wherein at least one communication node (20) has an additional pair of communication ports (Rx3, Tx3) configured to be connected to another communication network (15A; 15B).

10. Network (15) according to any one of the preceding claims, wherein the sequencing module (25) is configured to generate data transport frames (26) in the form of virtual links (VL1, VL2, ..., VLn) according to ARINC 664 Part 7, and to associate a respective interframe gap (BAG) with each virtual link (VL1, VL2, ..., VLn), the interframe gap (BAG) being a minimum duration between start times of two successive frames (26) of the corresponding virtual link (VL1, VL2, ..., VLn).

11. Network (15) according to any one of the preceding claims, wherein for each data transport frame (26), the

12. processing module (28) of a single respective node (20) is permitted to write data into said frame (26) for sending data to one or more of the other equipment (18), and the processing modules (28) of all other nodes (20) are permitted only to read data from said frame (26). Civil aircraft (10) comprising a ring-shaped avionics communication network (15) according to any one of the preceding claims and avionics equipment (18) interconnected via said network (15).

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