Communication method and apparatus

1. A communication method, comprising:

receiving, by a first session management network element, a protocol data unit (PDU) session modification request, wherein the PDU session modification request comprises first identification information of multicast data and identification information of a first PDU session, and the first session management network element is configured to manage a user plane network element corresponding to the first PDU session;

obtaining, by the first session management network element, quality of service (QoS) context information of the multicast data based on the first identification information of the multicast data; and

sending, by the first session management network element to an access network device, QoS context information of unicast data and identification information of a multicast group corresponding to the multicast data, wherein the identification information of the multicast group corresponding to the multicast data is usable by the access network device for determining the QoS context information of the multicast data;

wherein obtaining the QoS context information of the multicast data based on the first identification information of the multicast data comprises:

obtaining, by the first session management network element, identification information of a second session management network element based on the first identification information of the multicast data, wherein the second session management network element manages a multicast user plane network element, and the multicast user plane network element is an anchor for transmitting the multicast data;

sending, by the first session management network element, second identification information of the multicast data to the second session management network element based on the identification information of the second session management network element; and

receiving, by the first session management network element, the QoS context information of the multicast data from the second session management network element.

2. The method according to claim 1 , wherein the first identification information comprises:

an identifier of the multicast group corresponding to the multicast data; or

an IP address of an application server that provides the multicast data.

3. The method according to claim 1 , wherein the first identification information comprises an identifier (ID) of a multicast PDU session for transmitting the multicast data.

4. The method according to claim 1 , wherein the QoS context information of the multicast data comprises one or more of the following:

identification information of a multicast QoS flow;

identification information of a multicast context;

a QoS parameter corresponding to the multicast QoS flow; or

tunnel information corresponding to the multicast data.

5. The method according to claim 1 , wherein the QoS context information of the unicast data comprises one or more of the following:

identification information of a unicast QoS flow;

identification information of a unicast context;

a QoS parameter corresponding to the unicast QoS flow; or

tunnel information corresponding to the unicast data.

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

generating, by the first session management network element, the QoS context information of the unicast data based on the QoS context information of the multicast data.

7. The method according to claim 6 , wherein the QoS context information of the unicast data corresponds to the QoS context information of the multicast data.

8. The method according to claim 1 , wherein the second identification information comprises:

an identifier of the multicast group corresponding to the multicast data; or

an IP address of an application server that provides the multicast data.

9. A communication apparatus, comprising:

at least one processor; and

a non-transitory storage medium storing executable instructions, wherein the non-transitory storage medium is coupled to the at least one processor;

wherein the executable instructions, when executed by the at least one processor, facilitate performance of the following by the communication apparatus:

receiving a protocol data unit (PDU) session modification request, wherein the PDU session modification request comprises first identification information of multicast data and identification information of a first PDU session, and the communication apparatus is configured to manage a user plane network element corresponding to the first PDU session;

obtaining quality of service (QoS) context information of the multicast data based on the first identification information of the multicast data; and

sending, to an access network device, QoS context information of unicast data and identification information of a multicast group corresponding to the multicast data, wherein the identification information of the multicast group corresponding to the multicast data is usable by the access network device for determining the QoS context information of the multicast data;

wherein obtaining the QoS context information of the multicast data based on the first identification information of the multicast data comprises:

obtaining identification information of a second session management network element based on the first identification information of the multicast data, wherein the second session management network element manages a multicast user plane network element, and the multicast user plane network element is an anchor for transmitting the multicast data;

sending second identification information of the multicast data to the second session management network element based on the identification information of the second session management network element; and

receiving the QoS context information of the multicast data from the second session management network element.

10. The apparatus according to claim 9 , wherein the first identification information comprises:

an identifier of the multicast group corresponding to the multicast data; or

an IP address of an application server that provides the multicast data.

11. The apparatus according to claim 9 , wherein the first identification information comprises an identifier (ID) of a multicast PDU session used to transmit the multicast data.

12. The apparatus according to claim 9 , wherein the QoS context information of the multicast data comprises one or more of the following:

identification information of a multicast QoS flow;

identification information of a multicast context;

a QoS parameter corresponding to the multicast QoS flow; or

tunnel information corresponding to the multicast data.

13. The apparatus according to claim 9 , wherein the QoS context information of the unicast data comprises one or more of the following:

identification information of a unicast QoS flow;

identification information of a unicast context;

a QoS parameter corresponding to the unicast QoS flow; or

tunnel information corresponding to the unicast data.

14. The apparatus according to claim 9 , wherein the at least one processor is further configured to:

generate the QoS context information of the unicast data based on the QoS context information of the multicast data.

15. A communication system, comprising:

a first session management network element; and

a user plane network element;

wherein the first session management network element is configured to:

receive a protocol data unit (PDU) session modification request, wherein the PDU session modification request comprises first identification information of multicast data and identification information of a first PDU session, and the first session management network element is configured to manage the user plane network element;

obtain quality of service (QoS) context information of the multicast data based on the first identification information of the multicast data; and

send, to an access network device, QoS context information of unicast data and identification information of a multicast group corresponding to the multicast data, wherein the identification information of the multicast group corresponding to the multicast data is usable by the access network device for determining the QoS context information of the multicast data; and

wherein the user plane network element corresponds to the first PDU session;

wherein obtaining the QoS context information of the multicast data based on the first identification information of the multicast data comprises:

obtaining identification information of a second session management network element based on the first identification information of the multicast data, wherein the second session management network element is configured to manage a multicast user plane network element, and the multicast user plane network element is an anchor for transmitting the multicast data;

sending second identification information of the multicast data to the session management network element based on the identification information of the second session management network element; and

receiving the QoS context information of the multicast data from the second session management network element.

16. The system according to claim 15 , wherein the system further comprises the second session management network element;

wherein the second session management network element is further configured to:

receive the second identification information of the multicast data from the first session management network element; and

send the QoS context information of the multicast data to the first session management network element.

17. A non-transitory computer-readable medium having processor-executable instructions stored thereon for a communication method for a first session management network, wherein the processor-executable instructions, when executed, facilitate performance of the following:

receiving a protocol data unit (PDU) session modification request, wherein the PDU session modification request comprises first identification information of multicast data and identification information of a first PDU session, and the first session management network element is configured to manage a user plane network element corresponding to the first PDU session;

obtaining quality of service (QoS) context information of the multicast data based on the first identification information of the multicast data; and

sending, to an access network device, QoS context information of unicast data and identification information of a multicast group corresponding to the multicast data, wherein the identification information of the multicast group corresponding to the multicast data is usable by the access network device for determining the QoS context information of the multicast data;

wherein obtaining the QoS context information of the multicast data based on the first identification information of the multicast data comprises:

obtaining identification information of a second session management network element based on the first identification information of the multicast data, wherein the second session management network element is configured to manage a multicast user plane network element, and the multicast user plane network element is an anchor for transmitting the multicast data;

sending second identification information of the multicast data to the second session management network element based on the identification information of the second session management network element; and

receiving the QoS context information of the multicast data from the second session management network element.

18. The non-transitory computer-readable medium according to claim 17 , wherein the first identification information comprises:

an identifier of the multicast group corresponding to the multicast data; or

an IP address of an application server that provides the multicast data.

19. The non-transitory computer-readable medium according to claim 17 , wherein the processor-executable instructions, when executed, further facilitate performance of the following:

generating the QoS context information of the unicast data based on the QoS context information of the multicast data.