PACKET TRANSMISSION METHOD, TERMINAL, NETWORK DEVICE, AND COMMUNICATIONS SYSTEM

• US 20190319889A1
• Filed: 06/27/2019
• Published: 10/17/2019
• Est. Priority Date: 12/30/2016
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: ZHANG, Zhong, DENG, Yu, YANG, Neng, WEI, Jianguo
• Granted Patent: US 10,924,421 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/27 Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers
• CPC Class Codes: H04L 47/37 Slow start
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365

Abstract

A packet transmission method and related apparatus are disclosed. A transmit end retransmits a first packet to a receive end and decreases a congestion window and a slow start threshold upon determining that the first packet has been lost. The receive end sends an ACK in response to the retransmitted first packet to the transmit end on receipt of the retransmitted first packet for the first time, where the ACK contains a proactively constructed DSACK option for informing the transmit end that the first packet has been received repeatedly. The transmit end therefore compensates the congestion window and/or the slow start threshold.

Claims

1. A packet transmission method, comprising:

receiving, by a terminal, a retransmitted packet, wherein the retransmitted packet is sent by a server after the server determines that a sent first packet has been lost, and a sequence number of the retransmitted packet is the same as a sequence number carried in the first packet; and

upon receiving the retransmitted packet for the first time, sending, by the terminal to the server, a first acknowledgment packet used to respond to the retransmitted packet received for the first time, wherein the first acknowledgment packet comprises a repetition indication field, and the repetition indication field is used to indicate that the first packet has been received repeatedly, and is used to trigger the server to increase at least one of a congestion window size or a slow start threshold.

2. The method according to claim 1, wherein the first acknowledgment packet is sent by the terminal when the terminal receives for the first time a packet whose sequence number is the same as that of the first packet.

3. The method according to claim 1, wherein the first acknowledgment packet further comprises a SACK option, and the SACK option is used to indicate sequence number information of a packet that has been received by the terminal.

4. The method according to claim 3, wherein the repetition indication field comprises the sequence number of the first packet, and the repetition indication field is located in a 1^st block of the SACK option in the first acknowledgment packet.

5. The method according to claim 3, wherein the repetition indication field comprises the sequence number of the first packet, the repetition indication field is located in a DSACK block, and the DSACK block is used to report a packet repeatedly received by the terminal to the server.

6. The method according to claim 1, wherein further comprising:

establishing, by the terminal, a TCP connection to the server by using a wireless network, wherein the wireless network comprises at least one access point.

7. A terminal, comprising an application processor, a memory, and a communications subsystem, wherein the memory stores a protocol stack program;

the communications subsystem is configured to receive a retransmitted packet, wherein the retransmitted packet is sent by a server after the server determines that a sent first packet has been lost, and a sequence number of the retransmitted packet is the same as a sequence number carried in the first packet;

the application processor runs the protocol stack program in the memory, so as to;

when the communications subsystem receives the retransmitted packet for the first time, construct a first acknowledgment packet used to respond to the retransmitted packet received for the first time, wherein the first acknowledgment packet comprises a repetition indication field, and the repetition indication field is used to indicate that the first packet has been received repeatedly, and is used to trigger the server to increase at least one of a congestion window size or a slow start threshold; and

the communications subsystem is further configured to send the constructed first acknowledgment packet.

8. The terminal according to claim 7, wherein the communications subsystem is specifically configured to send the constructed first acknowledgment packet when a packet whose sequence number is the same as that of the first packet is received for the first time.

9. The terminal according to claim 7, wherein the first acknowledgment packet further comprises a SACK option, and the SACK option is used to indicate sequence number information of a packet that has been received by the terminal.

10. The terminal according to claim 9, wherein the repetition indication field comprises the sequence number of the first packet, and the repetition indication field is located in a 1^st block of the SACK option in the first acknowledgment packet.

11. The terminal according to claim 7, wherein the terminal connects to a wireless network and establishes a TCP connection to the server, by using at least one access point.

12. A network device, configured to forward a packet between a transmit end and a receive end, wherein the network device comprises a processing circuit, a communications interface, and a storage medium;

the communications interface is configured to;

receive a retransmitted packet sent by the transmit end to the receive end, forward the retransmitted packet to the receive end, and receive a first acknowledgment packet of the receive end in response to the retransmitted packet, wherein the retransmitted packet is sent by the transmit end after the transmit end determines that a sent first packet has been lost, and a sequence number of the retransmitted packet is the same as a sequence number carried in the first packet; and

the first acknowledgment packet is sent by the receive end when the receive end receives the retransmitted packet for the first time;

the storage medium stores a protocol stack program, and the processing circuit is adapted to execute the protocol stack program stored in the storage medium, so as to;

add a repetition indication field to the first acknowledgment packet to obtain a second acknowledgment packet, wherein the repetition indication field is used to indicate that the first packet has been received repeatedly, and is used to trigger the transmit end to increase at least one of a congestion window size or a slow start threshold; and

the communications interface is further configured to send the second acknowledgment packet.

13. The network device according to claim 12, wherein the first acknowledgment packet is sent by the receive end when the receive end receives for the first time a packet whose sequence number is the same as that of the first packet.

14. The network device according to claim 12, wherein the first acknowledgment packet and the second acknowledgment packet both further comprise a SACK option, and the SACK option is used to indicate sequence number information of a packet that has been received by the receive end.

15. The network device according to claim 14, wherein the repetition indication field comprises the sequence number of the first packet, and the repetition indication field is located in a 1^st block of the SACK option in the second acknowledgment packet.

16. The network device according to claim 14, wherein the network device is an access point, and the receive end connects to a wireless network and establishes a TCP connection to the transmit end, by using the network device.