Communication method and communication apparatus

A method comprising:

• obtaining, by a user plane function network element, first indication information, wherein the first indication information indicates that a first service flow is associated with a second service flow;
• receiving, by the user plane function network element, a first protocol data unit set PDU set of the first service flow and a second PDU set of the second service flow, wherein the first PDU set carries third association information, the second PDU set carries fourth association information, and the third association information and the fourth association information are used by the user plane function network element to determine that the first PDU set is associated with the second PDU set;
• adding, by the user plane function network element, association information to the first PDU set and/or the second PDU set based on the first indication information, the third association information, and the fourth association information, wherein the association information is used by an access network device to determine that the first PDU set is associated with the second PDU set;
• and
• sending, by the user plane function network element, the first PDU set and the second PDU set to the access network device.

A communication apparatus, comprising a processor and an interface circuit, wherein the interface circuit is configured to receive a signal from a communication apparatus other than the communication apparatus and transmit the signal to the processor or send a signal from the processor to a communication apparatus other than the communication apparatus, and the processor is configured to implement:

• obtaining first indication information, wherein the first indication information indicates that a first service flow is associated with a second service flow;
• receiving a first protocol data unit set PDU set of the first service flow and a second PDU set of the second service flow, wherein the first PDU set and/or the second PDU set carry/carries association information, and the association information is used by the access network device to determine that the first PDU set is associated with the second PDU set;
• and
• performing synchronous transmission on the first PDU set and the second PDU set based on the first indication information and the association information.