WO2010025628A1

WO2010025628A1 - Method, equipment and system for data transmission on physical layer.

Info

Publication number: WO2010025628A1
Application number: PCT/CN2009/071907
Authority: WO
Inventors: 董卉慎; 肖瑞杰
Original assignee: 华为技术有限公司
Priority date: 2008-09-05
Filing date: 2009-05-21
Publication date: 2010-03-11
Also published as: CN101667959A; CN101667959B

Abstract

A method, equipment and system for data transmission on the physical layer. The method includes that a physical layer side receives data transmitted in-band from a link layer side, wherein, a media independent interface being adopted between the physical layer side and the link layer side for in-band transmission of data; when the physical layer side needs to flow-control the link layer side, the physical layer side generates a back pressure signal and transmits it to the link layer side through a back pressure signal line in order to make the link layer side respond the back pressure signal for flow-controlling the data transmitted to the physical layer side.

Description

A method, device and system for transmitting physical layer data. The present application claims a system, method and device for data transmission, which is filed on September 5, 2008, with the application number of 200810214351.7. Priority of the Chinese application, the entire contents of which are incorporated herein by reference.

Technical field

The present invention relates to the field of communications technologies, and in particular, to a method, device, and system for physical layer data transmission. Background technique

In the IP service field, there are multiple transmission protocols between the physical layer (PHY, Physical Layer) and the link layer. In order to be compatible with multiple protocols, there are usually multiple interfaces between physical layer devices and link layer devices. This method of using different interfaces for data transmission according to different protocols requires a foreign address, and the chip pins are configured according to the corresponding transmission protocol. When performing multi-line parallel transmission, the number of pins of the chip must be increased, which makes the chip The cost increases, and the bandwidth of multiple lines sharing the bus will limit the effective bandwidth of each line.

For the way of using different interfaces for data transmission according to different protocols, the prior art proposes a serial high-speed bus method for data transmission. In this serial mode, data, address and flow control signals are adopted. In-band mode transmission, in the transmission process, the data using different protocols is no longer distinguished, and the data is encapsulated and transmitted in the form of Ethernet. Using a unified interface for data transmission can reduce the type of interface and reduce the complexity of the interface. By using the in-band address and transmitting the line address in the in-band mode, the line port can be distinguished. When the line is increased, there is no need to increase the chip. The number of pins reduces the number of pins on the chip.

As shown in FIG. 1, the data unit and the flow control signal PAUSE frame are outputted to the serial interface through the data selector. For the data unit, when transmitting data from the PHY side to the Link side, the data unit (format can be an Ethernet frame, an ATM cell) is encapsulated into an Ethernet frame, and then the destination address is added at the frame header, that is, the media access control on the link side. (MAC, Media Access Control) address, source address (PHY side MAC address), finally add the network identifier at the very front end of the entire data, thus completing the data encapsulation. When transferring data from the Link side to the PHY side, the encapsulation is similar to the above, and only the destination address is exchanged with the source address.

Flow Control Signal The PAUSE frame is used to control the data transmission from the Link side to the PHY side. The PAUSE frame is only transmitted from the PHY side to the Link side. When a request needs to be sent, a destination address (Link side MAC address) and a source address (PHY side MAC address) are added at the front end of the request message, and a cyclic redundancy check code CRC check value is added at the end of the data to form a PAUSE frame data.

In the process of implementing the present invention, the inventors have found that at least such a problem exists in the prior art: Since the in-band and serial transmission modes are adopted, the PAUSE frame mode is used for flow control, and the physical layer of the flow control frame is first initiated. The device needs to generate a PAUSE frame. After receiving the PAUSE frame, the peer link layer device needs to parse before responding to the flow control. Meanwhile, if the currently transmitted data packet is large, the PAUSE frame must wait until the data packet is transmitted. After the completion, it can be inserted into the transmission queue and transmitted, which will make the real-time performance of the flow control frame not strong, and the flow control response will be delayed. Summary of the invention

In view of this, the present invention provides a method, device and system for physical layer data transmission, which can reduce the flow control response lag and improve the real-time performance of the flow control signal.

To achieve the above objective, the embodiment of the present invention is implemented by the following technical solutions:

In one aspect, a method for data transmission of a physical layer is provided, including: receiving, by the physical layer side, in-band transmission data sent by a link layer side, where the physical layer side and the link layer side are respectively performed by using a medium independent interface. In-band transmission of data; when the physical layer side needs to flow control on the link layer side, the physical layer side generates a back pressure signal and transmits the back pressure signal to the link layer side through the back pressure signal line, so that the link The layer side controls the data sent to the physical layer side in response to the back pressure signal.

In another aspect, an apparatus for providing physical layer data transmission includes: a data transmission unit, configured to receive in-band transmission data sent by a link layer side, where the data is in-band transmission through a media independent interface; a signal generating unit, configured to generate a back pressure signal when flow control is required on the link layer side; and a back pressure signal transmission unit configured to transmit the back pressure signal to the link through the back pressure signal line Layer side, so that the link layer side controls the data sent by the back layer in response to the back pressure signal.

In another aspect, a system for data transmission of a physical layer is provided, including: a link layer device, configured to send in-band transmission data to a physical layer device by using a medium independent interface; and a physical layer device, configured to receive a link layer device to send Data, and generate a back pressure signal when the link layer device needs to be flow controlled, and transmit the back pressure signal to the link layer device through the back pressure signal line, so that the link layer device responds to the back pressure signal pair to send The data of the physical layer device is flow-controlled.

According to the technical solution of the embodiment of the present invention, the embodiment of the present invention uses the back-pressure signal line to perform the out-of-band backpressure signal transmission of the physical layer device to the link layer device, and the physical layer side needs to be on the link layer side. When the data transmission is controlled, a back pressure signal is generated, and the back pressure signal is immediately transmitted to the link layer side through the back pressure signal line, and the link layer side responds to the back pressure signal and performs data flow control, thereby reducing the flow control response lag. , to ensure the real-time flow control. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art description will be briefly described below, and the drawings in the following description are merely the present invention. Some of the embodiments can be obtained by those skilled in the art from the drawings without any inventive labor.

1 is a reference model diagram of data transmission and flow control signal transmission on a physical layer side and a link layer side in the prior art;

2 is a schematic diagram of a physical layer data transmission system according to an embodiment of the present invention; FIG. 3 is a flowchart of a physical layer data transmission method according to an embodiment of the present invention; A schematic diagram of the structure of a physical layer data transmission device. detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. The illustrated embodiments are only a part of the embodiments of the present invention, but not all embodiments. All of those obtained by those of ordinary skill in the art based on the embodiments of the present invention The embodiments thereof are all within the scope of protection of the present invention.

Referring to FIG. 2, FIG. 2 is a schematic structural diagram of a system for data transmission of a physical layer according to an embodiment of the present invention, including: a physical layer device 210 and a link layer device 220. On the one hand, the physical layer device 210 and the link layer device 220 can perform in-band transmission of data through a Media Independent Interface (ΜΠ). For example, the link layer device 220 can send in-band transmitted data to the physical layer device through the medium independent interface.

On the other hand, the physical layer device 210 is further connected to the link layer device 220 through a back pressure signal line, and the physical layer device 210 can use the back pressure signal line to stream to the link layer device 220. Out-of-band transmission of control signals. Specifically, when the physical layer device 210 needs to flow control the link layer device 220, it may generate a corresponding back pressure signal, and the back pressure signal may serve as the flow control signal and pass the The back pressure signal line is passed to the link layer device 220 to cause the link layer device to respond to the back pressure signal and transmit the data to the physical layer device 210 according to the back pressure signal.

In the embodiment of the present invention, the medium independent interface used includes but is not limited to general MIII, GMII (Gigabit Media Independent Interface), SGMII (Serial Gigabit Media Independent Interface), RGMII (Simplified Gigabit Media Independent Interface), etc. ΜΠ series interface.

Further, the in-band transmission of data may be performed between the physical layer device 210 and the link layer device 220 by using a data slice format. For example, before the link layer device 220 sends data to the physical layer device 210, it may encapsulate the data to be sent into a protocol-independent data packet, and the data is according to the size of the physical layer device 210 cached. The packet is divided into a plurality of slices, and header information is separately added to the fragment data, and the header information and the fragment data are encapsulated into data slices.

The data packet unrelated to the protocol may be a data packet in a too network packet format or other cell format. And, the header information added in each of the slice data may include: a start flag and an end flag for indicating a valid position of the slice, a logical address for identifying a corresponding position of the slice, and the like.

Correspondingly, the link layer device 220 receives the number of data transmission using the data slice format Afterwards, the data slice may be decapsulated to decompose the frame header information and the fragment data, and the fragment data is spliced according to the frame header information to obtain a complete data packet, and the The packet is decapsulated to recover the original data.

Similarly, before the physical layer device 210 sends the corresponding data to the link layer device 220, the data to be sent to the link layer device 220 may also be encapsulated into a protocol-independent data packet, and the The data packet is divided into a plurality of fragments, and header information is separately added to the fragment data, and the header information and the fragment data are encapsulated into pieces of data.

Further, in the data transmission, when the physical layer device 210 needs to perform flow control on the link layer device 220, the following two backpressure signals may be used to implement data flow control.

A back pressure signal is implemented by: the back pressure signal generated by the physical layer device 210 includes a back pressure channel ID and a back pressure signal indicating bit; wherein the back pressure channel ID is used to identify a data channel that needs flow control, and each The data channels correspond to different data packets or different data slices that need to be flow-controlled; the back pressure signal indication bit can be set to 0 or 1 to indicate that a back pressure or a back pressure is generated. For example, 0 or 1 of the indication bit may be defined as: when the indication bit is 0, it indicates that the link layer device 220 needs to be flow-controlled; when the indication bit is 1, it indicates that the link layer device needs to be revoked. 220 flow control. It should be understood that 0 or 1 set to the indication bit may also be de-defined. For example, when the indication bit is 1, it indicates that the link layer device 220 needs to be flow-controlled; when the indication bit is 0, it indicates that the pair needs to be revoked. Flow control of the link layer device 220.

Another implementation of the backpressure signal is that the backpressure signal generated by the physical layer device 210 includes clamped serial data, and the clamped serial data is mapped to N data channels by bit mapping (BIT MAP). And each of the N-bit serial data can be set to 0 or 1 respectively to indicate that a back pressure is generated or a back pressure is cancelled. For example, 0 is used to indicate that back pressure is generated, and 1 is used to indicate that back pressure is removed. In this way, the N-bit serial data can represent backpressure information of N data channels, each data channel can receive the serial data of the N-bit length, and each of the corresponding bits is set according to the setting of 0 or 1 of the corresponding bit. The data channels generate back pressure or · 敎敎 back pressure.

In addition, in a specific embodiment, in order to ensure that data transmitted by the link layer device 220 is not lost, The data buffer of the physical layer device 210 is capable of storing at least a data packet transmitted by the link layer device 220 before responding to the back pressure signal.

In the system for transmitting physical layer data according to the embodiment of the present invention, the physical layer device 210 and the link layer device 220 transmit data through a series interface, and the data is encapsulated into a protocol-independent data packet and further divided into The data slice format is transmitted. Moreover, the physical layer device 210 generates a back pressure signal when the data transmission of the link layer device 220 needs to be controlled, and transmits the back pressure signal to the link layer device 220 through the back pressure signal line. The link layer device responds to the back pressure signal after receiving the back pressure signal, such as sending a response signal to the receiving end, and performing data transmission according to the back pressure signal. The system uses the out-of-band back pressure to transmit the flow control signal (ie, the back pressure signal), which can effectively reduce the flow control response lag and ensure the real-time behavior of the flow control.

Moreover, the embodiment of the present invention indicates that the data channel that needs to be flow-controlled generates backpressure or undo backpressure by setting 0 or 1, and since each data channel corresponds to different data packets or different data slices that need to be flow-controlled, On the one hand, accurate flow control can be performed on different data packets or different data pieces that need to be flow-controlled; on the other hand, after receiving the back pressure signal, it is not required to be parsed, thereby further ensuring real-time flow control. Sex. In addition, in the embodiment of the present invention, when the physical layer device 210 and the link layer device 220 perform data transmission, the transmitting end may fragment the data packet according to the buffer size of the receiving end, and transmit the data packet in a data slice format. , which makes the packet of each transmission smaller. Therefore, the capacity requirement for the data buffer at the receiving end becomes smaller. The embodiment of the invention can reduce the buffering of device data and reduce the cost of the chip.

Referring to FIG. 3, an embodiment of the present invention provides a method for data transmission of a physical layer, including: Step 301: Performing in-band transmission of data by using a media independent interface;

Step 302: Perform an out-of-band transmission of the flow control signal by using a back pressure signal line.

Specifically, in step 301, the in-band transmission of data between the physical layer side and the link layer side may adopt a medium-independent interface. For example, the physical layer side may receive in-band transmission data sent by the link layer side. In the embodiment of the present invention, the medium independent interface may include, but is not limited to, a universal MII, a GMII (Gigabit Media Independent Interface), an SGMII (Serial Gigabit Media Independent Interface), and a RGMII (Simplified Thousand Mega media independent interface) equal to the series interface.

In step 302, when the physical layer side needs to perform flow control on the link layer side, the physical layer side generates a back pressure signal and transmits the back pressure signal to the link layer by means of a back pressure signal line. Side, so that the link layer side responds to the back pressure signal and performs data transmission according to the back pressure signal.

Further, the link layer side may perform in-band transmission of data in a data slice format. For example, before the in-band transmission of data using a media independent interface, the link layer side can encapsulate the data into protocol-independent data packets, such as Ethernet packets or other data packets in a cell format. And, according to the size of the physical layer side buffer, the link layer side may further divide the data packet into a plurality of fragments, and add frame header information such as a start flag, an end flag, and a logical address in the fragment data, and package the header information. Into the data piece.

After receiving the data transmitted in the data slice format on the link layer side, the physical layer side may decapsulate the received data piece to decompose the frame header information and the fragment data, and according to the frame header information pair. The fragment data is spliced to obtain a complete data packet; further, the physical layer side may decapsulate the data packet to recover the original data.

By segmenting the data packet by the above, adding frame header information to each of the fragments and encapsulating the data in a data slice format, so that each transmitted data packet becomes smaller, thereby reducing the physical layer side. The cache, reducing the cost of the chip.

Further, in the data transmission, when the physical layer side needs to perform flow control on the link layer side, the following two back pressure signals may be used to implement data flow control.

A back pressure signal is implemented by: a back pressure signal generated by the physical layer side includes a back pressure channel ID and a back pressure signal indicating bit; wherein the back pressure channel ID is used to identify a data channel that needs flow control, and each data channel Corresponding to different data packets or different data slices that need to be flow controlled; the back pressure signal indication bit can be set to 0 or 1 to indicate that a back pressure or a back pressure is generated. For example, 0 or 1 of the indication bit may be defined as: when the indication bit is 0, it indicates that the link layer device 220 needs to be flow-controlled; when the indication bit is 1, it indicates that the flow on the link layer side needs to be revoked. control. It should be understood that 0 or 1 set to the indication bit can also be de-defined, for example, when the indication bit is 1, it indicates that the link layer needs to be side-by-side. Flow control; When the indication bit is 0, it indicates that the flow control on the link layer side needs to be revoked.

Another implementation of the back pressure signal is that the back pressure signal generated on the physical layer side includes N-bit serial data, the N-bit serial data is mapped to N data channels by bit mapping, and the N-bit string Each bit in the line data can be set to 0 or 1 respectively to indicate the generation of back pressure or undo back pressure. For example, 0 is used to indicate that back pressure is generated, and 1 is used to indicate that back pressure is removed. In this way, the N-bit serial data can represent backpressure information of N data channels, each data channel can receive the serial data of the N-bit length, and each of the corresponding bits is set according to the setting of 0 or 1 of the corresponding bit. The data channels generate back pressure or undo back pressure.

As each data channel corresponds to a different data packet or a different data slice that needs to be flow-controlled, by setting 0 or 1 to indicate that the data channel that needs to be flow-controlled generates a back pressure or cancels the back pressure, therefore, the method provided by the embodiment of the present invention is provided. Two kinds of back-pressure signal implementations can perform accurate flow control on different data packets or different data slices that need to be flow-controlled on the one hand; on the other hand, the link layer side does not need to analyze the back-pressure signal when receiving the back pressure signal. , thus ensuring the real-time nature of flow control.

Referring to FIG. 4, an embodiment of the present invention further provides an apparatus for data transmission of a physical layer, where the apparatus for transmitting data of a physical layer may be a physical layer device, including:

a data transmission unit 401, configured to receive in-band transmission data sent by a link layer side, where the data is in-band transmission through a media independent interface;

a back pressure signal generating unit 405, configured to generate a back pressure signal when flow control is required on the link layer side;

The back pressure signal transmission unit 402 is configured to transmit the back pressure signal to the link layer side through the back pressure signal line, so that the link layer side responds to the back pressure signal and performs data transmission according to the back pressure signal.

The medium independent interface may include a Mil series interface such as a general MII, a GMII (Gigabit Media Independent Interface), an SGMII (Serial Gigabit Media Independent Interface), and an RGMII (Simplified Gigabit Media Independent Interface).

The data received by the data transmission unit 401 may be transmitted in a data slice format, where each data slice carries frame header information and fragment data, and the fragment data is generated after the data packet is processed by fragmentation. of. In order to restore the fragment data to original data, the embodiment of the present invention provides The apparatus for transmitting physical layer data may further include:

The data piece splicing unit 404 is configured to decapsulate the data piece received by the data transmission unit 401 to decompose the frame header information and the fragment data, and splicing the fragment data according to the frame header information. To get a complete packet and decapsulate the packet.

The frame header information may include: a start flag, an end flag, and a logical address corresponding to the slice, for indicating a valid position of the slice.

Further, the data transmission unit 401 is further configured to transmit data to the link layer side by using a medium independent interface. The data may also be transmitted to the link layer side in a data slice format. To this end, the device for physical layer data transmission of the device may further include:

The packet fragmentation unit 403 is configured to encapsulate the data to be sent to the link layer side into a protocol-independent data packet, and divide the data packet into multiple fragments according to the link layer side buffer size, in the fragmented data. The header information is added and encapsulated into pieces of data so that the data transmission unit 401 can transmit the data in a data slice format.

Further, in an embodiment, the back pressure signal generating unit 405 provided by the embodiment of the present invention may include: a first back pressure signal module (not shown) for generating a back pressure channel ID and a back pressure signal indication A back pressure signal of the bit, wherein the back pressure channel ID is used to identify a data channel that requires flow control, and the back pressure signal indicator bit is used to indicate that a back pressure is generated or a back pressure is cancelled.

Alternatively, in other alternative embodiments, the back pressure signal generating unit 405 may include a second back pressure signal module (not shown) for generating a back pressure signal including N bits of serial data, wherein the N bits The serial data is mapped to N data channels by bit mapping, and each of the N-bit serial data is used to indicate that a back pressure or a back pressure is respectively generated.

When the back pressure signal generating unit 405 generates the back pressure signal by using the first back pressure signal module, each data channel that needs to be flow control may be identified by using different back pressure channel IDs to correspond to flow control. Different data packets or different data slices; and, the back pressure signal indicating bit can be used to indicate that the data channel requiring flow control generates back pressure or cancels back pressure. For example, 0 or 1 of the indication bit can be defined as: When the indication bit is 0, it indicates that the link layer side needs to be flow-controlled; when the indication bit is 1 At the time, it indicates that the flow control on the link layer side needs to be revoked. Of course, the 0 or 1 set to the indication bit can also be de-defined: when the indication bit is 1, it indicates that the link layer side needs to be flow-controlled; when the indication bit is 0, it indicates that the flow on the link layer side needs to be revoked. control.

When the back pressure signal generating unit 405 generates the back pressure signal by using the second back pressure signal module, each bit (bit) of the N-bit serial data can be set to 0 or 1, respectively, where 0 It is used to indicate that a back pressure is generated, 1 is used to indicate that the back pressure is cancelled; or, the 0 or 1 can also be de-defined. Thus, the N-bit serial data can represent backpressure information of N data channels. When a backpressure signal needs to be generated, each data channel simultaneously receives the N-bit length string data, and according to the corresponding bit 0. The setting of 1 or 1 produces a back pressure or a back pressure on each of the data channels.

It should be noted that those skilled in the art can understand that all or part of the processes in the foregoing embodiments can be implemented by a computer program to instruct related hardware, and the program can be stored in a computer readable storage medium. Wherein, the program, when executed, may include the flow of an embodiment of the methods as described above. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

The method, device and data transmission system for physical layer data transmission provided by the embodiments of the present invention are described in detail above. The present invention mainly uses an out-of-band back-pressure signal line to transmit the physical layer side to the link layer side. The back pressure signal improves the real-time performance of the flow control signal and reduces the buffer of the data receiving end device, thereby reducing the cost of the chip. The description of the embodiments is only for the purpose of facilitating the understanding of the method and the concept of the present invention; any person skilled in the art can easily think of changes or substitutions within the scope of the technology disclosed in the present invention, and should be covered by the scope of the present invention. within. Therefore, the scope of the invention should be determined by the scope of the claims.

Claims

Claim

A method for data transmission of a physical layer, comprising:

The physical layer side receives the in-band transmission data sent by the link layer side, where the media layer side and the link layer side use the medium independent interface to perform in-band transmission of data;

When the physical layer side needs to flow control on the link layer side, the physical layer side generates a back pressure signal and transmits the back pressure signal to the link layer side through the back pressure signal line, so that the link layer side responds to the back pressure. The signal is transmitted according to the back pressure signal.

The method according to claim 1, wherein the data received by the physical layer side is transmitted in a data slice format, and the method further includes:

The link layer side encapsulates the data into a data packet;

According to the size of the physical layer side buffer, the link layer side divides the data packet into a plurality of fragments, and adds frame header information to the fragmented data and encapsulates the data into pieces.

3. The method according to claim 2, further comprising:

The physical layer side decapsulates the data piece received by the physical layer to decompose the frame header information and the fragment data, and splices the fragment data according to the frame header information to obtain a complete data packet;

The physical layer side decapsulates the data packet.

The method according to any one of claims 1 to 3, wherein the back pressure signal includes a back pressure channel ID and a back pressure signal indicator bit, wherein the back pressure channel ID is used to identify a need A flow control data channel is provided, the back pressure signal indicating bit is used to indicate that a back pressure is generated or a back pressure is cancelled.

The method according to any one of claims 1 to 3, wherein the back pressure signal comprises N-bit serial data, and the N-bit serial data is mapped to N data channels by bit mapping And each of the N-bit serial data is used to indicate that a back pressure is generated or a back pressure is cancelled.

6. A device for data transmission of a physical layer, comprising:

a data transmission unit, configured to receive in-band transmission data sent by a link layer side, where the data is in-band transmission through a media independent interface; a back pressure signal generating unit, configured to generate a back pressure signal when flow control is required on the link layer side; and a back pressure signal transmission unit configured to transmit the back pressure signal to the link layer side through the back pressure signal line, The link layer side is caused to respond to the back pressure signal and perform data transmission according to the back pressure signal.

The device according to claim 6, wherein the data received by the data transmission unit is transmitted in a data slice format, wherein each data slice carries frame header information and fragment data, and The fragmentation data is generated by the fragmentation processing of the data packet.

8. The device according to claim 7, further comprising:

a data piece splicing unit, configured to decapsulate the data piece received by the data transmission unit to decompose the frame header information and the fragment data, and splicing the fragment data according to the frame header information to obtain Complete packet and decapsulate the packet.

The apparatus according to any one of claims 6 to 8, wherein the back pressure signal generating unit comprises:

a first back pressure signal module, configured to generate a back pressure signal including a back pressure channel ID and a back pressure signal indicating bit, wherein the back pressure channel ID is used to identify a data channel that needs flow control, and the back pressure signal indicating bit Used to indicate the generation of back pressure or undo back pressure.

a second back pressure signal module, configured to generate a back pressure signal including N-bit serial data, wherein the N-bit serial data is mapped to N data channels by bit mapping, and the N-bit serial data Each bit is used to indicate a back pressure or a back pressure.

11. A system for physical layer data transmission, comprising a physical layer device and a link layer device, wherein:

The link layer device is configured to send the data transmitted in the inband to the physical layer device by using the medium independent interface; the physical layer device is configured to receive the data sent by the link layer device, and generate the reverse when the flow control of the link layer device is required. Pressing the signal, and transmitting the back pressure signal to the link layer device through the back pressure signal line, so that the link layer device responds to the back pressure signal and performs data transmission according to the back pressure signal.

12. The system of claim 11 wherein:

The link layer device is further configured to encapsulate the data to be sent to the physical layer device into a data packet, divide the data packet into multiple fragments according to the size of the physical layer side cache, and separately add the data in the fragment data. The header information is encapsulated into data slices for data transmission in a data slice format.

13. The system of claim 12, wherein

The physical layer device is further configured to decapsulate the data piece received by the device to decompose the frame header information and the fragment data, and splicing the fragment data according to the frame header information to obtain complete data. Packet, and decapsulate the data packet.

The method according to any one of claims 11 to 13, wherein the back pressure signal includes a back pressure channel ID and a back pressure signal indicator bit, wherein the back pressure channel ID is used to identify a need A flow control data channel is provided, the back pressure signal indicating bit is used to indicate that a back pressure is generated or a back pressure is cancelled.

The method according to any one of claims 11 to 13, wherein the back pressure signal comprises N-bit serial data, and the N-bit serial data is mapped to N data channels by bit mapping And each of the N-bit serial data is used to indicate that a back pressure is generated or a back pressure is cancelled.