Communications method, apparatus, and system

1. A communications method, the method comprising:

determining, by a session management network element, information about a target data plane instance, wherein the information about the target data plane instance comprises a routing indicator, wherein the routing indicator is used to determine an address of the target data plane instance, and wherein the target data plane instance is associated with a wireless integrated access and backhaul (IAB) node; and

sending, by the session management network element, an N4 session management request message and a first indication to the IAB node by using a mobility management network element or a donor node that provides a service for the IAB node, wherein the first indication is used to indicate the IAB node to send the N4 session management request message to the target data plane instance.

2. The method according to claim 1 , wherein before the sending, by the session management network element, the N4 session management request message and the first indication to the IAB node by using the mobility management network element, the method further comprises:

obtaining, by the session management network element, a local context of the IAB node; and

wherein the sending, by the session management network element, the N4 session management request message and the first indication to the IAB node by using the mobility management network element comprises:

generating, by the session management network element, a session management non-access stratum (NAS) message based on the context of the IAB node, wherein the session management NAS message comprises the N4 session management request message and the first indication; and

sending, by the session management network element, the session management NAS message to the IAB node by using the mobility management network element.

3. The method according to claim 1 , wherein the session management network element does not locally have the context of the IAB node, and the method further comprises:

sending, by the session management network element, the routing indicator to the mobility management network element, wherein after the mobility management network element is configured to determine, based on the routing indicator, that the mobility management network element locally has the context of the IAB node, the mobility management network element generates a mobility management NAS message based on the context of the IAB node, and sends the mobility management NAS message to the IAB node, and wherein the mobility management NAS message comprises the N4 session management request message and the first indication.

4. The method according to claim 3 , wherein before the sending, by the session management network element, the routing indicator to the mobility management network element, the method further comprises:

obtaining, by the session management network element, information about the mobility management network element of the IAB node from a subscriber data management network element.

5. The method according to claim 1 , wherein the sending, by the session management network element, the N4 session management request message and the first indication to the IAB node by using the donor node, the method further comprises:

sending, by the session management network element, the routing indicator to the donor node, wherein the donor node is configured to send a first message to the IAB node based on the routing indicator, and wherein the first message comprises the N4 session management request message and the first indication.

6. A communications apparatus, comprising:

a processor, configured to determine information about a target data plane instance, wherein the information about the target data plane instance comprises a routing indicator, wherein the routing indicator is used to determine an address of the target data plane instance, and wherein the target data plane instance is associated with a wireless integrated access and backhaul (IAB) node; and

a transceiver configured to send an N4 session management request message and a first indication to the IAB node by using a mobility management network element or a donor node that provides a service for the IAB node, wherein the first indication is used to indicate the IAB node to send the N4 session management request message to the target data plane instance.

7. The apparatus according to claim 6 , wherein before the transceiver is configured to send the N4 session management request message and the first indication to the IAB node by using the mobility management network element;

the processor is further configured to obtain a context that is of the IAB node and that is in the apparatus;

the processor is further configured to generate a session management non-access stratum NAS message based on the context of the IAB node, wherein the session management NAS message comprises the N4 session management request message and the first indication; and

the transceiver is further configured to send the session management NAS message to the IAB node by using the mobility management network element.

8. The apparatus according to claim 6 , wherein:

the transceiver is further configured to send the routing indicator to the mobility management network element, wherein after the mobility management network element is configured to determine, based on the routing indicator, that the mobility management network element locally has the context of the IAB node, the mobility management network element generates a mobility management NAS message based on the context of the IAB node, and sends the mobility management NAS message to the IAB node, and wherein the mobility management NAS message comprises the N4 session management request message and the first indication.

9. The apparatus according to claim 8 , wherein before the transceiver is configured to send the routing indicator to the mobility management network element;

the transceiver is further configured to obtain information about the mobility management network element of the IAB node from a subscriber data management network element.

10. The apparatus according to claim 6 , wherein that the transceiver is configured to send the N4 session management request message and the first indication to the IAB node by using the donor node further comprises:

sending the routing indicator to the donor node, wherein the donor node is configured to send a first message to the IAB node based on the routing indicator, and the first message comprises the N4 session management request message and the first indication.

11. A communications apparatus, comprising:

a processor configured to process information; and

a transceiver configured to:

receive an N4 session management request message and a first indication from a session management network element, wherein the first indication is used to indicate the transceiver to send the N4 session management request message to a target data plane instance; and

send the N4 session management request message to the target data plane instance according to the first indication, wherein the N4 session management request message is used to indicate to manage a session context of the target data plane instance.

12. The apparatus according to claim 11 , wherein:

the transceiver is further configured to receive the N4 session management response message sent by from the target data plane instance; and

the transceiver is further configured to send a second indication and the N4 session management response message to a donor node or a mobility management network element, wherein the second indication is used to indicate to send the N4 session management response message to the session management network element.

13. The apparatus according to claim 11 , wherein:

the transceiver is further configured to send a first message to a first device, wherein the first message comprises information about one or more data plane instances corresponding to a data plane module, the information about the one or more data plane instances comprises information about the target data plane instance, information about any data plane instance comprises a routing indicator, and wherein the first message is used to indicate the first device to register the information about the one or more data plane instances with the session management network element or a network storage network element, and wherein the routing indicator is used by the session management network element to determine an address of the any data plane instance, the any data plane instance is associated with the apparatus, and the first device comprises any one of the following: a network management network element, the donor node, or the mobility management network element.

14. The apparatus according to claim 13 , wherein the first message comprises a payload container, the payload container comprises the information about the one or more data plane instances, and a type of the payload container is used to indicate the first device to register the information about the one or more data plane instances with the session management network element or the network storage network element.

15. The apparatus according to claim 13 , wherein the first message further comprises a registration indication, and the registration indication is used to indicate the first device to register the information about the one or more data plane instances with the session management network element or the network storage network element.

16. The apparatus according to claim 13 ,

wherein there is a predefined operation interface between the apparatus and the first device, and the predefined operation interface is used to indicate to the first device to register the information about the one or more data plane instances with the session management network element or the network storage network element; and

wherein the transceiver is configured to send the first message to the first device through the predefined operation interface.

17. The apparatus according to claim 11 , wherein:

the information about the one or more data plane instances is transparently transmitted on the donor node or the mobility management network element; or

the information about the one or more data plane instances is processed by the donor node or the mobility management network element and then sent to the session management network element or the network storage network element.

18. A communications apparatus, comprising:

a processor configured to process information; and

a transceiver configured to;

receive an N4 session management request message and a first indication from a session management network element, wherein the first indication is used to indicate an integrated access and backhaul (IAB) node to send the N4 session management request message to a target data plane instance; and

send the N4 session management request message and the first indication to the IAB node.

19. The apparatus according to claim 18 ,

wherein before the transceiver is further configured to send the N4 session management request message and the first indication to the IAB node, the transceiver is further configured to receive a routing indicator from the session management network element, wherein the routing indicator is used to determine an address of the target data plane instance, and the target data plane instance is associated with the AB node;

wherein the processor is further configured to: after determining, based on the routing indicator, that the apparatus locally has a context of the IAB node, generate a mobility management non-access stratum (NAS) message based on the context of the IAB node; and

wherein the transceiver is further configured to send the mobility management NAS message to the IAB node, wherein the mobility management NAS message comprises the N4 session management request message and the first indication.

20. The apparatus according to claim 18 , wherein:

the transceiver is further configured to receive a first message, wherein the first message comprises information about one or more data plane instances of a data plane module, the first message is used to indicate the apparatus to register the information about the one or more data plane instances with the session management network element or a Network Function Repository (NRF) network element, information about any data plane instance comprises the routing indicator, and the information about the one or more data plane instances comprises information about the target data plane instance; and

the processor is further configured to register the information about the one or more data plane instances with the session management network element or the network storage network element based on the first message by using the transceiver.