CN112887180A - Communication method of bus type real-time Ethernet - Google Patents
Communication method of bus type real-time Ethernet Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
- H04L12/40006—Architecture of a communication node
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
- H04L69/30—Definitions, standards or architectural aspects of layered protocol stacks
- H04L69/32—Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
- H04L69/322—Intralayer communication protocols among peer entities or protocol data unit [PDU] definitions
- H04L69/327—Intralayer communication protocols among peer entities or protocol data unit [PDU] definitions in the session layer [OSI layer 5]
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Abstract
The invention provides a communication method of a bus type real-time Ethernet, which is provided with a plurality of nodes which are equal and are mutually connected in communication, each node is provided with a data link layer for data transmission, and the transmitted data comprises periodic data and random data, and the communication method is characterized in that: the data link layer of each node is provided with a session layer which is used for coordinating and controlling data transmission between the nodes, the session layer divides communication time into communication cycles with equal duration and cyclic repetition, each communication cycle comprises a static segment, a dynamic segment and an NIT segment which are sequentially arranged, the static segment is divided into a plurality of time slots with equal duration and different numbers and used for transmitting periodic data, the dynamic segment is used for transmitting random data, the NIT segment is the ending stage of the communication cycle and used for clock synchronization, and all the nodes in the NIT segment do not transmit data.
Description
Technical Field
The invention relates to an Ethernet communication method, in particular to a bus type real-time Ethernet communication method.
Background
The traditional Ethernet (Ethernet) is a local area Ethernet communication technology which is currently most widely used, and has been the most successful network technology through the development of more than 40 years, and has led to an information technology revolution, and as the metropolitan area Ethernet forum (MEF) continues to apply the Ethernet technology to the construction of metropolitan area networks as a switching technology and a transmission technology, the Ethernet has not only been limited to the local area network application, but also can be more widely applied to the fields of Metropolitan Area Networks (MANs) and Wide Area Networks (WANs).
The media access control strategy of the conventional Ethernet (Ethernet) is CSMA/cd (carrier Sense multiple access with Collision detection), i.e. carrier Sense multiple access/Collision detection. When two or more nodes transmit information simultaneously, a collision occurs and a solution to the collision must be found. CSMA/CD resolves collisions by performing carrier sensing, sensing while transmitting, enforcing collision, and collision back-off algorithms before transmitting information. This method can successfully transmit information through a bus (communication channel) only if no collision occurs. Obviously, such a non-deterministic scheduling method may cause a large delay of the message during the peak period of the load, and even affect the timely transmission of the information of the key device. Thus, the behavior of the system is not deterministic.
However, ethernet itself has many advantages, such as high bandwidth, low cost, scalability, etc., and it is these advantages that researchers are not willing to give up it because of its communication uncertainty, so improving the communication mode of ethernet, enabling ethernet to realize real-time determined communication, and improving its real-time, certainty and communication reliability has become one of the urgent needs of ethernet development at present.
Disclosure of Invention
The present invention has been made to solve the above problems, and an object of the present invention is to provide a communication method for a bus-type real-time ethernet network.
The invention provides a communication method of a bus type real-time Ethernet, which is provided with a plurality of nodes which are equal and are mutually connected in communication, each node is provided with a data link layer for data transmission, and the transmitted data comprises periodic data and random data, and the communication method is characterized in that: a session layer is arranged on a data link layer of each node, the session layer is used for coordinating and controlling data transmission between the nodes, the session layer divides communication time into communication cycles with equal duration and repeated cycle, each communication cycle comprises a static section, a dynamic section and an NIT section which are arranged in sequence, the static section is divided into a plurality of time slots with equal duration and different numbers and used for transmitting periodic data, the dynamic section is used for transmitting random data, the NIT section is the end stage of the communication cycle and used for clock synchronization, each node in the NIT section does not transmit data, each time slot corresponds to a designated node or designated periodic data by the number, when the node or the periodic data needs to be transmitted at regular time, the data transmission is carried out in the corresponding time slot, the tail section of the dynamic section is provided with a guard band, in the guard band, the transmission of a new frame is not allowed to start, but the frame in transmission can be continuously sent, and a frame cutting method is adopted in the dynamic segment: once the random data can not be completely sent in the current dynamic segment, frame slicing is carried out on the random data by adopting a frame cutting method, a check code is supplemented to verify the correctness of data transmission, the rest frame slices are transmitted at the beginning of the dynamic segment of the next communication cycle, schedulable communication is adopted for the periodic data, and unscheduled communication is adopted for the random data.
The communication method of the bus type real-time Ethernet provided by the invention can also have the following characteristics: the static section adopts TDMA mode to control data transmission, and the dynamic section adopts CSMA/CD protocol to control data transmission.
The communication method of the bus type real-time Ethernet provided by the invention can also have the following characteristics: the session layer records the number of the time slot, the start and stop time, and the node or periodic data corresponding to each time slot.
The communication method of the bus type real-time Ethernet provided by the invention can also have the following characteristics: wherein, the session layer is also used for recording the frame slice size and transmitting and receiving the rest frame slices.
Action and Effect of the invention
According to the communication method of the bus type real-time Ethernet, a session layer is additionally arranged on a data link layer, the session layer divides communication time into communication cycles with equal duration and repeated cycle, each communication cycle is provided with a static segment, the static segments comprise a plurality of time slots with different numbers and corresponding to nodes or periodic data one by one, and when the nodes or the periodic data need to be transmitted at regular time, data transmission is carried out in the corresponding time slots, so that each node can ensure the transmission completion of the real-time data, the Ethernet realizes the communication with time certainty and can be applied to a network environment with real-time communication requirements; the dynamic segment adopts CSMA/CD to transmit random data and can be compatible with an IEEE802.3 protocol, so that the application range of the invention is wider; in addition, a protective band is arranged in the dynamic section, and the integrity and the real-time performance of periodic data transmission are guaranteed by adopting a frame cutting method; the invention carries out coordination control by adding the session layer without changing the data link layer and the physical layer of the Ethernet, thereby not only being compatible with the IEEE802.3 protocol, but also being compatible with protocols such as TCP/IP and the like, and having wide application range.
Drawings
FIG. 1 is a schematic diagram of a comparison of the ISO/OSI, conventional Ethernet and bus-type real-time Ethernet configurations in an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a bus-type real-time ethernet network used in the communication method according to the embodiment of the present invention;
FIG. 3 is a schematic diagram of a communication cycle in an embodiment of the invention;
FIG. 4 is a schematic diagram of a slot structure in an embodiment of the invention;
FIG. 5 is a schematic diagram of a dynamic segment in an embodiment of the invention.
Detailed Description
In order to make the technical means and functions of the present invention easy to understand, the present invention is specifically described below with reference to the embodiments and the accompanying drawings.
< example >
FIG. 1 is a reference and comparison diagram of ISO/OSI, conventional Ethernet and bus-type real-time Ethernet configurations in an embodiment of the present invention.
As shown in fig. 1, the Open System Interconnection (OSI) reference model established by the international organization for standardization (ISO) is divided into 7 layers, namely, an application layer, a presentation layer, a session layer, a transport layer, a network layer, a data link layer, and a physical layer in sequence from top to bottom.
Traditional ethernet only defines the lowest two layers of the model: the physical layer and the data link layer.
While the real-time ethernet protocol of the present embodiment is mainly located at the session layer above the data link layer, the protocol layer formed by the real-time ethernet over the conventional ethernet does not change the structure of the data link layer and the physical layer of the conventional ethernet in any way.
The physical layer serves as a transmission medium for bit encoding and decoding, bit timing and synchronization.
The data Link layer mainly includes a Logical Link Control (LLC) sub-layer and a Media Access Control (MAC) sub-layer.
The logical link control sublayer LLC is used for receiving filtering, receiving and transmitting overload notifications and performing recovery management, and the media intervention control sublayer MAC is used for performing data encapsulation/disassembly, frame coding, media access management, and the like.
The session layer is located above the data link layer and is used for performing coordination control in the data transmission process between the nodes.
Fig. 2 is a schematic structural diagram of a bus-type real-time ethernet network used in the communication method according to the embodiment of the present invention.
As shown in fig. 2, a communication method of a bus-type real-time ethernet of the present embodiment includes a plurality of nodes that are equal and communicatively connected to each other, each node having a data link layer for data transmission, where the transmitted data includes periodic data and random data: a session layer is arranged on the data link layer of each node and used for coordinating data transmission among the control nodes, and the session layer divides communication time into communication cycles with equal duration and cyclic repetition.
Fig. 3 is a schematic diagram of a communication loop in an embodiment of the invention.
As shown in fig. 3, each communication cycle includes a static segment, a dynamic segment, and an NIT segment, which are sequentially arranged.
The static section is divided into a plurality of time slots with equal time length and different numbers and is used for transmitting periodic data, the static section adopts a TDMA mode to control data transmission and is used for schedulable communication, and the periodic data adopts schedulable communication.
The dynamic segment is used for transmitting random data, the dynamic segment adopts CSMA/CD protocol to control data transmission and is used for unscheduled communication, and the random data adopts unscheduled communication.
The NIT section is the end stage of the communication cycle and is used for clock synchronization, and all nodes in the NIT section do not transmit data.
When the bus type real-time Ethernet carries out system configuration, the time among all nodes is synchronized in advance, so that the starting time of each communication cycle is derived from a trigger signal of a synchronous time base.
FIG. 4 is a schematic diagram of a slot structure in an embodiment of the invention;
as shown in fig. 4, the static segment is divided into n slots (i.e. slots) with the same duration, and the number of the slots is different, so that the number of each slot is unique, and the slots are sorted according to time, and the numbers are slot 1-slot n respectively. And the duration, start time and end time of each slot are set at the system configuration. Each time slot corresponds to a designated node or designated periodic data through the number, and when the node or the periodic data needs to be transmitted at regular time, the data transmission is carried out in the corresponding time slot. For example, when a node has a need for timing transmission, it is assigned a certain numbered slot at the system configuration, and the session layer of the node makes it start the transmission of timing data at the beginning of the slot and stops it at the end of the slot.
The session layer records the number of the time slot, the start and stop time and the node or periodic data corresponding to each time slot.
FIG. 5 is a schematic diagram of a dynamic segment in an embodiment of the invention.
As shown in fig. 5, the end segment of the dynamic segment is provided with a guard band in which transmission of a new frame is not allowed to start, but transmission of a frame in progress can be continued.
In this embodiment, the dynamic segment is compatible with the IEEE802.3 protocol, so the CSMA/CD protocol is used as the medium access control policy, and obviously, after data collision occurs, it is not determined whether the frame can be completely transmitted in the dynamic segment of the current communication cycle through a back-off algorithm, and therefore, the static segment of the next communication cycle may be occupied, so that transmission of real-time data is delayed or cannot be transmitted. In this case, in order to protect the static segment of the next communication cycle from interference, the length of the guard band needs to cover the time taken by the maximum frame transmission, obviously, too long guard band causes a large waste of bandwidth, so a frame cutting method is adopted in the dynamic segment on the basis: once the random data can not be completely sent in the current dynamic segment, frame slicing is carried out on the random data by adopting a frame cutting method, a check code is supplemented to verify the correctness of data transmission, and the rest frame slices are transmitted at the beginning of the dynamic segment of the next communication cycle.
In this embodiment, the setting process of the length of the guard band under the frame cutting method is specifically as follows: the ethernet frame is limited by the transmission of 64 bytes, so it must be ensured that neither slice (containing the check code) after slicing is smaller than 64 bytes, wherein the transmitted part needs at least 60 bytes, 1 mCRC of 4 bytes is separately supplemented on the slice after slicing, the slice needing to wait for the next transmission needs at least the remaining 64 bytes, and the remaining slice already contains the check code, that is, the ethernet frame cannot be sliced when the size is smaller than 124 bytes. At this point, the length of the guard band can be reduced significantly to 128 bytes: 64 bytes (minimum frame) +64 bytes (remaining length that cannot be sliced).
The session layer is also used to record the frame slice size and transceive the remaining frame slices.
Effects and effects of the embodiments
According to the communication method of the bus type real-time Ethernet related by the embodiment, a session layer is additionally arranged on a data link layer, the session layer divides communication time into communication cycles with equal duration and repeated cycle, each communication cycle is provided with a static segment, the static segment comprises a plurality of time slots with different numbers and corresponding to nodes or periodic data one by one, and when the nodes or the periodic data need to be transmitted at regular time, data transmission is carried out in the corresponding time slots, so that each node can ensure the transmission completion of the real-time data, the Ethernet realizes the communication with time certainty, and the communication method can be applied to a network environment with real-time communication requirements; the dynamic segment adopts CSMA/CD to transmit random data and can be compatible with an IEEE802.3 protocol, so that the application range of the invention is wider; in addition, a protective band is arranged in the dynamic section, and the integrity and the real-time performance of periodic data transmission are guaranteed by adopting a frame cutting method; the invention carries out coordination control by adding the session layer without changing the data link layer and the physical layer of the Ethernet, thereby not only being compatible with the IEEE802.3 protocol, but also being compatible with protocols such as TCP/IP and the like, and having wide application range.
The above embodiments are preferred examples of the present invention, and are not intended to limit the scope of the present invention.
Claims (4)
1. A communication method of a bus type real-time ethernet network having a plurality of equal and communicatively interconnected nodes, each of said nodes having a data link layer for data transmission, the transmitted data including periodic data and random data, characterized in that:
a session layer is arranged on the data link layer of each node and used for coordinating and controlling data transmission among the nodes,
the session layer divides the communication time into communication cycles with equal duration and repeated cycle by cycle, each communication cycle comprises a static segment, a dynamic segment and an NIT segment which are arranged in sequence,
the static segment is divided into a plurality of time slots with equal duration but different numbers for transmitting the periodic data,
the dynamic segment is used for transmitting the random data,
the NIT section is the ending stage of the communication cycle and is used for clock synchronization, each node in the NIT section does not carry out data transmission,
wherein each time slot corresponds to one appointed node or appointed periodic data through the number, when the node or the periodic data needs to be transmitted at regular time, the data transmission is carried out in the corresponding time slot,
the end of the dynamic segment is provided with a guard band in which transmission of a new frame is not allowed to start, but transmission of the frame being transmitted can continue,
the dynamic segment adopts a frame cutting method: once the random data can not be completely sent in the current dynamic segment, the random data is subjected to frame slicing by adopting the frame slicing method, a check code is supplemented to verify the correctness of data transmission, the rest frame slices are transmitted at the beginning of the dynamic segment of the next communication cycle,
the periodic data adopts schedulable communication, and the random data adopts non-scheduling communication.
2. The communication method of the bus type real-time ethernet according to claim 1, wherein:
wherein the static segment controls data transmission in a TDMA manner,
and the dynamic segment controls data transmission by adopting a CSMA/CD protocol.
3. The communication method of the bus type real-time ethernet according to claim 1, wherein:
the session layer records the number of the time slot, the start and stop time, and the node or the periodic data corresponding to each time slot.
4. The communication method of the bus type real-time ethernet according to claim 1, wherein:
wherein the session layer is further configured to record the frame slice size and transceive the remaining frame slices.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5960001A (en) * | 1997-06-19 | 1999-09-28 | Siemens Information And Communication Networks, Inc. | Apparatus and method for guaranteeing isochronous data flow on a CSMA/CD network |
| CN102035706A (en) * | 2010-11-29 | 2011-04-27 | 浙江大学 | Method for carrying out communication capacity expansion on static segment of vehicle-mounted electronics bus |
| CN103873387A (en) * | 2014-03-11 | 2014-06-18 | 重庆邮电大学 | Industrial Ethernet-oriented deterministic communication scheduling method |
| CN106603364A (en) * | 2017-01-06 | 2017-04-26 | 上海理工大学 | Ethernet communication method for real-time transmission |
| CN106686046A (en) * | 2016-07-13 | 2017-05-17 | 湖南宏迅亿安新能源科技有限公司 | Vehicle-mounted FlexRay bus network static segment signal design method and device |
| CN110289929A (en) * | 2019-06-12 | 2019-09-27 | 上海理工大学 | A kind of network synchronization method |
| CN110943899A (en) * | 2019-12-13 | 2020-03-31 | 重庆邮电大学 | EPA industrial bus and time sensitive network adaptation system and method |
| CN111147514A (en) * | 2019-12-31 | 2020-05-12 | 上海理工大学 | Communication frame suitable for real-time Ethernet session layer and design method |
-
2021
- 2021-01-28 CN CN202110118116.5A patent/CN112887180A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5960001A (en) * | 1997-06-19 | 1999-09-28 | Siemens Information And Communication Networks, Inc. | Apparatus and method for guaranteeing isochronous data flow on a CSMA/CD network |
| CN102035706A (en) * | 2010-11-29 | 2011-04-27 | 浙江大学 | Method for carrying out communication capacity expansion on static segment of vehicle-mounted electronics bus |
| CN103873387A (en) * | 2014-03-11 | 2014-06-18 | 重庆邮电大学 | Industrial Ethernet-oriented deterministic communication scheduling method |
| CN106686046A (en) * | 2016-07-13 | 2017-05-17 | 湖南宏迅亿安新能源科技有限公司 | Vehicle-mounted FlexRay bus network static segment signal design method and device |
| CN106603364A (en) * | 2017-01-06 | 2017-04-26 | 上海理工大学 | Ethernet communication method for real-time transmission |
| CN110289929A (en) * | 2019-06-12 | 2019-09-27 | 上海理工大学 | A kind of network synchronization method |
| CN110943899A (en) * | 2019-12-13 | 2020-03-31 | 重庆邮电大学 | EPA industrial bus and time sensitive network adaptation system and method |
| CN111147514A (en) * | 2019-12-31 | 2020-05-12 | 上海理工大学 | Communication frame suitable for real-time Ethernet session layer and design method |
Non-Patent Citations (1)
| Title |
|---|
| 王国意等: "以太网上的多媒体传输", 《计算机研究与发展》 * |
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