CN115134049A - Communication method and device - Google Patents

Abstract

The application provides a communication method and device, which can solve the problem that the message sending rate of a client is reduced and can be applied to a communication system. The communication method is applied to first equipment, the first equipment comprises a TCP layer and an intermediate layer, and the intermediate layer is a lower layer of the TCP layer. The communication method comprises the following steps: the middle layer receives a first message from the second device. Wherein the first message instructs the TCP layer to retransmit the first data. The intermediate layer sends the first data to the second device and discards the first message. Thus, when receiving the indication of retransmitting the lost message, the intermediate layer not only can retransmit the lost message, but also can filter the indication, and the TCP layer is prevented from receiving the indication. Therefore, under the condition that a channel between the client and the server is not congested and a message is lost occasionally, the TCP layer cannot reduce a congestion window and reduce the message sending rate.

Description

Communication method and device

technical field

The present application relates to the field of communication, and in particular, to a communication method and device.

Background technique

Transmission Control Protocol (TCP) is a connection-oriented, reliable, byte stream-based transport layer communication protocol. The reliability of TCP is mainly achieved by the retransmission mechanism. Specifically, when a packet sent by a client (eg, a mobile phone) to a server (eg, a server) is lost, the server may instruct the client to retransmit the lost packet.

At present, if a packet is lost, the client not only retransmits the lost packet, but also greatly reduces the congestion window, which reduces the client's sending window and reduces the packet sending rate. That is to say, packet loss will cause the client's packet sending rate to drop.

SUMMARY OF THE INVENTION

Embodiments of the present application provide a communication method and device, which can solve the problem of a decrease in the packet sending rate of the client.

To achieve the above object, the application adopts the following technical solutions:

In a first aspect, a communication method is provided. The communication method is applied to a first device, where the first device includes a TCP layer and an intermediate layer, and the intermediate layer is a lower layer of the TCP layer. The communication method includes: an intermediate layer receives a first packet from a second device. The first packet instructs the TCP layer to retransmit the first data. The middle layer sends the first data to the second device and discards the first packet.

Based on the communication method described in the first aspect, when receiving the instruction to retransmit the lost packet, the intermediate layer can not only retransmit the lost packet, but also filter the instruction to prevent the TCP layer from receiving the instruction. In this way, when the channel between the client and the server is not congested, when packets are occasionally lost, the TCP layer will not reduce the congestion window and reduce the packet sending rate.

In a possible design solution, before the middle layer receives the first packet from the second device, the communication method described in the first aspect may further include: the middle layer buffers the message from the TCP layer, and/or, the second device message. In this way, an implementation manner in which the intermediate layer reads out the lost packets from the cache (also referred to as a buffer) and retransmits the lost packets can be provided, and the efficiency of the intermediate layer retransmission of the packets can be improved.

In a possible design solution, the above-mentioned intermediate layer receiving the first packet from the second device may include: the intermediate layer determining multiple confirmation packets with the same confirmation number in all the packets from the second device. The intermediate layer determines that the nth confirmation message in the plurality of confirmation messages is the first message, and n may be an integer greater than or equal to 2. In other words, when the number of the same acknowledgment packets received from the second device reaches n, the intermediate layer acknowledges the reception of the indication of retransmission of the lost packets. In this way, it is possible to avoid retransmitting the packets that are still transmitted in the network and can be received by the server, and reduce the number of retransmissions.

Optionally, n can be 2. In this way, compared with retransmitting the lost packet after receiving more than 3 retransmission instructions, when the retransmission instruction is received for the first time, the intermediate layer can immediately find the lost packet in the cache and retransmit it, so that it can Retransmit lost packets faster and improve the efficiency of data retransmission.

In a possible design solution, the communication method described in the first aspect may further include: the middle layer receives a second packet, the second packet includes first window indication information, and the first window indication information indicates the length of the first window. . The middle layer sends a third packet, where the third packet includes second window indication information, where the second window indication information indicates the length of the second window, and the length of the second window is greater than or equal to the length of the first window. In other words, when the TCP layer sends a packet carrying window indication information to the second device, and/or when the second device sends a packet carrying window indication information to the TCP layer, the intermediate layer can amplify the window indication information. the length of the window in the message, and forward the modified message. In this way, the TCP layer and/or the second device can be made to consider that the receiving buffer of the data receiver is sufficient, so that the TCP layer and/or the second device can receive the data with a larger sending window and a higher sending rate. It can improve the transmission rate by sending data.

Optionally, the first window indication information may include a first window scaling factor field and a first window size field, and the second window indication information may include a second window scaling factor field and a second window size field. The length of the second window is greater than or equal to the length of the first window, and may include one or more of the following: the value of the second window scaling factor field is greater than or equal to the value of the first window scaling factor field, or, the second window size field The value of is greater than or equal to the value of the first window size field.

Optionally, the above-mentioned second window may be a receiving window of the second device. The foregoing intermediate layer receiving the second packet may include: the intermediate layer receiving the second packet from the second device. The middle layer sending the third packet may include: the middle layer sending the third packet to the TCP layer, and the second window indication information is used to determine the sending window of the first device. In other words, the middle layer can intercept the second packet sent by the second device to the TCP layer, modify the first window in the second packet to the second window, and use the modified second packet as the third The message is sent to the TCP layer. Since the length of the second window in the third packet is greater than or equal to the length of the first window, the TCP layer will consider that the receiving buffer of the second device is sufficient, so that a larger sending window and a higher sending rate are used to send the second device to the second device. The device sends data, which in turn can increase the transfer rate. The first window in the second packet can be understood as an unmodified receiving window of the second device, and the second window in the third packet can be understood as a modified receiving window by the second device.

Further, the communication method described in the first aspect may further include: the middle layer sends a data packet to the second device according to the length of the first window indicated by the first window indication information. For example, when receiving data packets from the TCP layer, the intermediate layer can store these data packets in the cache, and the intermediate layer can also send the data packets to the second device according to the length of the first window indicated by the first window indication information. Send data packets. Since the length of the first window is the unmodified receiving window of the second device, it is possible to avoid an overload error of the receiving window of the second device caused by too much data.

Optionally, the above-mentioned second window may be a receiving window of the first device. The foregoing intermediate layer receiving the second packet may include: the intermediate layer receiving the second packet from the TCP layer. Sending the third packet by the middle layer may include: the middle layer sending the third packet to the second device, and the second window indication information is used to determine the sending window of the second device. In other words, the middle layer can intercept the second packet sent by the TCP layer to the second device, modify the first window in the second packet to the second window, and use the modified second packet as the third The message is sent to the second device. Since the length of the second window in the third packet is greater than or equal to the length of the first window, the second device considers that the receiving buffer of the TCP layer is sufficient, and sends the data to the TCP layer with a larger sending window and a higher sending rate. Data is sent, which in turn can increase the transmission rate. The first window in the second packet can be understood as the unmodified receiving window of the TCP layer, and the second window in the third packet can be understood as the receiving window after the TCP layer has been modified.

Further, the communication method described in the first aspect may further include: the middle layer sends the data packet to the TCP layer according to the length of the first window indicated by the first window indication information. For example, when receiving data packets from the second device, the intermediate layer may store these data packets in the cache, and the intermediate layer may also send the data packets to the TCP layer according to the length of the first window indicated by the first window indication information. Send data packets. Since the length of the first window is the unmodified receiving window of the TCP layer, it is possible to avoid an overload error of the receiving window of the TCP layer caused by too much data.

Optionally, the above-mentioned second window indication information may be determined by the service corresponding to the second packet. For example, after receiving the second packet, the intermediate layer determines the quintuple information in the second packet. The quintuple information corresponds to the length of the service and the window, respectively. The middle layer determines the third packet according to the length of the window corresponding to the quintuple information. In this way, the middle layer can modify the window indication information in the message according to the service, thereby modifying the length of the uplink window or downlink window corresponding to the service. The uplink window or downlink window corresponding to the small-volume service is reduced. In this way, the data transmission rate and transmission delay of different services can be made more reasonable.

In a possible design solution, the communication method described in the first aspect may further include: the middle layer receives the fourth packet from the second device. The fourth message may be an acknowledgement message. The intermediate layer determines whether there is a fifth packet in all the confirmation packets received by the intermediate layer. The confirmation number of the fifth message is the same as the confirmation number of the fourth message. If the fifth packet does not exist in all the confirmation packets received by the intermediate layer, the intermediate layer sends the fourth packet to the TCP layer. In this way, the TCP layer can send the next data packet to the second device according to the acknowledgment number in the acknowledgment packet.

In a possible design solution, the middle layer is located between the TCP layer and the internet protocol (internet protocol, IP) layer. 7, when the middle layer is located between the TCP layer and the IP layer in the network layer, the message received by the middle layer is a TCP message, and the middle layer can analyze the TCP message; when the middle layer is the lower layer of the IP layer When the packet is received by the intermediate layer, the packet is an IP packet. The intermediate layer needs to parse the header of the IP packet, extract the TCP packet from the IP packet, and then analyze the TCP packet. In other words, the intermediate layer is located between the TCP layer and the IP layer, which can reduce the overhead of parsing packets by the intermediate layer, thereby improving processing efficiency.

In a possible design solution, the communication method described in the first aspect may further include: within the first time period, the number of first packets received with different acknowledgment numbers exceeds the congestion threshold, and/or the packet loss rate reaches When the packet loss threshold is reached, the middle layer sends the first message to the TCP layer. The first message is used to instruct the TCP layer to reduce the sending rate. In this way, when the channel between the client and the server is congested, the middle layer can feed back the indication of retransmission of lost packets to the TCP layer, so that the TCP layer can reduce the congestion window, reduce the packet sending rate, and avoid the communication between the client and the server. further congestion of the inter-channel channel and improve the channel quality.

In a possible design solution, the first packet carries a selection acknowledgment SACK option, and the SACK option is used to indicate retransmission of the first data. Among them, the SACK option can indicate which data packets are not received and which data packets are received. For example, assuming that the SACK option is used to indicate that data packets with sequence numbers 100, 300, and 400 have not been received, and data packets with sequence numbers 200 and 500 have been received, then the intermediate layer receives the first packet carrying the SACK option. It can be determined that the data packets with serial numbers 100, 300, and 400 may be lost, so that these multiple data packets can be retransmitted at one time instead of one by one to avoid connection timeout due to long waiting time on the server side. , to improve the retransmission efficiency of the client.

In a second aspect, a communication device is provided. The communication device includes: a processing module and a transceiver module. The processing module includes a transmission control protocol TCP layer and an intermediate layer of the communication device, and the intermediate layer is the lower layer of the TCP layer. Wherein, the middle layer of the communication device is configured to use the transceiver module to receive the first packet from the second device, where the first packet instructs the TCP layer to retransmit the first data. The middle layer of the communication device is further configured to discard the first packet, and use the transceiver module to send the first data to the second device.

In a possible design solution, the middle layer of the communication device is further configured to buffer the packets from the TCP layer and/or the second device.

In a possible design solution, the middle layer of the communication device is further configured to determine a plurality of acknowledgment packets with the same acknowledgment number in all packets from the second device. The middle layer of the communication device is further configured to determine that the nth confirmation message in the plurality of confirmation messages is the first message, and n may be an integer greater than or equal to 2.

Optionally, n can be 2.

In a possible design solution, the middle layer of the communication device is further configured to receive the second message by using the transceiver module. The second packet may include first window indication information, where the first window indication information indicates the length of the first window. The middle layer of the communication device is also used for sending the third message by using the transceiver module. The third packet may include second window indication information, where the second window indication information indicates the length of the second window, and the length of the second window is greater than or equal to the length of the first window.

Optionally, the first window indication information may include a first window scaling factor field and a first window size field, and the second window indication information may include a second window scaling factor field and a second window size field. The length of the second window is greater than or equal to the length of the first window, and may include one or more of the following: the value of the second window scaling factor field is greater than or equal to the value of the first window scaling factor field, or, the second window size field The value of is greater than or equal to the value of the first window size field.

Optionally, the above-mentioned second window may be a receiving window of the second device. The middle layer of the communication device is further configured to receive the second message from the second device by using the transceiver module. The middle layer of the communication device is further configured to send a third message to the TCP layer by using the transceiver module, and the second window indication information is used to determine the sending window of the communication device.

Further, the middle layer of the communication device is further configured to use the transceiver module to send a data packet to the second device according to the length of the first window indicated by the first window indication information.

Optionally, the above-mentioned second window may be a receiving window of the communication device. The middle layer of the communication device is further configured to receive the second message from the TCP layer by using the transceiver module. The middle layer of the communication device is further configured to use the transceiver module to send a third message to the second device, and the second window indication information is used to determine the sending window of the second device.

Further, the middle layer of the communication device is further configured to send the data packet to the TCP layer by using the transceiver module and according to the indicated length of the first window.

Optionally, the above-mentioned second window indication information may be determined by the service corresponding to the second packet.

In a possible design solution, the middle layer of the communication device is further configured to receive the fourth message from the second device by using the transceiver module. The fourth message is an acknowledgement message. The middle layer of the communication device is further configured to judge whether there is a fifth message in all the confirmation messages received by the middle layer. The confirmation number of the fifth message is the same as the confirmation number of the fourth message. The middle layer of the communication device is further configured to use the transceiver module to send the fourth message to the TCP layer if the fifth message does not exist in all the confirmation messages received by the middle layer.

In a possible design solution, the middle layer is located between the TCP layer and the IP layer.

In a possible design solution, the middle layer of the communication device is further configured to receive, within the first time period, the number of first packets with different acknowledgment numbers exceeding the congestion threshold, and/or the packet loss rate reaching the packet loss threshold When the sending and receiving module is used, the first message is sent to the TCP layer. The first message is used to instruct the TCP layer to reduce the sending rate.

In a possible design solution, the first packet carries a selection acknowledgment SACK option, and the SACK option is used to indicate retransmission of the first data.

Optionally, the transceiver module may include a receiving module and a sending module. Wherein, the sending module is used for realizing the sending function of the communication device, and the receiving module is used for realizing the receiving function of the communication device.

Optionally, the communication device according to the second aspect may further include a storage module, where the storage module stores programs or instructions. When the processing module executes the program or the instruction, the communication device can execute the communication method described in the first aspect.

It should be noted that the communication device described in the second aspect may be a first device (such as a mobile phone, a server, etc.), a chip (system) or other components or components that can be provided in the first device, or a The device of the first device is not limited in this application.

In addition, for the technical effect of the communication apparatus described in the second aspect, reference may be made to the technical effect of the communication method described in the first aspect, which will not be repeated here.

In a third aspect, a communication device is provided. The communication device includes: a processor, which is coupled with a memory, and the memory is used for storing a computer program; the processor is used for executing the computer program stored in the memory, so that the communication device executes the possible implementations described in the first aspect communication method.

In a possible design, the communication device described in the third aspect may further include a transceiver. The transceiver may be a transceiver circuit or an input/output interface. The transceiver may be used for the communication device to communicate with other communication devices.

In this application, the communication apparatus described in the third aspect may be a first device (such as a mobile phone, a server, etc.), or a chip or a chip system provided inside the first device.

For the technical effect of the communication apparatus described in the third aspect, reference may be made to the technical effect of the communication method described in the implementation manner of the first aspect, which will not be repeated here.

In a fourth aspect, a processor is provided. Wherein, the processor is configured to execute the communication method described in the possible implementation manner of the first aspect.

In a fifth aspect, a communication system is provided. The communication system includes a first device and a second device. The first device includes a TCP layer and an intermediate layer, and the intermediate layer is a lower layer of the TCP layer.

In a sixth aspect, a computer-readable storage medium is provided. The computer-readable storage medium includes a computer program or instruction; when the computer program or instruction is executed on a computer, the computer is made to execute the communication method described in the possible implementation manner of the first aspect.

In a seventh aspect, a computer program product is provided, the computer program product includes a computer program or an instruction, when the computer program or instruction is run on a computer, the computer is made to execute the communication method described in the possible implementation manner of the first aspect .

Description of drawings

1 is a schematic diagram of the architecture of TCP/IP provided by an embodiment of the present application;

2 is a schematic diagram of a connection establishment process and a data transmission process of TCP provided by an embodiment of the present application;

3 is a schematic diagram of a congestion window provided by an embodiment of the present application;

FIG. 4 is a schematic diagram 1 of the architecture of a communication system provided by an embodiment of the present application;

FIG. 5 is a second schematic diagram of the architecture of a communication system according to an embodiment of the present application;

FIG. 6 is a schematic structural diagram 1 of an electronic device according to an embodiment of the present application;

7 is a schematic diagram of the architecture of a communication protocol in an electronic device provided by an embodiment of the present application;

FIG. 8 is a schematic flowchart 1 of a communication method provided by an embodiment of the present application;

FIG. 9 is a second schematic flowchart of a communication method provided by an embodiment of the present application;

FIG. 10 is a schematic diagram of an application scenario of the communication method provided by the embodiment of the present application;

FIG. 11 is a schematic structural diagram 1 of a communication device provided by an embodiment of the present application;

FIG. 12 is a second schematic structural diagram of a communication apparatus provided by an embodiment of the present application.

Detailed ways

First, for ease of understanding, related terms and concepts that may be involved in the embodiments of the present application are introduced below.

1. TCP

TCP is a protocol in transmission control protocol/internet protocol (TCP/IP). Specifically, taking the four-layer reference model of TCP/IP as an example, as shown in FIG. 1 , the four-layer reference model of TCP/IP includes, from top to bottom, an application layer, a transport layer, a network layer and a network interface layer. Among them, TCP is a protocol in the transport layer, which may also be called the TCP layer.

2. TCP packets

TCP packets can be generated by the TCP layer. For example, when the mobile phone sends data to the server, various applications in the mobile phone (such as WeChat, Douyin, etc.) can generate data to be sent, and send the data to be sent to the application layer, which will process the data to be sent by the application layer. , and then sent to the TCP layer. Then, the TCP layer can further encapsulate the data to be sent, thereby generating a TCP packet.

Correspondingly, when the mobile phone receives a TCP packet from other devices (such as a server), the TCP layer in the mobile phone can also parse the TCP packet, obtain the data carried in the TCP packet, and parse the parsed data. It is sent to the corresponding application through the application layer.

A TCP packet includes a TCP header (TCP header) and data. Among them, some fields included in the TCP header are as follows: sequence number (Seq), acknowledgment number (Ack), acknowledgment number control bit (ACK), synchronization sequence number control bit (SYN), window size (winsize), options and padding. Among the options are the window shrink option (WSOPT).

The sequence number is used to indicate: the sequence number of the first byte of data carried by the TCP packet. For example, a TCP packet carries 200 bytes of data. Assuming that the sequence numbers of the 200 bytes of data are 200-399 (each byte corresponds to a sequence number), the sequence number of the TCP packet is 200, and so on. The sequence number of the next TCP packet is 400.

The acknowledgment number is used to indicate: the expected sequence number of the next received TCP packet. For example, the server (server) has received data with serial numbers 200-399, and expects the next TCP packet sent by the client to have a serial number of 400. When the server feeds back TCP packets to the client, it can set the TCP packet. The confirmation number in the text is 400.

The acknowledgment number control bit is used to indicate whether the acknowledgment number in the TCP message is valid. For example, when the confirmation number control bit is 1, it means the confirmation number is valid, and when it is 0, it means that the confirmation number is invalid. Among them, the TCP message whose acknowledgment number control bit is 1 can be called an ACK message or an acknowledgment message. The acknowledgment message indicates that the server has received the last TCP message sent by the client, and indicates the next TCP message sent by the client. The sequence number of the data carried in the TCP packet.

The synchronization sequence number control bit is used in the connection establishment process of TCP (also known as the TCP three-way handshake). The first two handshakes in the TCP three-way handshake.

The window size and window scaling factor are used to indicate the size of the server's receive buffer, so as to control the rate at which the client sends data, so as to achieve the purpose of flow control. Among them, assuming that the window size is N and the window scaling factor is s, the size of the receiving buffer of the server = N*2^s. For example, if the TCP message sent by the mobile phone to the server, the window size = 2048, and the window scaling factor = 3, the size of the mobile phone's receiving buffer = 2048*2^3 = 16384 bytes, and then the server sends data to the mobile phone. , the rate of sending data to the mobile phone needs to be determined according to the size of the receiving buffer of the mobile phone.

It should be noted that, for the fields not introduced in the above-mentioned TCP header, reference may be made to the provisions of the prior art, and details are not described herein again.

3. TCP connection establishment process and data transmission process

Please refer to Fig. 2, the connection establishment process of TCP may include the following steps 1-step 3:

Step 1, the client sends a first handshake message to the server, and the server receives the first handshake message from the client.

Among them, the synchronization sequence number control bit in the first handshake message=1, the sequence number=ISN(c), the c in the ISN(c) refers to the client, and the ISN(c) can be randomly generated, and can also be called the initial Serial number (initial sequence number, ISN). In addition, the first handshake message may also carry a window size and a window scaling factor to determine the size of the receiving buffer of the client.

Step 2, the server sends a second handshake message to the client, and the client receives the second handshake message from the server.

Among them, the synchronization sequence number control bit in the second handshake message=1, the confirmation number control bit=1, and the confirmation number=ISN(c)+1, indicating that the first handshake message has been received, and the sequence number=ISN(s) , the s in the ISN(s) refers to the server, and the ISN(s) can also be randomly generated. In addition, the second handshake message may also carry the window size and the window scaling factor to indicate the size of the receiving buffer of the server.

Step 3, the client sends a third handshake message to the server, and the server receives the third handshake message from the client.

Wherein, the confirmation number control bit in the third handshake message=1, and the confirmation number=ISN(s)+1, indicating that the second handshake message has been received, and the sequence number=ISN(c)+1.

After completing the above-mentioned TCP three-way handshake, both the client and the server are in a connection establishment (ESTABLISHED) state, and data transmission can be performed. Among them, the TCP protocol is duplex, that is to say, the client can send data to the server, and the server can also send data to the client. A party may be referred to as the data recipient. In addition, for the client, when the client receives a data packet from the server, the TCP packet received by the client can be called a downlink packet; when the client sends a data packet to the server, the client sends TCP packets can be called upstream packets.

Continuing to take the example of sending a data message from the client to the server, please refer to FIG. 2 again. The data transmission process may include the following steps 4 and 5:

Step 4, the client sends a data packet to the server, and the server receives the data packet from the client.

Step 5, the server sends a confirmation message to the client, and the client receives the confirmation message from the server.

Exemplarily, assuming that the data packet sent by the client to the server carries 100 bytes of data, and the sequence number in the data packet is 100, then when the server receives the data packet, it can send the data to the client. The confirmation message, and the confirmation number control bit in the confirmation message=1, and the confirmation number=200. The confirmation message is used to indicate that the client has received the data message, so as to indicate that the sequence number of the first data in the next data sent by the client is 200. In other words, during the data transmission process, every time the server receives a TCP packet from the client, it needs to feed back an acknowledgement packet to the client to inform the client that the data has been received and the data to be transmitted next.

4. TCP retransmission mechanism

In the above steps 4 and 5, the data message or the confirmation message may be lost, so that the server cannot receive the complete data normally. Therefore, in order to realize the reliability of transmission, there are retransmission mechanisms in TCP, such as timeout retransmission mechanism and fast retransmission mechanism.

Taking the fast retransmission mechanism as an example, when a data packet is lost, the server will repeatedly feed back an acknowledgment packet with the same acknowledgment number to the client to indicate retransmission of the lost data. When the received acknowledgment packets carrying the same acknowledgment number reach the retransmission threshold (for example, 3), the client will retransmit the data indicated by the acknowledgment packet to the server. The confirmation message carrying the same confirmation number may also be referred to as a retransmission message.

Among them, within the same period of time, the client can continuously send multiple data packets to the server, and the server will feed back a corresponding confirmation packet every time it receives a data packet. However, if a packet loss occurs in these consecutive multiple data packets, the client will repeatedly feed back an acknowledgment packet to instruct to retransmit the lost packet. For example, suppose the client sends 4 data packets to the server, each data packet carries 100 bytes of data, and the serial numbers are 100, 200, 300, and 400 respectively. If the data packet with sequence number 200 is lost, the server will repeatedly feed back the confirmation packet with sequence number 200.

In addition, in the above fast retransmission mechanism, the server may send an acknowledgement packet carrying a SACK (selective acknowledgment, selective acknowledgment) option to the client to indicate which data packets have not been received and which data packets have been received. For example, suppose the client sends 10 data packets to the server, each data packet carries 100 bytes of data, the sequence numbers are 100, 200, ..., 1000, and only the sequence number 200 is among the 10 data packets. , 500, 600 data packets are lost, and other data packets are correctly received by the server, then when the server sends back an acknowledgment packet, it will also carry the SACK option in the feedback acknowledgment packet. The SACK option is used to indicate that data packets with sequence numbers 200, 500, and 600 have not been received, and data packets with sequence numbers of 100, 300, 400, 700, 800, 900, and 1000 have been received. In this way, when the client receives the acknowledgment packet carrying the SACK option, it can determine that the data packets with sequence numbers of 200, 500, and 600 may be lost, so that the multiple data packets can be retransmitted at one time instead of one by one. To avoid the connection timeout (timeout) on the server side due to long waiting time, and improve the retransmission efficiency of the client side.

In this embodiment of the present application, the packet loss includes situations such as packet loss or error in a wired link or a wireless link, which is not limited in this embodiment of the present application.

5. Sliding windows and congestion windows

In the TCP protocol, the sliding window includes a sending window and a receiving window, the sending window is maintained by the data sender, and the receiving window is maintained by the data receiver. The sending window refers to the data that can be sent in the data to be sent, and the receiving window refers to the data that can be received in the data to be received. The length of the receive window corresponds to the size of the receive buffer of the data receiver. For example, the size of the receive buffer of the data receiver may be greater than or equal to the length of the receive window of the data receiver. The data sender also maintains a congestion window, the length of the sending window = min (the length of the receiving window, the length of the congestion window), for example, the length of the receiving window of the data receiver is 70 bytes, and the length of the congestion window is 50 bytes. , then the length of the sending window of the data sender=min (70 bytes, 50 bytes)=50 bytes. In addition, in the upstream direction (that is, the client sends data to the server), the sending window maintained by the client may also be called an upstream sending window, and the receiving window maintained by the server may also be called an upstream receiving window. In the downstream direction (that is, the client receives data from the server), the receiving window maintained by the client may also be referred to as a downstream receiving window, and the sending window maintained by the server may also be referred to as a downstream sending window.

At present, as shown in FIG. 3 , after the client establishes a connection with the server, in the process of data interaction, with the change of time, the length of the congestion window of the client will gradually increase to the peak value of the congestion window. However, in this process, when a packet is lost, the TCP layer of the client will retransmit the lost packet and greatly reduce the length of the congestion window (for example, adjust the congestion window to the minimum value), resulting in a reduction of the client's sending window. This in turn reduces the client's sending rate. Also, it may not be necessary for the client's TCP layer to adjust the congestion window to a minimum value as long as lost packets are retransmitted. For example, when the channel between the client and the server is good, the lost packets are usually caused by accidental factors such as noise, and the channel status has not deteriorated. ), the client does not need to reduce the congestion window. For another example, when the channel between the client and the server fluctuates but is not congested, when packets are lost, the client does not need to adjust the congestion window to the minimum value.

The technical solutions in the present application will be described below with reference to the accompanying drawings.

A communication method provided in this embodiment of the present application can be applied to various communication systems, for example, a wired communication system or a wireless communication system. Wherein, the wireless communication system may include: a wireless fidelity (wireless fidelity, WiFi) system, a vehicle-to-everything (V2X) communication system, a device-todevie (D2D) communication system, a vehicle networking communication system, 4th generation (4G) mobile communication systems, such as longterm evolution (LTE) systems, worldwide interoperability for microwave access (WiMAX) communication systems, 5th generation (5G) mobile communication systems Communication systems, such as a new radio (new radio, NR) system, and future communication systems, such as a sixth generation (6th generation, 6G) mobile communication system, etc.

Please refer to FIG. 4 , which is a first schematic diagram of the architecture of a communication system according to an embodiment of the present application. The communication system to which the communication method provided in the embodiment of the present application is applied may include: a first device and a second device, where the first device includes a TCP layer and an intermediate layer, and the intermediate layer is a lower layer of the TCP layer. Wherein, when the first device and the second device interact based on the TCP protocol, the first device may be the client and the second device may be the server, or the first device may be the server and the second device may be the client. This application The embodiment does not limit this.

The first device and the second device may specifically be: a mobile phone, a server, a TV (also called a smart screen, a large-screen device, etc.), a tablet computer (Pad), a personal computer (PC), a notebook computer, Desktop computers, in-vehicle devices, wearable devices (such as Bluetooth headsets, smart watches, etc.), audio, virtual reality (VR) terminal devices, augmented reality (AR) terminal devices, ultra-mobile personal computers (ultra- mobile personal computer (UMPC), netbook, personal digital assistant (PDA), wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical Terminal, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, artificial intelligence (artificial intelligence) equipment etc., the embodiments of the present application do not impose any limitations on this.

Exemplarily, please refer to FIG. 5 , for example, the communication system includes a mobile phone, a TV, a notebook computer and a server. The first device and the second device may be any one of a mobile phone, a TV, a notebook computer and a server.

In this embodiment of the present application, a wired or wireless connection may be used between the first device and the second device to implement data interaction. For example, the communication network shown in FIG. 5 includes a network device 1 (eg, a base station) and a network device 2 (eg, a router). If the first device is a mobile phone and the second device is a server, the mobile phone can access the network The network device 1 and the server can access the network device 2 of the network to interact with each other. For another example, if the first device is a mobile phone and the second device is a notebook computer, the mobile phone and the notebook computer may be located in the same WiFi network, and interact through the WiFi network. For another example, a mobile phone and a laptop computer can log in to the same account (for example, a Huawei account) and interact through a server corresponding to the account. The server may be the server shown in FIG. 5 above, or may be other servers.

In the embodiment of the present application, referring to FIG. 5 , the first device is a mobile phone and the second device is a server as an example. The mobile phone is provided with a TCP layer and an intermediate layer, and the intermediate layer is the lower layer of the TCP layer. The middle layer can receive TCP packets from the server, and then send the TCP packets to the TCP layer. Wherein, when the middle layer receives the first packet from the server, and the first packet is used to instruct the TCP layer to retransmit the first data, it sends the first data to the server and discards it (it may also be filtering or deleting) the first message. In this way, the middle layer can not only complete the retransmission of lost data, but also filter the retransmitted packets sent to the TCP layer, thereby preventing the TCP layer of the mobile phone from reducing the packet sending rate due to receiving the retransmitted packets.

The communication system provided by the embodiments of the present application has been described above with reference to FIG. 4 and FIG. 5 , and the implementation of the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

Illustratively, still taking a mobile phone as the first device in the above communication system as an example, please refer to FIG. 6 , which shows a schematic structural diagram of a mobile phone 600 .

The mobile phone 600 may include a processor 610, an external memory interface 620, an internal memory 621, a universal serial bus (USB) interface 630, an antenna 1, an antenna 2, a mobile communication module 650, a wireless communication module 660, and an audio module 670 , speaker 670A, receiver 670B, microphone 670C, headphone jack 670D, sensor module 680, etc.

It can be understood that the structures illustrated in the embodiments of the present invention do not constitute a specific limitation on the mobile phone 600 . In other embodiments of the present application, the mobile phone 600 may include more or less components than shown, or some components are combined, or some components are separated, or different components are arranged. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

The processor 610 may include one or more processing units, for example, the processor 610 may include an application processor (application processor, AP), a modem processor, a graphics processor (graphics processing unit, GPU), an image signal processor ( image signal processor, ISP), controller, memory, video codec, digital signal processor (DSP), baseband processor, and/or neural-network processing unit (NPU), etc. . Wherein, different processing units may be independent devices, or may be integrated in one or more processors.

A memory may also be provided in the processor 610 for storing instructions and data. In some embodiments, the memory in processor 610 is cache memory. This memory may hold instructions or data that have just been used or recycled by the processor 610 . If the processor 610 needs to use the instruction or data again, it can be called directly from the memory. Repeated accesses are avoided and the waiting time of the processor 610 is reduced, thereby increasing the efficiency of the system.

The wireless communication function of the mobile phone 600 can be implemented by the antenna 1, the antenna 2, the mobile communication module 650, the wireless communication module 660, the modulation and demodulation processor, the baseband processor, and the like.

Antenna 1 and Antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in handset 600 may be used to cover a single or multiple communication frequency bands. Different antennas can also be reused to improve antenna utilization. For example, the antenna 1 can be multiplexed as a diversity antenna of the wireless local area network. In other embodiments, the antenna may be used in conjunction with a tuning switch.

The mobile communication module 650 can provide wireless communication solutions including 2G/3G/4G/5G etc. applied on the mobile phone 600 . The mobile communication module 650 may include at least one filter, switch, power amplifier, low noise amplifier (LNA) and the like. The mobile communication module 650 can receive electromagnetic waves from the antenna 1, filter, amplify, etc. the received electromagnetic waves, and transmit them to the modulation and demodulation processor for demodulation. The mobile communication module 650 can also amplify the signal modulated by the modulation and demodulation processor, and then convert it into electromagnetic waves for radiation through the antenna 1 . In some embodiments, at least part of the functional modules of the mobile communication module 650 may be provided in the processor 610 . In some embodiments, at least part of the functional modules of the mobile communication module 650 may be provided in the same device as at least part of the modules of the processor 610 .

The wireless communication module 660 can provide applications on the mobile phone 600 including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), bluetooth (BT), global navigation satellite systems ( global navigation satellite system, GNSS), frequency modulation (frequency modulation, FM), near field communication technology (near field communication, NFC), infrared technology (infrared, IR) and other wireless communication solutions. The wireless communication module 660 may be one or more devices integrating at least one communication processing module. The wireless communication module 660 receives electromagnetic waves via the antenna 2 , frequency modulates and filters the electromagnetic wave signals, and sends the processed signals to the processor 610 . The wireless communication module 660 can also receive the signal to be sent from the processor 610 , perform frequency modulation on the signal, amplify the signal, and then convert it into an electromagnetic wave for radiation through the antenna 2 .

In some embodiments, the antenna 1 of the mobile phone 600 is coupled with the mobile communication module 650, and the antenna 2 is coupled with the wireless communication module 660, so that the mobile phone 600 can communicate with the network and other devices through wireless communication technology. The wireless communication technology may include global system for mobile communications (GSM), general packet radio service (GPRS), code division multiple access (CDMA), wideband code Division multiple access (wideband code division multiple access, WCDMA), time division code division multiple access (time-division code division multiple access, TD-SCDMA), long term evolution (long term evolution, LTE), BT, GNSS, WLAN, NFC, FM, and/or IR technology, etc. The GNSS may include a global positioning system (GPS), a global navigation satellite system (GLONASS), a Beidou navigation satellite system (BDS), a quasi-zenith satellite system (quasi-zenith). satellite system, QZSS) and/or satellite based augmentation systems (SBAS).

The mobile phone 600 implements a display function through a GPU, a display screen 694, an application processor, and the like. The GPU is a microprocessor for image processing, and is connected to the display screen 694 and the application processor. The GPU is used to perform mathematical and geometric calculations for graphics rendering. Processor 610 may include one or more GPUs that execute program instructions to generate or alter display information.

Display screen 694 is used to display images, videos, and the like. Display screen 694 includes a display panel. The display panel can be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode or an active-matrix organic light-emitting diode (active-matrix organic light-emitting diode). , AMOLED), flexible light-emitting diode (flex light-emitting diode, FLED), Miniled, MicroLed, Micro-oLed, quantum dot light-emitting diodes (quantum dot light emitting diodes, QLED) and so on. In some embodiments, cell phone 600 may include 1 or N display screens 694, where N is a positive integer greater than 1.

The mobile phone 600 can realize the shooting function through the ISP, the camera 693, the video codec, the GPU, the display screen 694 and the application processor.

The ISP is used to process the data fed back by the camera 693 . For example, when taking a photo, the shutter is opened, the light is transmitted to the camera photosensitive element through the lens, the light signal is converted into an electrical signal, and the camera photosensitive element transmits the electrical signal to the ISP for processing, and converts it into an image visible to the naked eye. ISP can also perform algorithm optimization on image noise, brightness, and skin tone. ISP can also optimize the exposure, color temperature and other parameters of the shooting scene. In some embodiments, the ISP may be provided in the camera 693 .

Camera 693 is used to capture still images or video. The object is projected through the lens to generate an optical image onto the photosensitive element. The photosensitive element may be a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) phototransistor. The photosensitive element converts the optical signal into an electrical signal, and then transmits the electrical signal to the ISP to convert it into a digital image signal. The ISP outputs the digital image signal to the DSP for processing. DSP converts digital image signals into standard RGB, YUV and other formats of image signals. In some embodiments, the cell phone 600 may include 1 or N cameras 693 , where N is a positive integer greater than 1.

A digital signal processor is used to process digital signals, in addition to processing digital image signals, it can also process other digital signals. For example, when the mobile phone 600 selects a frequency point, the digital signal processor is used to perform Fourier transform on the energy of the frequency point, and so on.

Video codecs are used to compress or decompress digital video. Cell phone 600 may support one or more video codecs. In this way, the mobile phone 600 can play or record videos in various encoding formats, such as: moving picture experts group (moving picture experts group, MPEG) 1, MPEG2, MPEG3, MPEG4 and so on.

The external memory interface 620 can be used to connect an external memory card, such as a Micro SD card, to expand the storage capacity of the mobile phone 600 . The external memory card communicates with the processor 610 through the external memory interface 620 to realize the data storage function. For example to save files like music, video etc in external memory card.

Internal memory 621 may be used to store computer executable program code, which includes instructions. The processor 610 executes various functional applications and data processing of the mobile phone 600 by executing the instructions stored in the internal memory 621 . The internal memory 621 may include a storage program area and a storage data area. The storage program area may store an operating system, an application program required for at least one function (such as a sound playback function, an image playback function, a TCP acceleration function, etc.), and the like. The storage data area can store data (such as audio data, phone book, TCP messages, etc.) created during the use of the mobile phone 600, and the like. In addition, the internal memory 621 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, universal flash storage (UFS), and the like.

The mobile phone 600 can implement audio functions through an audio module 670, a speaker 670A, a receiver 670B, a microphone 670C, an earphone interface 670D, and an application processor. Such as music playback, recording, etc.

The audio module 670 is used for converting digital audio information into analog audio signal output, and also for converting analog audio input into digital audio signal. Audio module 670 may also be used to encode and decode audio signals. In some embodiments, the audio module 670 may be provided in the processor 610 , or some functional modules of the audio module 670 may be provided in the processor 610 .

Speaker 670A, also referred to as "horn", is used to convert audio electrical signals into sound signals. Mobile phone 600 can listen to music through speaker 670A, or listen to hands-free calls.

The receiver 670B, also referred to as "earpiece", is used to convert audio electrical signals into sound signals. When the mobile phone 600 answers a call or a voice message, the voice can be answered by placing the receiver 670B close to the human ear.

Microphone 670C, also called "microphone", "microphone", is used to convert sound signals into electrical signals. When making a call or sending a voice message, the user can make a sound by approaching the microphone 670C through the human mouth, and input the sound signal into the microphone 670C. The mobile phone 600 may be provided with at least one microphone 670C. In other embodiments, the mobile phone 600 may be provided with two microphones 670C, which can implement a noise reduction function in addition to collecting sound signals. In other embodiments, the mobile phone 600 may be further provided with three, four or more microphones 670C to collect sound signals, reduce noise, identify sound sources, and implement directional recording functions.

The headphone jack 670D is used to connect wired headphones. The earphone interface 670D may be a USB interface 630, or a 3.5mm open mobile terminal platform (OMTP) standard interface, a cellular telecommunications industry association of the USA (CTIA) standard interface.

The sensor module 680 may include a pressure sensor, a gyro sensor, an air pressure sensor, a magnetic sensor, an acceleration sensor, a distance sensor, a proximity light sensor, a fingerprint sensor, a temperature sensor, a touch sensor, an ambient light sensor, a bone conduction sensor, and the like.

Of course, the mobile phone 600 may also include a charging management module, a power management module, a battery, a button, an indicator, and one or more SIM card interfaces, etc., which are not limited in this embodiment of the present application.

The above FIG. 6 uses the mobile phone 600 as an example to illustrate the structure of the first device in the communication system. Next, the mobile phone 600 is used as an example to describe the communication protocol architecture that can be adopted by the first device.

The mobile phone 600 may include: an application layer, a transport layer, a network layer, a network interface layer, and an intermediate layer.

The application layer may include protocols such as file transfer protocol (FTP), simple mail transfer protocol (SMTP), and the transport layer may include TCP, user datagram protocol (UDP) and other protocols. ) and other protocols, the network layer may include protocols such as the Internet Protocol (IP) and the Internet Control Message Protocol (ICMP), and the network interface layer usually includes the data link layer and the physical layer. The data link layer further includes a media access control (media access control, MAC) layer. In practical applications, the network interface layer can be implemented by one or more of the following protocols: near field communication (NFC), radio frequency identification (RFID), bluetooth, 2G, 3G, 4G, 5G, Wi-Fi, ZigBee, long range radio (LORA), USB, RS485, etc. The intermediate layer is an independent protocol layer introduced in this embodiment of the present application, and may be located between the MAC layer and the TCP layer.

Exemplarily, as shown in (a) of FIG. 7 , the middle layer may be located at the network interface layer and be an upper layer of the MAC layer. Alternatively, as shown in (b) of FIG. 7 , the intermediate layer may be located at the network layer. As also shown in (c) of FIG. 7 , the intermediate layer may be located at the transport layer and be a lower layer of the TCP layer. As shown in (d) of FIG. 7 , the middle layer may be located between the network layer and the network interface layer. For another example, as shown in (e) of FIG. 7 , the intermediate layer may be located between the transport layer and the network layer.

In the embodiment of the present application, the middle layer may forward the packet from the lower layer (ie, the downlink packet) to the upper layer, and may also forward the packet from the upper layer (ie, the uplink packet) to the lower layer. Wherein, the intermediate layer further includes a buffer, and when forwarding the downlink packet or the uplink packet, the intermediate layer may also store the same packet as the downlink packet or the uplink packet in the buffer.

In this embodiment of the present application, when receiving a packet (including an uplink packet and a downlink packet), the intermediate layer may also parse the packet to analyze the TCP packet carried in the packet. 7, when the middle layer is located between the TCP layer and the IP layer in the network layer, the message received by the middle layer is a TCP message, and the middle layer can analyze the TCP message; when the middle layer is the IP layer When the lower layer is used, the packet received by the middle layer is an IP packet, and the middle layer needs to parse the header of the IP packet first, extract the TCP packet from the IP packet, and then analyze the TCP packet. In other words, the intermediate layer is located between the TCP layer and the IP layer, which can reduce the overhead of parsing packets by the intermediate layer, thereby improving processing efficiency.

Among them, other protocol layers below the middle layer may be referred to as other layers. For example, while the middle layer is at the network interface layer, the other layers include the MAC layer and the physical layer. For another example, when the middle layer is located between the transport layer and the network layer, the other layers include the network layer (eg, the IP layer), the MAC layer, and the physical layer.

The above-mentioned FIG. 7 uses the mobile phone 600 as an example to illustrate the communication protocol architecture that the first device can adopt. The following will describe in detail a communication method provided by the embodiments of the present application with reference to the accompanying drawings.

The communication method provided by the embodiment of the present application can be applied to the first device in the communication system shown in FIG. 4 . Taking the first device as a mobile phone, the second device as a server, the mobile phone as a client and the server as an example, please 8, the above communication method may include the following steps:

S801, the TCP layer sends a first data packet to the intermediate layer, and the intermediate layer receives the first data packet from the TCP layer.

The first data packet carries the first data. For example, the first data packet may come from the application layer of the mobile phone, and carry data generated by various application programs (such as WeChat, Douyin, etc.) in the mobile phone.

It should be understood that the intermediate layer buffers the first data packet from the TCP layer for retransmission. For a specific implementation manner, reference may be made to the relevant description in the following S805, which will not be repeated here.

As shown in (c) in FIG. 7 , taking the middle layer located at the transport layer and being the lower layer of the TCP layer as an example, the above-mentioned TCP layer sending the first data packet to the middle layer may include the following implementation manner: the TCP layer sends the middle layer to the middle layer. Send the first data message. When receiving the first data message, the intermediate layer copies the first data message, and stores the copied message in the buffer.

In addition, for the TCP layer, the middle layer and other layers in the mobile phone, reference may be made to the above description, which will not be repeated here.

S802, the intermediate layer sends the first data packet to other layers, and the other layers receive the first data packet from the intermediate layer.

As shown in (c) in FIG. 7 , continuing to take the example that the middle layer is located at the transport layer and is the lower layer of the TCP layer, the middle layer sends the first data packet to other layers, which may include the following implementation manner: the middle layer sends the first data packet to other layers. The network layer in sends the first data packet. When receiving the first data packet, the network layer processes the first data packet, for example, the IP layer in the network layer encapsulates the first data packet into an IP packet.

S803, the other layers send the first data packet to the server, and the server receives the first data packet from the other layers.

As shown in (c) in FIG. 7 , continuing to take the example that the intermediate layer is located in the transport layer and is the lower layer of the TCP layer, the other layers send the first data packet to the server, which may include the following embodiments: the network layer in the other layers A packet (such as the above IP packet) carrying the first data packet is sent to the MAC layer. The MAC layer encapsulates the packets from the network layer into data frames (carrying the first data packet), and sends these data frames to the server through the physical layer.

Since the wired link or wireless link of the network is not stable, the first data packet may be lost during network transmission. Therefore, the server may or may not receive the first data packet. data message. Among them, the packet loss includes: the packet is lost in the wired link or wireless link, bit error, etc. For example, when the packet has bit error, even if the server receives the packet, it cannot correctly parse the packet carried by the packet. data, thus confirming that the message is lost.

The way in which the server determines whether the first data packet is lost may include: starting from the time when the last packet of the first data packet is received, when the server does not receive the first data packet from the mobile phone when the receiving time threshold exceeds the threshold When the message is sent, the server determines that the first data message is lost.

In this embodiment of the present application, when the first data packet is not lost, the server may perform step 5 above to notify the mobile phone that the first data packet has been received by feeding back a confirmation packet to the mobile phone. When the first data packet is lost, the communication method shown in FIG. 8 may include the following steps:

S804, the server sends the first confirmation message to other layers, and the other layers receive the first confirmation message from the server.

The first confirmation message is used to instruct the TCP layer to retransmit the first data. In other words, the first acknowledgment message is a retransmission message.

Referring to the retransmission mechanism of TCP above, when the server determines that the first data packet is lost, the server may repeatedly feed back an acknowledgement packet carrying the same acknowledgement number to the mobile phone. For example, assuming that the sequence number of the first data message is = 100, the server may repeatedly feed back the first confirmation message with confirmation number = 100 to the mobile phone. That is to say, other layers and the middle layer can repeatedly receive the first confirmation message from the server. In addition, when the server repeatedly feeds back the confirmation message carrying the same confirmation number to the mobile phone, the confirmation message may also carry the SACK option to indicate which data packets are not received and which data packets are received. For example, suppose that the mobile phone continuously sends 5 data packets to the server, each data packet carries 100 bytes of data, the serial numbers are 100, 200, 300, 400, 500, and the serial numbers are 100, 300, 400 data If the packet is lost, and the data packets with serial numbers 200 and 500 are received by the server, the server can repeatedly feed back the first confirmation packet carrying the SACK option to the mobile phone. The SACK option is used to indicate that data packets with sequence numbers 100, 300, and 400 have not been received, and data packets with sequence numbers of 200 and 500 have been received. In this way, when the mobile phone receives the acknowledgment packet carrying the SACK option, it can determine that the data packets with serial numbers 100, 300, and 400 may be lost, so that the multiple data packets can be retransmitted at one time instead of one by one. , to avoid connection timeout on the server due to long waiting time, and improve the retransmission efficiency of the client.

S805, the other layers send the first confirmation message to the middle layer, and the middle layer receives the first confirmation message from the other layers.

Similar to the above S802 and S803, the above-mentioned other layers receive the first confirmation message from the server and send the first confirmation message to the intermediate layer, which may include the following embodiments: the physical layer in the other layers receives the first confirmation message from the server and carries the first confirmation message. Confirm the data of the message, parse the data, and send the parsed data to the MAC layer. When receiving data from the physical layer, the MAC layer is used to parse out the packets in the data (carrying the first confirmation packet), and send the first confirmation packet to the intermediate layer through the network layer.

During actual data transmission, other layers will not only send the first acknowledgment message to the middle layer, but also send other messages to the middle layer. In order to determine the first acknowledgment message, the intermediate layer may determine a plurality of acknowledgment messages with the same acknowledgment number in all messages from the server, and determine that the nth acknowledgment message in the plurality of acknowledgment messages is the first message , n can be an integer greater than or equal to 2. For details, refer to the following first judgment process.

The first judgment process may include: the middle layer parses each TCP message in the data from other layers, and when there are multiple acknowledgment messages with the same acknowledgment number in the parsed TCP message, determine the multiple identical acknowledgment messages. Among the confirmation messages, the nth confirmation message is the above-mentioned first confirmation message. In other words, when the retransmitted packets received from the server reach the first threshold, the intermediate layer determines these retransmitted packets as the first acknowledgment packets. The first threshold is an integer greater than or equal to 2. Optionally, the size of the first threshold is the same as the size of the retransmission threshold in the TCP retransmission mechanism.

Exemplarily, please refer to Table 1 below. Table 1 shows five TCP packets parsed by the middle layer when parsing each TCP packet in data from other layers. Among them, TCP packet 1-TCP packet 5 is parsed in the order of receiving time, TCP packet 1 is parsed the earliest time, TCP packet 5 is parsed the latest time, and TCP packet 1-TCP packet 5 are confirmation messages. The acknowledgment number of TCP message 1=100, the acknowledgment number of TCP message 2=200, the acknowledgment number of TCP message 3=300, the acknowledgment number of TCP message 4=300, and the acknowledgment number of TCP message 5=300. In other words, there are 3 acknowledgment packets with the same acknowledgment number in the parsed TCP packets, namely TCP packet 3, TCP packet 4, and TCP packet 5. Therefore, among these 5 TCP packets, TCP packet Message 4 and TCP message 5 are both the above-mentioned first confirmation messages.

Table 1

Confirmation Number acknowledgment number control bit TCP message 1 100 1 TCP message 2 200 1 TCP message 3 300 1 TCP message 4 300 1 TCP message 5 300 1

Since the middle layer can repeatedly receive acknowledgment packets from the server, optionally, when there are two acknowledgment packets with the same acknowledgment number in the parsed TCP packet, the middle layer will store the two acknowledgment packets with the same acknowledgment number. The second confirmation message in the confirmation message is determined to be the above-mentioned first confirmation message. That is, the above-mentioned n=2.

Taking Table 1 above as an example, when the middle layer parses out TCP packet 4, since TCP packet 4 is the same as TCP packet 3, and is the second acknowledgment packet in TCP packet 4 and TCP packet 3, Therefore, the TCP packet 4 is the above-mentioned first confirmation packet. Compared with retransmitting the lost packet after receiving the retransmission packets exceeding the retransmission threshold, in this embodiment of the present application, when the retransmission packet is received for the first time, the intermediate layer can immediately find the lost packet in the cache. , and retransmit, so that the lost packets can be retransmitted faster, and the data transmission efficiency of TCP can be improved.

In a possible embodiment, the middle layer may receive the fourth packet from the server. For example, when parsing each TCP packet in data from other layers, the middle layer determines the parsed confirmation packet as the fourth packet. Then, the intermediate layer can determine whether there is a fifth message in all the received confirmation messages, and the confirmation number of the fifth message is the same as that of the fourth message. If the fifth packet does not exist in all the confirmation packets received by the intermediate layer, the intermediate layer can send the fourth packet to the TCP layer; if there is a fifth packet in all the confirmation packets received by the intermediate layer, the intermediate layer The layer may not send the fourth packet to the TCP layer. In this way, the TCP layer can send the next data packet to the server according to the confirmation number in the fourth packet.

In this embodiment of the present application, when receiving a first confirmation message from another layer, the intermediate layer also generates a second data message carrying the above-mentioned first data according to the first confirmation message, and discards it (which may also be filtering or deleting ) first acknowledgment message. For example, assuming that the acknowledgment number of the first acknowledgment packet = 200, the intermediate layer may query the buffer for the data packet with the sequence number = 200, and determine the data packet as the second data packet. In this way, the middle layer can find the lost data in the buffer and retransmit it.

S806, the intermediate layer sends the second data packet to other layers, and the other layers receive the second data packet from the intermediate layer.

Similarly, for the process of the middle layer sending the second data packet to other layers, reference may be made to the above S802, and details are not repeated here.

S807, the other layers send the second data packet to the server, and the server receives the second data packet from the other layers.

Similarly, for the process of other layers sending the second data packet to the server, reference may be made to the above S803, and details are not repeated here.

It can be understood that, based on the above S801-S807, when receiving the instruction to retransmit the lost packet, the intermediate layer can not only retransmit the lost packet, but also filter the instruction to prevent the TCP layer from receiving the instruction. In this way, when the channel between the client and the server is not congested, when packets are occasionally lost, the TCP layer will not reduce the congestion window and reduce the packet sending rate.

In the embodiment of the present application, if the channel between the client and the server is congested and large-scale packet loss occurs, the above S805 may further include: within the first time period, receiving a first confirmation message with a different confirmation number When the number exceeds the congestion threshold, and/or the packet loss rate reaches the packet loss threshold, the middle layer sends the first message to the TCP layer. The first message is used to instruct the TCP layer to reduce the sending rate. For example, the first message includes multiple first acknowledgment packets with the same acknowledgment number. In this way, when the channel between the client and the server is congested, the middle layer can feed back the indication of retransmission of lost packets to the TCP layer, so that the TCP layer can reduce the congestion window, reduce the packet sending rate, and avoid the communication between the client and the server. further congestion of the inter-channel channel and improve the channel quality.

In order to improve the data transmission rate between the mobile phone and the server, optionally, continue to take the mobile phone as the sending end and the server as the receiving end as an example, please refer to FIG. 9 , in the process of establishing the connection between the mobile phone and the server, the above communication method includes the following A few steps:

S901, the TCP layer sends a first handshake packet to the intermediate layer, and the intermediate layer receives the first handshake packet from the TCP layer.

The first handshake message includes a window size and a window scaling factor, where the window size is N ₁ and the window scaling factor is S ₁ . Combining the above description of the window size and the window scaling factor, it can be known that the length of the receiving window of the mobile phone is N ₁ *2^S ₁ . In addition, for the mobile phone, the first handshake message is equivalent to carrying the downlink window.

When actually transmitting data, the TCP layer will not only send the first handshake message to the middle layer, but also send other TCP messages to the middle layer. Therefore, the middle layer can pass the second judgment process as follows. The first handshake message is determined in the text. Wherein, the second judgment process may include: the middle layer judges whether the TCP packet from the TCP layer is a SYN packet, and when the TCP packet from the TCP layer is a SYN packet, then determines that the SYN packet is the first handshake packet arts.

In this embodiment of the present application, when the middle layer receives the first handshake message from the TCP layer, the above S901 may further include: the middle layer generates a second handshake message according to the first handshake message. The difference between the second handshake message and the first handshake message is that the window size and window scaling factor are different. The window size in the second handshake message is N ₂ , the window scaling factor is S ₂ , and N ₂ * The value of 2^S ₂ is greater than or equal to the value of N ₁ *2^S ₁ . In other words, the length of the receiving window of the mobile phone indicated by the second handshake message ≥ the length of the receiving window of the mobile phone indicated by the first handshake message.

Exemplarily, when receiving the first handshake message from the TCP layer, the intermediate layer can modify the window size and the window scaling factor in the _first handshake message, and modify the window size N1 to _N2 , the window scaling factor S ₁ is modified to S ₂ , and the modified first handshake message is determined as the second handshake message. Wherein, N ₂ is greater than or equal to N ₁ , and/or S ₂ is greater than or equal to S ₁ .

S902, the middle layer sends a second handshake packet to other layers, and the other layers receive the second handshake packet from the middle layer.

S903, the other layers send the second handshake packet to the server, and the server receives the second handshake packet from the other layers.

In this embodiment of the present application, when receiving a second handshake packet from other layers, the server may generate a third handshake packet. The third handshake message includes a window size and a window scaling factor, where the window size is N ₃ and the window scaling factor is S ₃ . With reference to the above description of the window size and the window scaling factor, it can be known that the length of the receiving window of the server is N ₃ *2^S ₃ . In addition, for the mobile phone, the third handshake message is equivalent to carrying the uplink window.

S904, the server sends a third handshake packet to other layers, and the other layers receive the third handshake packet from the server.

S905, other layers send a third handshake packet to the intermediate layer, and the intermediate layer receives the third handshake packet from other layers.

When actually transmitting data, other layers will not only send the third handshake message to the middle layer, but also send other TCP messages to the middle layer. Therefore, the middle layer can pass the third judgment process as follows, in the TCP message from the TCP layer. The third handshake message is determined in the text. Wherein, the third judgment process may include: the middle layer judges whether the TCP packets from other layers are SYN packets, and when the TCP packets from other layers are SYN packets, then determine that the SYN packet is the third handshake packet arts.

Similar to the above S901, when receiving the third handshake packet from other layers, the above S905 may further include: the middle layer generates a fourth handshake packet according to the third handshake packet. The difference between the fourth handshake message and the third handshake message is that the window size and the window scaling factor are different. The window size in the fourth handshake message is N ₄ , the window scaling factor is S ₄ , and N ₄ * The value of 2^S ₄ is greater than or equal to the value of N ₃ *2^S ₃ . In other words, the length of the receiving window of the server indicated by the fourth handshake packet ≥ the length of the receiving window of the server indicated by the third handshake packet.

Exemplarily, when receiving the third handshake message from other layers, the middle layer can modify the window size and the window scaling factor in the third handshake message, and modify the window size N ₃ to N ₄ and the window scaling factor. S ₃ is modified to S ₄ , and the modified third handshake message is determined as the fourth handshake message. Wherein, N ₄ is greater than or equal to N ₃ , and/or S ₄ is greater than or equal to S ₃ .

S906, the middle layer sends a fourth handshake packet to the TCP layer, and the TCP layer receives the fourth handshake packet from the middle layer.

S907, the TCP sends the fifth handshake packet to the intermediate layer, and the intermediate layer receives the fifth handshake packet from the TCP layer.

The fifth handshake packet is used to indicate that the fourth handshake packet has been received from the server. For the implementation of the fifth handshake packet, reference may be made to the foregoing step 3, which will not be repeated here.

S908, the middle layer sends a fifth handshake packet to other layers, and the middle layer sends a fifth handshake packet to other layers.

S909, the other layers send the fifth handshake packet to the server, and the server receives the fifth handshake packet from the other layers.

The above S907-S909 are similar to steps 1-3. After executing S907-S909, the mobile phone and the server complete the TCP three-way handshake, and both the mobile phone and the server are in the ESTABLISHED state, and data can be exchanged.

Optionally, continuing to take the mobile phone as the sending end and the server as the receiving end as an example, during the data transmission process between the mobile phone and the server, the communication method shown in FIG. 9 further includes the following steps:

S910, the TCP layer sends a third data packet to the intermediate layer, and the intermediate layer receives the third data packet from the TCP layer.

Wherein, the third data packet includes a window size, and the window size is N ₅ . Combining the above description of the window size and the window scaling factor, it can be known that the length of the receiving window of the mobile phone is N ₅ *2^S ₅ . Wherein, _S5 may be the window scaling factor determined during the connection establishment process. In addition, for the mobile phone, the third data packet is equivalent to carrying the downlink window.

During actual data transmission, since the TCP layer will not only send the third data packet to the middle layer, but also other TCP packets to the middle layer, the middle layer can pass the fourth judgment process as follows, in the TCP from the TCP layer A third data message is determined in the message. Wherein, the fourth judgment process may include: the middle layer judges whether the TCP packet from the TCP layer is a data packet, and when the TCP packet from the TCP layer is a data packet, then determine that the data packet is the third data packet arts.

In this embodiment of the present application, when the third data packet from the TCP layer is received, the above S910 may further include: the intermediate layer generates a fourth data packet according to the third data packet. The difference between the fourth data packet and the third data packet is that the window size is different. The window size in the fourth data packet is N ₆ , and the value of N ₆ is greater than or equal to the value of N ₅ . In other words, the length of the receiving window of the mobile phone indicated by the fourth data packet ≥ the length of the receiving window of the mobile phone indicated by the third data packet.

Exemplarily, when receiving the third data packet from the TCP layer, the intermediate layer may modify the window size in the third data packet, and modify the window size N ₅ to N ₆ (N ₆ ≥ N ₅ ), The modified third data message is determined as the fourth data message.

S911, the middle layer sends a fourth data packet to other layers, and the other layers receive the fourth data packet from the middle layer.

S912, the other layers send a fourth data packet to the server, and the server receives the fourth data packet from the other layers.

In this embodiment of the present application, when receiving the fourth data packet from other layers, the server may generate a second confirmation packet. Wherein, the second confirmation message includes the window size, and the window size is N ₇ . With reference to the above description of the window size and the window scaling factor, it can be known that the length of the receiving window of the server is N ₇ *2^S ₅ . In addition, for the mobile phone, the second confirmation message is equivalent to carrying the uplink window.

S913, the server sends a second confirmation message to other layers, and the other layers receive the second confirmation message from the server.

S914, the other layers send the second confirmation message to the middle layer, and the middle layer receives the second confirmation message from the other layers.

During actual data transmission, other layers will not only send the second acknowledgment message to the middle layer, but also send other TCP messages to the middle layer. Therefore, the middle layer can pass the following fourth judgment process, in the TCP message from the TCP layer. The second confirmation message is determined in the text. Wherein, the fourth judgment process may include: the middle layer judges whether the TCP packet from other layers is an acknowledgement packet, and when the TCP packet from other layers is an acknowledgement packet, then determines that the acknowledgement packet is the second acknowledgement packet arts.

When receiving the second acknowledgment message from other layers, S914 may further include: the intermediate layer generates a third acknowledgment message according to the second acknowledgment message. The difference between the third acknowledgment message and the second acknowledgment message is that the window size is different, and the window size in the third acknowledgment message is N ₈ , and N ₈ is greater than or equal to N ₇ . In other words, the length of the receiving window of the server indicated by the third acknowledgment packet is greater than or equal to the length of the receiving window of the server indicated by the second acknowledgment packet.

Exemplarily, when receiving the second acknowledgment packet from another layer, the intermediate layer may modify the window size in the second acknowledgment packet, and modify the window size N ₇ to N ₈ (N ₈ ≥N ₇ ) , and determine the modified second confirmation message as the third confirmation message.

S915, the middle layer sends a third acknowledgment message to the TCP layer, and the TCP layer receives the third acknowledgment message from the middle layer.

It should be noted that, in S901-S915 shown in FIG. 9, the data interaction between the TCP layer and the middle layer, such as the first handshake message, the fourth handshake message, the fifth handshake message between the TCP layer and the middle layer For the interaction of the handshake message, the third data message, and the third confirmation message, reference may be made to S801 above. Data interaction between the middle layer and other layers, such as the second handshake message, the third handshake message, the fifth handshake message, the fourth data message, and the second acknowledgment message between the middle layer and other layers. For interaction, refer to S802 and S807 above. Data exchange between other layers and the server, such as the interaction of the second handshake message, the third handshake message, the fifth handshake message, the fourth data message and the second confirmation message between other layers and the server, Refer to S803 and S803 above. Therefore, the data interaction process of S901-S915 will not be repeated here.

The foregoing S901-S909 and S910-S915 may be implemented in combination, or may be implemented independently, which is not limited in this embodiment of the present application.

Based on the above S901-S903, S910-S912, it can be known that the middle layer can intercept the SYN message or data message sent by the mobile phone to the server, and enlarge the window size in the SYN message or data message, and/or, the window scaling factor, And send the enlarged window size, and/or the window scaling factor to the server. In this way, the server can be made to think that the receiving buffer of the mobile phone is sufficient, so that the server can send data to the mobile phone at a higher rate and increase the TCP transmission rate.

Similarly, based on the above S904-S906, S913-S915, the middle layer can intercept the SYN message or data message sent by the server to the mobile phone, and enlarge the window size in the SYN message or data message, and/or, the window The zoom factor, and the zoomed-in window size, and/or the window zoom factor, is sent to the phone. In this way, the TCP layer of the mobile phone can be made to think that the receiving buffer of the server is sufficient, so that the mobile phone can send data to the server at a higher rate and increase the TCP transmission rate.

In addition, for unified description, the length of the receiving window of the mobile phone indicated by the first handshake message and the third data message may be referred to as the length of the receiving window of the mobile phone before modification, the third handshake message and the second confirmation message. The length of the indicated server's receive window may be referred to as the length of the server's receive window before modification.

Optionally, when the mobile phone and the server are performing data exchange, in the downstream direction (that is, the mobile phone receives data packets from the server), when receiving data packets from the server through other layers, the intermediate layer can temporarily store these data packets. In addition, the middle layer can also send the data message from the server to the TCP layer according to the length of the receiving window of the mobile phone before the modification. In this way, the overload error of the receiving window of the TCP layer due to too much data can be avoided.

For example, in the downstream direction, suppose that due to sudden channel congestion or packet loss, etc., the server reduces the length of the send window to 100 bytes, while the length of the receive window of the mobile phone TCP layer is 500 bytes. In this case, in order to improve the sending rate of the server, the middle layer can send the amplified receiving window length of the TCP layer (for example, 1200 bytes) to the server by executing the above S901-S903 or S910-S912, so that the server can Increase the length of the send window, for example, the length of the server's send window is increased to 1000 bytes. The server then sends the message with a window length of 1000 bytes. The middle layer receives the message from the server with the window length of 1000 bytes, and sends the message from the server to the TCP layer with the length (500 bytes) of the receiving window of the mobile phone TCP layer before modification. In this way, the data sending rate of the server can be improved, and the overload error of the receiving window of the TCP layer caused by too much data can be avoided.

Correspondingly, in the uplink direction (that is, the mobile phone sends data packets to the server), when receiving data packets from the TCP layer, the intermediate layer can temporarily store these data packets in the buffer, and the intermediate layer can also press the above-mentioned data packets. The length of the receive window of the server before modification is used to send data packets from the TCP layer to the server. In this way, you can avoid overloading the server's receive window due to too much data.

For example, in the upstream direction, suppose that due to sudden channel congestion or packet loss, etc., the TCP layer of the mobile phone reduces the length of the send window to 100 bytes, while the length of the server's receive window is 500 bytes. In this case, in order to improve the sending rate of the TCP layer, the middle layer can send the amplified length of the server's receiving window (for example, 1200 bytes) to the TCP layer by executing the above S904-S906 or S913-S915, so that the The TCP layer increases the length of the send window, for example, the length of the send window of the TCP layer is increased to 1000 bytes. Then, the TCP layer sends the message with a window length of 1000 bytes. The middle layer receives the message from the TCP layer with the window length of 1000 bytes, and sends the message from the TCP layer to the server with the length of the server receiving window before modification (500 bytes). In this way, the sending rate of the TCP layer can be improved, and errors caused by overloading the receiving window of the server due to excessive data can be avoided.

Wherein, for unified description, the above-mentioned window size and window scaling factor may be referred to as window indication information, and the first handshake message, the third handshake message, the third data message, and the second confirmation message may be referred to as the second The messages, the second handshake message, the fourth handshake message, the fourth data message, and the third acknowledgment message may be referred to as third messages. The receiving window maintained by the client can be called the downlink window, and the receiving window maintained by the server can be called the uplink window.

Different services have different requirements for data transmission rate and transmission delay. For example, game services have high requirements for data transmission rate and transmission delay, while voice services have relatively low requirements for data transmission rate and transmission delay. In order to make the data transmission rate and transmission delay of different services more reasonable, optionally, the middle layer modifies the window indication information in the second packet according to the service corresponding to the second packet. In other words, the window indication information in the second packet is determined by the service corresponding to the second packet.

Exemplarily, please refer to FIG. 10, and continue to take the first device as a mobile phone as an example. The mobile phone includes user mode and kernel mode, the middle layer runs in the kernel mode, and the business runs in the user mode. The services may include game services, voice services, video services, and other services, and the services may be various application programs (application, APP) installed in the mobile phone.

The user state of the mobile phone may further include a processing application, the service may send the service ID and quintuple information to the processing application, and the processing application may receive the service ID and quintuple information. The quintuple information may include: source IP (internet protocol, Internet Protocol) address, source port, destination IP address, destination port and transport layer protocol type.

When receiving the ID and quintuple information from the service, the processing application can determine the length of the window corresponding to the service according to the service ID and quintuple information. The length of the window corresponding to the service may include the length of the uplink window and/or the length of the downlink window.

Taking the game service as an example, the processing application may include: a first correspondence between the ID of the game service and the requirement of quality of service (QoS), and a second correspondence between the requirement of QoS and the length of the window. When receiving the ID and quintuple information from the game service, the processing application can determine the QoS requirements of the game service according to the first correspondence and the ID of the game service, and then determine the QoS requirements of the game service according to the second correspondence and the game service. The length of the upstream window of the game service, and/or the length of the downstream window.

Optionally, the Qos may include throughput, and in the foregoing second correspondence, the throughput is proportional to the length of the window. That is, the greater the throughput, the greater the length of the window.

When the length of the window corresponding to the service is determined, the processing application can also send the length of the window corresponding to the service and the quintuple information to the middle layer, and the middle layer receives and converts the length and quintuple of the window corresponding to the service from the processing application. Group information is stored in the cache. The length of the window corresponding to the service and the quintuple information may be carried in the window modification message.

When receiving the second packet, the intermediate layer can determine the quintuple information corresponding to the second packet, and then determine the length of the window corresponding to the second packet according to the quintuple information corresponding to the second packet, and then determine the length of the window corresponding to the second packet according to the second packet. The length of the window corresponding to the message modifies the window indication information in the second message, and finally the modified second message is determined as the third message.

For example, with reference to the above FIG. 9 and Table 2 below, Table 2 shows the window length and quintuple information corresponding to some services stored in the middle layer. Taking the middle layer receiving the first handshake packet (carrying the downlink window) as an example, first the middle layer parses the quintuple information of the first handshake packet, assuming that the quintuple information of the first handshake packet is quintuple 2 , then the middle layer can determine the length of the downlink window corresponding to quintuple 2 as the length of the window corresponding to the first handshake message, and then can modify the window size in the first handshake message to N ₁₂ , and modify the window scaling factor As S ₁₂ , the modified first handshake message is finally determined as the second handshake message. Or, taking the middle layer receiving the third handshake packet (carrying the upstream window) as an example, first, the middle layer parses the quintuple information of the third handshake packet, assuming that the quintuple information of the third handshake packet is quintuple group 3, then the middle layer can determine the length of the uplink window corresponding to the quintuple 3 as the length of the window corresponding to the third handshake packet, and then can modify the window size in the third handshake packet to N ₁₃ , and the window is scaled The factor is modified to S ₁₃ , and finally the modified third handshake message is determined as the fourth handshake message.

Table 2

For another example, the above-mentioned FIG. 9 and Table 2 are combined. Taking the middle layer receiving the third data packet (carrying the downlink window) as an example, first, the middle layer parses the quintuple information of the third data packet, assuming that the quintuple information of the third data packet is quintuple 3 , then the intermediate layer can determine the length of the downlink window corresponding to the quintuple 3 as the length of the window corresponding to the third data packet, and then can modify the window size in the third data packet to N ₁₄ , and finally modify the modified The third data packet is determined to be the fourth data packet. Or, taking the middle layer receiving the second acknowledgment packet (carrying the upstream window) as an example, first, the middle layer parses the quintuple information of the second acknowledgment packet, assuming that the quintuple information of the second acknowledgment packet is quintuple information group 4, then the middle layer can determine the length of the uplink window corresponding to the quintuple 4 as the length of the window corresponding to the second acknowledgment packet, and then can modify the window size in the second acknowledgment packet to N ₁₅ , and finally set the The modified second confirmation message is determined to be the third confirmation message.

Based on the above Figure 10 and the corresponding description, the middle layer can modify the window indication information in the message according to the service, so as to modify the uplink window or downlink window corresponding to the service. For example, the uplink window or downlink window corresponding to the service with high throughput can be modified. When the window is increased, the uplink window or downlink window corresponding to the service with low throughput is reduced. In this way, the data transmission rate and transmission delay of different services can be made more reasonable.

The communication method provided by the embodiment of the present application has been described in detail above with reference to FIG. 8 to FIG. 10 . A communication device for executing the communication method provided by the embodiment of the present application will be described in detail below with reference to FIG. 11 and FIG. 12 .

Exemplarily, FIG. 11 is a first structural schematic diagram of a communication apparatus provided by an embodiment of the present application. As shown in FIG. 11 , the communication apparatus 1100 includes: a processing module 1101 and a transceiver module 1102 . The processing module 1101 includes the TCP layer and the middle layer of the communication device 1100, and the middle layer is the lower layer of the TCP layer. For convenience of explanation, FIG. 11 only shows the main components of the communication device.

In some embodiments, the communication apparatus 1100 can be applied to the communication system described above in FIG. 4 to perform the function of the first device in the communication system.

The middle layer of the communication apparatus 1100 is configured to use the transceiver module 1102 to receive a first packet from the second device, where the first packet instructs the TCP layer to retransmit the first data. The middle layer of the communication apparatus 1100 is further configured to discard the first packet, and use the transceiver module 1102 to send the first data to the second device.

In a possible design solution, the middle layer of the communication apparatus 1100 is further configured to buffer the packets from the TCP layer and/or the second device.

In a possible design solution, the middle layer of the communication apparatus 1100 is further configured to determine multiple acknowledgment packets with the same acknowledgment number in all packets from the second device. The middle layer of the communication device 1100 is further configured to determine the nth confirmation message in the plurality of confirmation messages as the first message, where n may be an integer greater than or equal to 2.

Optionally, n can be 2.

In a possible design solution, the first packet carries a selection acknowledgment SACK option, and the SACK option is used to instruct the TCP layer to retransmit the first data.

In a possible design solution, the middle layer of the communication device 1100 is further configured to receive, within the first time period, the number of first packets with different acknowledgment numbers that exceeds the congestion threshold, and/or the packet loss rate reaches the packet loss rate. When the threshold is reached, the transceiver module 1102 is used to send the first message to the TCP layer. The first message is used to instruct the TCP layer to reduce the sending rate.

In a possible design solution, the middle layer of the communication device 1100 is further configured to receive the second packet by using the transceiver module 1102 . The second packet may include first window indication information, where the first window indication information indicates the length of the first window. The middle layer of the communication device 1100 is also used for sending the third message by using the transceiver module 1102 . The third packet may include second window indication information, where the second window indication information indicates the length of the second window, and the length of the second window is greater than or equal to the length of the first window.

Optionally, the first window indication information may include a first window scaling factor field and a first window size field, and the second window indication information may include a second window scaling factor field and a second window size field. The length of the second window is greater than or equal to the length of the first window, and may include one or more of the following: the value of the second window scaling factor field is greater than or equal to the value of the first window scaling factor field, or, the second window size field The value of is greater than or equal to the value of the first window size field.

Optionally, the above-mentioned second window may be a receiving window of the second device. The middle layer of the communication apparatus 1100 is further configured to use the transceiver module 1102 to receive the second message from the second device. The middle layer of the communication device 1100 is further configured to send a third packet to the TCP layer by using the transceiver module 1102 , and the second window indication information is used to determine the sending window of the communication device 1100 .

Further, the middle layer of the communication apparatus 1100 is further configured to use the transceiver module 1102 to send a data packet to the second device according to the length of the first window indicated by the first window indication information.

Optionally, the above-mentioned second window may be a receiving window of the communication apparatus 1100 . The middle layer of the communication device 1100 is further configured to use the transceiver module 1102 to receive the second packet from the TCP layer. The middle layer of the communication apparatus 1100 is further configured to use the transceiver module 1102 to send a third packet to the second device, and the second window indication information is used to determine the sending window of the second device.

Further, the middle layer of the communication device 1100 is further configured to use the transceiver module 1102 to send the data packet to the TCP layer according to the indicated length of the first window.

Optionally, the above-mentioned second window indication information may be determined by the service corresponding to the second packet.

In a possible design solution, the middle layer of the communication apparatus 1100 is further configured to use the transceiver module 1102 to receive the fourth packet from the second device. The fourth message is an acknowledgement message. The middle layer of the communication device 1100 is further configured to determine whether there is a fifth message in all the confirmation messages received by the middle layer. The confirmation number of the fifth message is the same as the confirmation number of the fourth message. The middle layer of the communication device 1100 is further configured to use the transceiver module 1102 to send the fourth message to the TCP layer if the fifth message does not exist in all the confirmation messages received by the middle layer.

In a possible design solution, the middle layer is located between the TCP layer and the IP layer.

Optionally, the transceiver module 1102 may include a receiving module and a transmitting module (not shown in FIG. 11 ). The sending module is used to implement the sending function of the communication device 1100 , and the receiving module is used to implement the receiving function of the communication device 1100 .

Optionally, the communication apparatus 1100 may further include a storage module (not shown in FIG. 11 ), where the storage module stores programs or instructions. When the processing module 1101 executes the program or instruction, the communication apparatus 1100 can perform the function of the first device.

It should be understood that the processing module 1101 involved in the communication device 1100 may be implemented by a processor or a processor-related circuit component, and may be a processor or a processing unit; the transceiver module 1102 may be implemented by a transceiver or a transceiver-related circuit component, and may be a transceiver module Receiver or Transceiver Unit. In addition, the above-mentioned processing module 1101 may also be referred to as a processing unit 1101 , and the transceiver module 1102 may also be referred to as a transceiver unit 1102 .

It should be noted that the communication device 1100 may be the first device, or may be a chip (system) or other components or components provided in the above-mentioned first device, or a device including the first device, which is not limited in this application. .

In addition, for the technical effect of the communication apparatus 1100, reference may be made to the technical effect of the communication method described in the above method embodiments, which will not be repeated here.

Exemplarily, FIG. 12 is a second schematic structural diagram of a communication apparatus provided by an embodiment of the present application. The communication device may be the above-mentioned first device, or may be a chip (system) or other components or assemblies provided in the first device. As shown in FIG. 12 , the communication apparatus 1200 may include a processor 1201 . Optionally, the communication device 1200 may further include a memory 1202 and/or a transceiver 1203 . Wherein, the processor 1201 is coupled with the memory 1202 and the transceiver 1203, such as can be connected through a communication bus.

Each component of the communication device 1200 will be described in detail below with reference to FIG. 12 :

The processor 1201 is the control center of the communication device 1200, which may be one processor or a general term for multiple processing elements. For example, the processor 1201 is one or more central processing units (CPUs), may also be a specific integrated circuit (application specific integrated circuit, ASIC), or is configured to implement one or more embodiments of the present application An integrated circuit, for example: one or more microprocessors (digital signal processors, DSP), or, one or more field programmable gate arrays (field programmable gate array, FPGA).

Optionally, the processor 1201 may execute various functions of the communication device 1200 by running or executing software programs stored in the memory 1202 and calling data stored in the memory 1202 .

In a specific implementation, as an embodiment, the processor 1201 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG. 12 .

In a specific implementation, as an embodiment, the communication apparatus 1200 may also include multiple processors, for example, the processor 1201 and the processor 1204 shown in FIG. 12 . Each of these processors can be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). A processor herein may refer to one or more devices, circuits, and/or processing cores for processing data (eg, computer program instructions).

The memory 1202 is used to store the software program for executing the solution of the present application, and is controlled and executed by the processor 1201. For the specific implementation, reference may be made to the above method embodiments, which will not be repeated here.

Alternatively, memory 1202 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, random access memory (RAM), or a random access memory (RAM) or other type of static storage device that can store information and instructions. Other types of dynamic storage devices for instructions, also can be electrically erasable programmable read-only memory (electrically erasable programmable read-only memory, EEPROM), compact disc read-only memory (CD-ROM) or other optical disk storage , optical disc storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), magnetic disk storage medium or other magnetic storage device, or capable of carrying or storing desired program code in the form of instructions or data structures and Any other medium that can be accessed by a computer, but is not limited to this. The memory 1202 may be integrated with the processor 1201, or may exist independently, and be coupled to the processor 1201 through an interface circuit (not shown in FIG. 12) of the communication device 1200, which is not specifically limited in this embodiment of the present application.

The transceiver 1203 is used for communication with other communication devices. For example, the communication device 1200 is a client and the transceiver 1203 can be used to communicate with the server.

Optionally, the transceiver 1203 may include a receiver and a transmitter (not shown separately in FIG. 12). Among them, the receiver is used to realize the receiving function, and the transmitter is used to realize the sending function.

Optionally, the transceiver 1203 may be integrated with the processor 1201, or may exist independently, and be coupled to the processor 1201 through an interface circuit (not shown in FIG. 12 ) of the communication device 1200, which is not made in this embodiment of the present application Specific restrictions.

It should be noted that the structure of the communication device 1200 shown in FIG. 12 does not constitute a limitation on the communication device, and an actual communication device may include more or less components than those shown in the figure, or combine some components, or Different component arrangements.

In addition, for the technical effect of the communication apparatus 1200, reference may be made to the technical effect of the communication method described in the above method embodiments, which will not be repeated here.

This embodiment also provides a communication system. The communication system includes one or more first devices and one or more second devices. The first device includes a TCP layer and an intermediate layer, and the intermediate layer is a lower layer of the TCP layer.

In the description of this application, unless stated otherwise, "at least one" means one or more, and "plurality" means two or more. In addition, in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish the same or similar items with basically the same function and effect. Those skilled in the art can understand that the words "first", "second" and the like do not limit the quantity and execution order, and the words "first", "second" and the like are not necessarily different.

In addition, in the embodiments of the present application, words such as "exemplarily" and "for example" are used to represent examples, illustrations or illustrations. Any embodiment or design described in this application as "exemplary" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of the word example is intended to present a concept in a concrete way.

In the embodiments of the present application, sometimes _a subscript such as W1 may be mistakenly written in a non-subscript form such as W1. When the difference is not emphasized, the meaning to be expressed is the same.

It should be understood that the processor in the embodiments of the present application may be a central processing unit (central processing unit, CPU), and the processor may also be other general-purpose processors, digital signal processors (digital signal processors, DSP), application-specific integrated circuits ( application specific integrated circuit, ASIC), off-the-shelf programmable gate array (field programmable gate array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

It should also be understood that the memory in the embodiments of the present application may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically programmable Erase programmable read-only memory (electrically EPROM, EEPROM) or flash memory. Volatile memory may be random access memory (RAM), which acts as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory Access memory (synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (double data rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (enhanced SDRAM, ESDRAM), synchronous connection dynamic random access Memory (synchlink DRAM, SLDRAM) and direct memory bus random access memory (direct rambus RAM, DR RAM).

The above embodiments may be implemented in whole or in part by software, hardware (eg, circuits), firmware, or any other combination. When implemented in software, the above-described embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer may be a general purpose computer, special purpose computer, computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server or data center Transmission to another website site, computer, server or data center by wire (eg, infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, a data center, or the like that contains one or more sets of available media. The usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVDs), or semiconductor media. The semiconductor medium may be a solid state drive.

It should be understood that the term "and/or" in this document is only an association relationship to describe associated objects, indicating that there can be three kinds of relationships, for example, A and/or B, which can mean that A exists alone, and A and B exist at the same time , there are three cases of B alone, where A and B can be singular or plural. In addition, the character "/" in this document generally indicates that the related objects before and after are an "or" relationship, but may also indicate an "and/or" relationship, which can be understood with reference to the context.

In this application, "at least one" means one or more, and "plurality" means two or more. "At least one item(s) below" or similar expressions thereof refer to any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one item (a) of a, b, or c can represent: a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, c may be single or multiple .

It should be understood that, in various embodiments of the present application, the size of the sequence numbers of the above-mentioned processes does not mean the sequence of execution, and the execution sequence of each process should be determined by its functions and internal logic, and should not be dealt with in the embodiments of the present application. implementation constitutes any limitation.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described systems, devices and units may refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as independent products, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, removable hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk and other media that can store program codes .

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited to this. should be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims (31)

1. a communication method, is characterized in that, is applied to first equipment, described first equipment comprises transmission control protocol TCP layer and middle layer, described middle layer is the lower layer of described TCP layer, and described method comprises: the middle layer receives the first packet from the second device; the first packet instructs the TCP layer to retransmit the first data; The intermediate layer sends the first data to the second device, and discards the first packet. 2. The method according to claim 1, wherein before the middle layer receives the first packet from the second device, the method further comprises: The intermediate layer buffers the packets from the TCP layer and/or the second device. 3. The method according to claim 1 or 2, wherein the intermediate layer receives the first packet from the second device, comprising: determining, by the intermediate layer, multiple confirmation messages with the same confirmation number in all messages from the second device; The middle layer determines that the nth confirmation message in the plurality of confirmation messages is the first message, and n is an integer greater than or equal to 2. 4. The method according to any one of claims 1-3, wherein the method further comprises: receiving, by the middle layer, a second packet, where the second packet includes first window indication information, and the first window indication information indicates the length of the first window; The middle layer sends a third packet, the third packet includes second window indication information, the second window indication information indicates the length of the second window, and the length of the second window is greater than or equal to the first window. The length of a window. 5. The method according to claim 4, wherein the first window indication information comprises a first window scaling factor field and a first window size field; the second window indication information comprises a second window scaling factor field and the second window size field; The length of the second window is greater than or equal to the length of the first window, including one or more of the following: The value of the second window scaling factor field is greater than or equal to the value of the first window scaling factor field; The value of the second window size field is greater than or equal to the value of the first window size field. 6. The method according to claim 4 or 5, wherein the second window is a receiving window of the second device; The middle layer receives the second packet, including: receiving, by the intermediate layer, the second packet from the second device; The middle layer sends a third packet, including: The middle layer sends the third packet to the TCP layer, and the second window indication information is used to determine the sending window of the first device. 7. The method according to claim 6, wherein the method further comprises: The middle layer sends a data packet to the second device according to the length of the first window indicated by the first window indication information. 8. The method according to claim 4 or 5, wherein the second window is a receiving window of the first device; The middle layer receives the second packet, including: the middle layer receives the second packet from the TCP layer; The middle layer sends a third packet, including: The middle layer sends the third packet to the second device, and the second window indication information is used to determine the sending window of the second device. 9. The method according to claim 8, wherein the method further comprises: The middle layer sends a data packet to the TCP layer according to the length of the first window indicated by the first window indication information. 10 . The method according to claim 4 , wherein the second window indication information is determined by a service corresponding to the second packet. 11 . 11. The method according to any one of claims 1-10, wherein the method further comprises: the middle layer receives a fourth message from the second device; the fourth message is an acknowledgement message; The middle layer judges whether there is a fifth message in all the confirmation messages received by the middle layer; the confirmation number of the fifth message is the same as the confirmation number of the fourth message; If the fifth packet does not exist in all the confirmation packets received by the intermediate layer, the intermediate layer sends the fourth packet to the TCP layer. 12. The method according to any one of claims 1-11, wherein the intermediate layer is located between the TCP layer and the Internet Protocol (IP) layer. 13. The method according to any one of claims 1-12, wherein the method further comprises: During the first period of time, the number of received first packets with different acknowledgment numbers exceeds the congestion threshold, and/or when the packet loss rate reaches the packet loss threshold, the middle layer sends the first message to the TCP layer; The first message is used to instruct the TCP layer to reduce the sending rate. 14. The method according to any one of claims 1-13, wherein the first packet carries a selection acknowledgement SACK option, and the SACK option is used to indicate retransmission of the first data. 15. A communication device, characterized in that: a processing module and a transceiver module; the processing module comprises a transmission control protocol TCP layer and an intermediate layer of the communication device, and the intermediate layer is a lower layer of the TCP layer; wherein, an intermediate layer of the communication device, configured to use the transceiver module to receive a first message from a second device; the first message instructs the TCP layer to retransmit the first data; The middle layer of the communication apparatus is further configured to discard the first packet, and use the transceiver module to send the first data to the second device. The apparatus according to claim 15, wherein the middle layer of the communication apparatus is further configured to buffer packets from the TCP layer and/or the second device. 17. The device according to claim 15 or 16, wherein the middle layer of the communication device is further configured to determine a plurality of confirmation messages with the same confirmation number in all messages from the second device; The middle layer of the communication device is further configured to determine that the nth confirmation message in the plurality of confirmation messages is the first message, where n is an integer greater than or equal to 2. 18. The device according to any one of claims 15-17, wherein the middle layer of the communication device is further configured to use the transceiver module to receive a second packet, wherein the second packet includes first window indication information, where the first window indication information indicates the length of the first window; The middle layer of the communication device is further configured to use the transceiver module to send a third message, where the third message includes second window indication information, and the second window indication information indicates the length of the second window, so The length of the second window is greater than or equal to the length of the first window. 19. The apparatus according to claim 18, wherein the first window indication information comprises a first window scaling factor and a first window size; the second window indication information comprises a second window scaling factor and a second window scaling factor window size; The length of the second window is greater than or equal to the length of the first window, including one or more of the following: the second window scaling factor is greater than or equal to the first window scaling factor; The second window size is greater than or equal to the first window size. 20. The apparatus according to claim 18 or 19, wherein the second window is a receiving window of the second device; The middle layer of the communication device is further configured to use the transceiver module to receive the second message from the second device; The middle layer of the communication device is further configured to use the transceiver module to send the third packet to the TCP layer, and the second window indication information is used to determine a sending window of the communication device. 21. The apparatus according to claim 20, wherein the middle layer of the communication apparatus is further configured to send data to the second device according to the length of the first window indicated by the first window indication information message. 22. The device according to claim 18 or 19, wherein the second window is a receiving window of the communication device; The middle layer of the communication device is further configured to receive the second message from the TCP layer by using the transceiver module; The middle layer of the communication apparatus is further configured to use the transceiver module to send the third packet to the second device, and the second window indication information is used to determine a sending window of the second device. 23. The device according to claim 22, wherein the middle layer of the communication device is further configured to send a datagram to the TCP layer according to the length of the first window indicated by the first window indication information arts. 24. The apparatus according to any one of claims 18-23, wherein the second window indication information is determined by a service corresponding to the second packet. 25. The device according to any one of claims 15-24, wherein the middle layer of the communication device is further configured to use the transceiver module to receive a fourth message from the second device; The fourth message is a confirmation message; The middle layer of the communication device is further configured to judge whether there is a fifth message in all the confirmation messages received by the middle layer; the confirmation number of the fifth message and the confirmation number of the fourth message same; The middle layer of the communication device is further configured to send the fourth message to the TCP layer by using the transceiver module if the fifth message does not exist in all the confirmation messages received by the middle layer arts. 26. The apparatus according to any one of claims 15-25, wherein the intermediate layer is located between the TCP layer and the Internet Protocol (IP) layer. 27. The device according to any one of claims 15-26, wherein the middle layer of the communication device is further configured to receive the number of first packets with different acknowledgment numbers in the first time period When the congestion threshold is exceeded, and/or the packet loss rate reaches the packet loss threshold, the transceiver module is used to send a first message to the TCP layer; the first message is used to instruct the TCP layer to reduce the sending rate. 28. The apparatus according to any one of claims 15-27, wherein the first packet carries a selection acknowledgment SACK option, and the SACK option is used to indicate retransmission of the first data. 29. A communication device, comprising: a processor coupled to a memory; The processor is configured to execute the computer program stored in the memory, so that the communication apparatus executes the communication method according to any one of claims 1-14. 30. A computer-readable storage medium, characterized in that the computer-readable storage medium comprises a computer program or instruction, which, when the computer program or instruction is executed on a computer, causes the computer to perform the method according to claim 1- The communication method of any one of 14. 31. A computer program product, characterized in that the computer program product comprises: a computer program or instruction that, when the computer program or instruction is run on a computer, causes the computer to perform any one of claims 1-14. A method of communication as described.

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