# US 12,225,090 B2 · Packet transmission method, communication apparatus, and communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,225,090 B2 - Document ID: US12225090B2 - Status: Granted - Kind: B2 - Application number: 18/344,655 - Filed: 2023-06-29 - Published: 2023-12-28 - Granted: 2025-02-11 - Earliest claimed: 2019-11-29 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Fang Yu; Yan Li; Ao Lei - Web page: https://patentgrep.com/patent/US12225090B2 ## CPC - H04L 67/148: Migration or transfer of sessions - H04W 36/12: Reselecting a serving backbone network switching or routing node - H04L 45/655: Interaction between route computation entities and forwarding entities, e.g. for route determination or for flow table update - H04L 63/0281: {Proxies} - H04L 63/166: {at the transport layer} - H04L 69/14: Multichannel or multilink protocols - H04W 36/16: Performing reselection for specific purposes - H04W 40/36: due to handover - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Embodiments of this application provide a packet transmission method, a communication apparatus, and a communication system. A target transport layer proxy network element establishes a fourth transport layer connection based on a first context of a source transport layer proxy network element, where the first context is a context about packet transmission of the source transport layer proxy network element on a first path. If the target transport layer proxy network element receives first indication information, and the first indication information indicates that application context migration between a first application server and a second application server is completed, the target transport layer proxy network element performs transport layer processing on a packet on a second path based on a second context of the target transport layer proxy network element, and transmits, on the second path, a packet obtained through the transport layer processing. Hence, a packet loss can be avoided. ## Claims ### Claim 1 A communication apparatus, wherein the communication apparatus is a target transport layer proxy network element or is a chip for the target transport layer proxy network element, and wherein the communication apparatus comprises a processor, wherein the processor is coupled to a memory, and the memory is configured to store a program or instructions; and when the program or the instructions is/are executed by the processor, the apparatus is enabled to perform operations comprising: establishing a fourth transport layer connection based on a first context of a source transport layer proxy network element, wherein the first context is a context about packet transmission of the source transport layer proxy network element on a first path; and based on receiving first indication information, and the first indication information being used to indicate that application context migration between a first application server and a second application server is completed, performing transport layer processing on a packet on a second path based on a second context of the target transport layer proxy network element, and transmitting, on the second path, a packet obtained through the transport layer processing, wherein the second path comprises a third transport layer connection and the fourth transport layer connection; the second context is determined based on the first context and the fourth transport layer connection; when the application context migration is being performed, packet transmission between the first application server and a transport layer proxy network element is stopped; and the transport layer proxy network element comprises the source transport layer proxy network element or the target transport layer proxy network element, wherein the first path is a path established between a terminal device and the first application server, the first path comprises a first transport layer connection and a second transport layer connection, the first transport layer connection is a transport layer connection between the source transport layer proxy network element and the terminal device, the second transport layer connection is a transport layer connection between the source transport layer proxy network element and the first application server, the third transport layer connection is a transport layer connection between the target transport layer proxy network element and the terminal device, and the fourth transport layer connection is a transport layer connection between the target transport layer proxy network element and the second application server. ### Claim 2 (depends on 1) The communication apparatus according to claim 1, wherein when the program or the instructions is/are executed by the processor, the apparatus is enabled to perform the operations further comprising: receiving a first uplink transmission control protocol (TCP) packet and a first downlink multipath transmission control protocol (MPTCP) packet from the source transport layer proxy network element, wherein the first uplink TCP packet is a packet that is received by the source transport layer proxy network element but that is not sent to the first application server, and the first downlink MPTCP packet is a packet that is received by the source transport layer proxy network element but that is not sent to the terminal device; encapsulating the first uplink TCP packet into a first uplink MPTCP packet based on the second context, and sending the first uplink MPTCP packet to the second application server through the fourth transport layer connection; and encapsulating the first downlink MPTCP packet into a first downlink TCP packet based on the second context of the target transport layer proxy network element, and sending the first downlink TCP packet to the terminal device through the third transport layer connection. ### Claim 3 (depends on 1) The communication apparatus according to claim 1, wherein when the program or the instructions is/are executed by the processor, the apparatus is enabled to perform the operations further comprising: receiving a notification message from a session management network element, wherein the notification message is used to indicate that the target transport layer proxy network element is to start performing transport layer processing on a packet, and the notification message comprises the first context. ### Claim 4 (depends on 1) The communication apparatus according to claim 1, wherein when the program or the instructions is/are executed by the processor, the apparatus is enabled to perform the operations further comprising: before receiving first indication information, performing transport layer processing on a packet on a third path based on the first context, and transmitting, on the third path, a packet obtained through the transport layer processing, wherein the third path is a path established between the terminal device and the first application server, the third path comprises the third transport layer connection and a fifth transport layer connection, the fifth transport layer connection is a transport layer connection between the target transport layer proxy network element and the first application server, and the fifth transport layer connection passes through the source transport layer proxy network element; and based on receiving second indication information sent by the first application server, stopping sending data to the first application server, wherein the second indication information is sent when the first application server is to start performing application context migration between the first application server and the second application server. ### Claim 5 (depends on 4) The communication apparatus according to claim 4, wherein when the program or the instructions is/are executed by the processor, the apparatus is enabled to perform the operations further comprising: receiving a second uplink transmission control protocol (TCP) packet and a second downlink multipath transmission control protocol (MPTCP) packet from the source transport layer proxy network element, wherein the second uplink TCP packet is a packet that is received by the source transport layer proxy network element but that is not sent to the first application server, and the second downlink MPTCP packet is a packet that is received by the source transport layer proxy network element but that is not sent to the terminal device; encapsulating the second uplink TCP packet into a second uplink MPTCP packet based on the first context, and sending the second uplink MPTCP packet to the first application server through the fifth transport layer connection via the source transport layer proxy network element; and encapsulating the second downlink MPTCP packet into a second downlink TCP packet based on the first context, and sending the second downlink TCP packet to the terminal device through the third transport layer connection. ### Claim 6 (depends on 1) The communication apparatus according to claim 1, wherein the first context comprises a first transport layer connection parameter and a second transport layer connection parameter, and the first transport layer connection parameter and the second transport layer connection parameter are used to perform transport layer processing; or the first context comprises a first transport layer connection parameter, a first transmission state parameter, a second transport layer connection parameter, and a second transmission state parameter, the first transport layer connection parameter and the second transport layer connection parameter are used to perform transport layer processing, the first transmission state parameter is used to indicate a packet transmission state of the first transport layer connection, and the second transmission state parameter is used to indicate a packet transmission state of the second transport layer connection. ### Claim 7 A communication apparatus, wherein the communication apparatus is a source transport layer proxy network element or is a chip for the source transport layer proxy network element, and wherein the communication apparatus comprises a processor, wherein the processor is coupled to a memory, and the memory is configured to store a program or instructions; and when the program or the instructions is/are executed by the processor, the apparatus is enabled to perform operations comprising: based on receiving third indication information, stopping performing transport layer processing on a packet on a first path based on a first context of the source transport layer proxy network element, wherein the first context is a context about packet transmission of the source transport layer proxy network element on the first path, wherein the first context is used by a target transport layer proxy network element to establish a fourth transport layer connection; based on receiving first indication information, the target transport layer proxy network element performs transport layer processing on a packet on a second path based on a second context of the target transport layer proxy network element; the second context is determined based on the first context and a context of the fourth transport layer connection; the first indication information is used to indicate that application context migration between a first application server and a second application server is completed; when the application context migration is being performed, packet transmission between the first application server and a proxy network element is stopped; and the proxy network element comprises the source transport layer proxy network element or the target transport layer proxy network element; and the first path is a path established between a terminal device and the first application server, the first path comprises a first transport layer connection and a second transport layer connection, the first transport layer connection is a transport layer connection between the source transport layer proxy network element and the terminal device, the second transport layer connection is a transport layer connection between the source transport layer proxy network element and the first application server, the second path comprises a third transport layer connection and the fourth transport layer connection, the third transport layer connection is a transport layer connection between the target transport layer proxy network element and the terminal device, and the fourth transport layer connection is a transport layer connection between the target transport layer proxy network element and the second application server. ### Claim 8 (depends on 7) The communication apparatus according to claim 7, wherein when the program or the instructions is/are executed by the processor, the apparatus is enabled to perform the operations further comprising: sending a migration complete instruction to a session management network element, wherein the migration complete instruction is used to indicate that the source transport layer proxy network element has stopped performing transport layer processing on a packet and that the target transport layer proxy network element has started performing transport layer processing on a packet, and the migration complete instruction is used by the session management network element to trigger the application context migration between the first application server and the second application server. ### Claim 9 (depends on 7) The communication apparatus according to claim 7, wherein when the program or the instructions is/are executed by the processor, the apparatus is enabled to perform the operations further comprising: before the stopping performing transport layer processing on a packet on a first path based on a first context of the source transport layer proxy network element, detecting whether a third uplink packet is an uplink multipath transmission control protocol (MPTCP) packet, wherein the third uplink packet is an uplink packet from the target transport layer proxy network element to the first application server via the source transport layer proxy network element; and determining that the third uplink packet is the uplink MPTCP packet. ### Claim 10 (depends on 7) The communication apparatus according to claim 7, wherein when the program or the instructions is/are executed by the processor, the apparatus is enabled to perform the operations further comprising: sending a first uplink transmission control protocol (TCP) packet and a first downlink multipath transmission control protocol (MPTCP) packet to the target transport layer proxy network element for transport layer processing, wherein the first uplink TCP packet is a packet that is received by the source transport layer proxy network element but that is not sent to the first application server, and the first downlink MPTCP packet is a packet that is received by the source transport layer proxy network element but that is not sent to the terminal device. ### Claim 11 (depends on 10) The communication apparatus according to claim 10, wherein when the program or the instructions is/are executed by the processor, the apparatus is enabled to perform the operations further comprising: before the sending a first uplink TCP packet and a first downlink MPTCP packet to the target transport layer proxy network element; based on receiving fourth indication information, stopping sending data to the first application server, wherein the fourth indication information is sent when the first application server is to start performing application context migration between the first application server and the second application server. ### Claim 12 (depends on 10) The communication apparatus according to claim 10, wherein when the program or the instructions is/are executed by the processor, the apparatus is enabled to perform the operations further comprising: sending the first context to the session management network element. ### Claim 13 A packet transmission method, comprising: based on a source transport layer proxy network element receiving third indication information, stopping performing, by the source transport layer proxy network element, transport layer processing on a packet on a first path based on a first context of the source transport layer proxy network element, wherein the first context is a context about packet transmission of the source transport layer proxy network element on the first path; establishing, by a target transport layer proxy network element, a fourth transport layer connection based on the first context; and based on the target transport layer proxy network element receiving first indication information, and the first indication information being used to indicate that application context migration between a first application server and a second application server is completed, performing, by the target transport layer proxy network element, transport layer processing on a packet on a second path based on a second context of the target transport layer proxy network element, and transmitting, on the second path, a packet obtained through the transport layer processing, wherein the second path comprises a third transport layer connection and the fourth transport layer connection; the second context is determined based on the first context and a context of the fourth transport layer connection; when the application context migration is being performed, packet transmission between the first application server and a transport layer proxy network element is stopped; and the transport layer proxy network element comprises the source transport layer proxy network element or the target transport layer proxy network element, wherein the first path is a path established between a terminal device and the first application server, the first path comprises a first transport layer connection and a second transport layer connection, the first transport layer connection is a transport layer connection between the source transport layer proxy network element and the terminal device, the second transport layer connection is a transport layer connection between the source transport layer proxy network element and the first application server, the third transport layer connection is a transport layer connection between the target transport layer proxy network element and the terminal device, and the fourth transport layer connection is a transport layer connection between the target transport layer proxy network element and the second application server. ### Claim 14 (depends on 13) The method according to claim 13, wherein the method further comprises: sending, by the source transport layer proxy network element, a first uplink transmission control protocol (TCP) packet and a first downlink multipath transmission control protocol (MPTCP) packet to the target transport layer proxy network element for transport layer processing, wherein the first uplink TCP packet is a packet that is received by the source transport layer proxy network element but that is not sent to the first application server, and the first downlink MPTCP packet is a packet that is received by the source transport layer proxy network element but that is not sent to the terminal device; encapsulating, by the target transport layer proxy network element, the first uplink TCP packet into a first uplink MPTCP packet based on the second context, and sending the first uplink MPTCP packet to the second application server through the fourth transport layer connection; and encapsulating, by the target transport layer proxy network element, the first downlink MPTCP packet into a first downlink TCP packet based on the second context of the target transport layer proxy network element, and sending the first downlink TCP packet to the terminal device through the third transport layer connection. ### Claim 15 (depends on 13) The method according to claim 13, wherein the first context comprises a first transport layer connection parameter and a second transport layer connection parameter, and the first transport layer connection parameter and the second transport layer connection parameter are used to perform transport layer processing; or the first context comprises a first transport layer connection parameter, a first transmission state parameter, a second transport layer connection parameter, and a second transmission state parameter, the first transport layer connection parameter and the second transport layer connection parameter are used to perform transport layer processing, the first transmission state parameter is used to indicate a packet transmission state of the first transport layer connection, and the second transmission state parameter is used to indicate a packet transmission state of the second transport layer connection. ### Claim 16 A communication system, wherein the communication system comprises a source transport layer proxy network device and a target transport layer proxy network device, wherein the source transport layer proxy network device is a hardware device including a processor and the target transport layer proxy network device is a hardware device including a processor, wherein the source transport layer proxy network device is configured to: based on receiving third indication information, stop performing transport layer processing on a packet on a first path based on a first context of the source transport layer proxy network device, wherein the first context is a context about packet transmission of the source transport layer proxy network device on the first path; and the target transport layer proxy network device is configured to: establish a fourth transport layer connection based on the first context; based on first indication information being received, and the first indication information being used to indicate that application context migration between a first application server and a second application server is completed, perform transport layer processing on a packet on a second path based on a second context of the target transport layer proxy network device; and transmit, on the second path, a packet obtained through the transport layer processing, wherein the second path comprises a third transport layer connection and the fourth transport layer connection; the second context is determined based on the first context and the fourth transport layer connection; when the application context migration is being performed, packet transmission between the first application server and a transport layer proxy network device is stopped; and the transport layer proxy network device comprises the source transport layer proxy network device or the target transport layer proxy network device, wherein the first path is a path established between a terminal device and the first application server, the first path comprises a first transport layer connection and a second transport layer connection, the first transport layer connection is a transport layer connection between the source transport layer proxy network device and the terminal device, the second transport layer connection is a transport layer connection between the source transport layer proxy network device and the first application server, the third transport layer connection is a transport layer connection between the target transport layer proxy network device and the terminal device, and the fourth transport layer connection is a transport layer connection between the target transport layer proxy network device and the second application server. ### Claim 17 (depends on 16) The system according to claim 16, wherein the source transport layer proxy network device is further configured to: send a first uplink transmission control protocol (TCP) packet and a first downlink multipath transmission control protocol (MPTCP) packet to the target transport layer proxy network device for transport layer processing, wherein the first uplink TCP packet is a packet that is received by the source transport layer proxy network device but that is not sent to the first application server, and the first downlink MPTCP packet is a packet that is received by the source transport layer proxy network device but that is not sent to the terminal device; and wherein the target transport layer proxy network device is further configured to: encapsulate the first uplink TCP packet into a first uplink MPTCP packet based on the second context, and sending the first uplink MPTCP packet to the second application server through the fourth transport layer connection; and encapsulate the first downlink MPTCP packet into a first downlink TCP packet based on the second context of the target transport layer proxy network device, and sending the first downlink TCP packet to the terminal device through the third transport layer connection. ### Claim 18 (depends on 16) The system according to claim 16, wherein the first context comprises a first transport layer connection parameter and a second transport layer connection parameter, and the first transport layer connection parameter and the second transport layer connection parameter are used to perform transport layer processing; or the first context comprises a first transport layer connection parameter, a first transmission state parameter, a second transport layer connection parameter, and a second transmission state parameter, the first transport layer connection parameter and the second transport layer connection parameter are used to perform transport layer processing, the first transmission state parameter is used to indicate a packet transmission state of the first transport layer connection, and the second transmission state parameter is used to indicate a packet transmission state of the second transport layer connection. ### Claim 19 (depends on 16) The system according to claim 16, wherein the system further comprises the first application server and the second application server, wherein the first application server is configured to: perform application context migration between the first application server and the second application server based on receiving an application migration instruction, wherein the application migration instruction is triggered when it is determined that the source transport layer proxy network device has stopped performing transport layer processing on a packet and that the target transport layer proxy network device has started performing transport layer processing on a packet. ### Claim 20 (depends on 16) The system according to claim 16, wherein the system further comprises a session management network device, wherein the session management network device is configured to: receive the first context from the source transport layer proxy network device, and send the first context to the target transport layer proxy network device.