Network architecture and information exchange method and apparatus

1. An information exchange method, comprising:

establishing a link setup between a centralized unit-control plane (CU-CP) and a centralized unit-user plane (CU-UP) by at least one of

obtaining, by the CU-CP, an address of the CU-UP by using a domain name system or an operation and maintenance system configuration, sending, by the CU-CP, a first link setup request to the CU-UP using the address of the CU-UP, wherein the first link setup request carries at least one of an identifier of the CU-CP or a name of the CU-CP, and receiving, by the CU-CP, a first link setup response returned by the CU-UP, wherein the first link setup response carries at least one of an identifier of the CU-UP or a name of the CU-UP; or

receiving, by the CU-CP, a second link setup request sent by the CU-UP based on an address of the CU-CP, wherein the second link setup request carries at least one of the identifier of the CU-UP or the name of the CU-UP, and returning, by the CU-CP, a second link setup response to the CU-UP based on the second link setup request, wherein the second link setup response carries at least one of the identifier of the CU-CP or the name of the CU-CP.

2. The method according to claim 1 , further comprising:

obtaining, by the CU-UP, the address of the CU-CP by using the domain name system or the operation and maintenance system configuration.

3. The method according to claim 1 , further comprising:

after establishing the link setup between the CU-CP and the CU-UP, in response to determining that an attach procedure initiated by first user equipment (UE) is detected, sending, by the CU-CP, a data bearer (DRB) setup request to the CU-UP, wherein the DRB setup request carries a to-be-configured evolved radio access bearer (E-RAB) setup list, and each entry in the to-be-configured E-RAB setup list comprises an E-RAB identifier, an internet protocol (IP) address of a core network user plane function (UPF), and a tunnel identifier of the UPF, wherein the CU-UP sets up an uplink user plane tunnel between the CU-UP and the UPF based on the to-be-configured E-RAB setup list;

receiving, by the CU-CP, a DRB setup response returned by the CU-UP, wherein the DRB setup response comprises an E-RAB setup list and a to-be-configured radio bearer (RB) setup list, each entry in the E-RAB setup list comprises an E-RAB identifier, an IP address of the CU-UP, and a tunnel identifier of the CU-UP, and each entry in the to-be-configured RB setup list comprises an RB identifier, the IP address of the CU-UP, and the tunnel identifier of the CU-UP;

sending, by the CU-CP, the to-be-configured RB setup list to a distributed control unit (DU), wherein the DU sets up an uplink user plane tunnel to the CU-UP using the to-be-configured RB setup list;

sending, by the CU-CP, an RB setup list to the CU-UP, wherein each entry in the RB setup list comprises an RB identifier, an IP address of the DU, and a tunnel identifier of the DU, wherein the CU-UP sets up a downlink user plane tunnel to the DU based on the RB setup list; and

sending, by the CU-CP, the E-RAB setup list to the UPF, wherein the CU-UP sets up a downlink user plane tunnel to the UPF.

4. The method according to claim 3 , wherein the data bearer (DRB) setup request comprises security context information and a flow-level quality of service (QoS) list,

wherein the security context information comprises an encryption algorithm, an integrity protection algorithm, and a security key, and wherein the CU-UP is configured to derive, based on the security context information, a user plane encryption protection key and an integrity protection key, and

wherein each entry in the flow-level QoS list comprises a radio access bearer (RAB) identifier and corresponding flow-level QoS, and wherein the CU-UP is configured to be notified of an RAB to be set up and corresponding QoS information according to the flow level QoS list.

5. The method according to claim 3 , wherein the sending, by the CU-CP, the RB setup list to the CU-UP comprises:

sending, by the CU-CP, a DRB modification request to the CU-UP, wherein the DRB modification request carries the RB setup list.

6. The method according to claim 3 , wherein each entry in the to-be-configured RB setup list further comprises a packet data convergence protocol (PDCP) configuration of each RB.

7. The method according to claim 6 , wherein sending, by the CU-CP, the to-be-configured RB setup list to the DU comprises:

sending, by the CU-CP, an RB bearer setup request to the DU, wherein the RB bearer setup request carries the to-be-configured RB setup list.

8. The method according to claim 3 , further comprising:

receiving, by the CU-CP, a DRB setup indication sent by the CU-UP, wherein the DRB setup indication indicates that a current RB resource cannot carry a data flow received by the CU-UP, and

in response to receiving the DRB setup indication, performing, by the CU-CP, one of:

creating, by the CU-CP, a new RB resource as a first target RB to carry the data flow; or

invoking, by the CU-CP, an existing RB resource as the first target RB to carry the data flow.

9. The method according to claim 8 , wherein creating, by the CU-CP, the new RB resource as the first target RB comprises:

sending, by the CU-CP, a DRB setup request to the CU-UP, wherein the DRB setup request comprises an identifier of the first target RB and data flow level QoS corresponding to the first target RB;

receiving, by the CU-CP, a DRB setup response returned by the CU-UP, wherein the DRB setup response comprises the identifier of the first target RB, the IP address of the CU-UP, and the tunnel identifier of the CU-UP;

sending, by the CU-CP, the identifier of the first target RB, the IP address of the CU-UP, and the tunnel identifier of the CU-UP to the DU, wherein the DU sets up an uplink user plane tunnel for the first target RB to the CU-UP; and

sending, by the CU-CP, the identifier of the first target RB, the IP address of the DU, and the tunnel identifier of the DU to the CU-UP, wherein the CU-UP sets up a downlink user plane tunnel to the DU.

10. An information exchange apparatus, comprising:

at least one processor; and

a non-transitory computer-readable storage medium coupled to the at least one processor and storing programming instructions for execution by the at least one processor, wherein the programming instructions instruct the at least one processor to perform one or more operations comprising:

establishing a link setup between a centralized unit-control plane (CU-CP) and a centralized unit-user plane (CU-UP) by at least one of

obtaining an address of the CU-UP using a domain name system or an operation and maintenance system configuration, sending a first link setup request to the CU-UP using the address of the CU-UP, wherein the first link setup request carries at least one of an identifier of the CU-CP or a name of the CU-CP, and receiving a first link setup response returned by the CU-UP, wherein the first link setup response carries at least one of an identifier of the CU-UP or a name of the CU-UP; or

receiving a second link setup request sent by the CU-UP based on an address of the CU-CP, wherein the second link setup request carries at least one of the identifier of the CU-UP or the name of the CU-UP, and returning a second link setup response to the CU-UP based on the second link setup request, wherein the second link setup response carries at least one of the identifier of the CU-CP or the name of the CU-CP.

11. The information exchange apparatus according to claim 10 , wherein the operations further comprise:

in response to determining that an attach procedure initiated by first user equipment (UE) is detected, sending a data bearer (DRB) setup request to the CU-UP, wherein the DRB setup request carries a to-be-configured evolved radio access bearer (E-RAB) setup list, and each entry in the to-be-configured E-RAB setup list comprises an E-RAB identifier, an internet protocol (IP) address of a core network user plane function (UPF), and a tunnel identifier of the UPF, wherein the CU-UP sets up an uplink user plane tunnel between the CU-UP and the UPF based on the to-be-configured E-RAB setup list;

receiving a DRB setup response returned by the CU-UP, wherein the DRB setup response comprises an E-RAB setup list and a to-be-configured radio bearer (RB) setup list, each entry in the E-RAB setup list comprises an E-RAB identifier, an IP address of the CU-UP, and a tunnel identifier of the CU-UP, and each entry in the to-be-configured RB setup list comprises an RB identifier, the IP address of the CU-UP, and the tunnel identifier of the CU-UP;

sending the to-be-configured RB setup list to a DU, wherein the DU sets up an uplink user plane tunnel to the CU-UP by using the to-be-configured RB setup list;

sending an RB setup list to the CU-UP, wherein each entry in the RB setup list comprises an RB identifier, an IP address of the DU, and a tunnel identifier of the DU, wherein the CU-UP sets up a downlink user plane tunnel to the DU based on the RB setup list; and

sending the E-RAB setup list to the UPF, wherein the CU-UP sets up a downlink user plane tunnel to the UPF.

12. The information exchange apparatus according to claim 11 , wherein the data bearer (DRB) setup request comprises security context information and a flow-level quality of service (QoS) list,

wherein the security context information comprises an encryption algorithm, an integrity protection algorithm, and a security key, and the CU-UP is configured to derive, based on the security context information, a user plane encryption protection key and an integrity protection key, and

wherein each entry in the flow-level QoS list comprises an RAB identifier and corresponding flow-level QoS, and wherein the CU-UP is configured to be notified of an RAB to be set up and corresponding QoS information according to the flow-level QoS list.

13. The information exchange apparatus according to claim 11 , wherein the operations further comprise: sending a DRB modification request to the CU-UP, wherein the DRB modification request carries the RB setup list.

14. The information exchange apparatus according to claim 13 , wherein the operations further comprise:

sending an RB bearer setup request to the DU, wherein the RB bearer setup request carries the to-be-configured RB setup list.

15. The information exchange apparatus according to claim 11 , wherein the operations further comprise:

receiving a DRB setup indication sent by the CU-UP, wherein the DRB setup indication indicates that a current RB resource cannot carry a data flow received by the CU-UP; and

in response to receiving the DRB setup indication, performing one of:

creating a new RB resource as a first target RB to carry the data flow; or

invoking an existing RB resource as the first target RB to carry the data flow.

16. The information exchange apparatus according to claim 15 , wherein creating the new RB resource as the first target RB to carry the data flow comprises:

sending a DRB setup request to the CU-UP, wherein the DRB setup request comprises an identifier of the first target RB and data flow level QoS corresponding to the first target RB;

receiving a DRB setup response returned by the CU-UP, wherein the DRB setup response comprises the identifier of the first target RB, the IP address of the CU-UP, and the tunnel identifier of the CU-UP;

sending the identifier of the first target RB, the IP address of the CU-UP, and the tunnel identifier of the CU-UP to the DU, wherein the DU sets up an uplink user plane tunnel for the first target RB to the CU-UP; and

sending the identifier of the first target RB, the IP address of the DU, and the tunnel identifier of the DU to the CU-UP, wherein the CU-UP sets up a downlink user plane tunnel to the DU.

17. The information exchange apparatus according to claim 15 , wherein invoking the existing RB resource as the first target RB to carry the data flow comprises:

sending an RB modification request to the DU, wherein the RB modification request indicates that the RB is used to carry the data flow; and

receiving an RB modification response returned by the DU.

18. The information exchange apparatus according to claim 10 , wherein the CU-UP is configured to obtain the address of the CU-CP by using the domain name system or the operation and maintenance system configuration.

19. A non-transitory computer-readable storage medium coupled to at least one processor and storing programming instructions for execution by the at least one processor, wherein the programming instructions instruct the at least one processor to perform one or more operations comprising:

establishing a link setup between a centralized unit-control plane (CU-CP) and a centralized unit-user plane (CU-UP) by at least one of

obtaining an address of the CU-UP by using a domain name system or an operation and maintenance system configuration, sending a first link setup request to the CU-UP using the address of the CU-UP, wherein the first link setup request carries at least one of an identifier of the CU-CP or a name of the CU-CP, and receiving a first link setup response returned by the CU-UP, wherein the first link setup response carries at least one of an identifier of the CU-UP or a name of the CU-UP; or

receiving a second link setup request sent by the CU-UP based on an address of the CU-CP, wherein the second link setup request carries at least one of the identifier of the CU-UP or the name of the CU-UP, and returning a second link setup response to the CU-UP based on the second link setup request, wherein the second link setup response carries at least one of the identifier of the CU-CP or the name of the CU-CP.

20. The non-transitory computer-readable storage medium according to claim 19 , wherein the operations further comprise:

in response to determining that an attach procedure initiated by first user equipment (UE) is detected, sending a data bearer (DRB) setup request to the CU-UP, wherein the DRB setup request carries a to-be-configured evolved radio access bearer (E-RAB) setup list, and each entry in the to-be-configured E-RAB setup list comprises an E-RAB identifier, an internet protocol (IP) address of a core network user plane function (UPF), and a tunnel identifier of the UPF, wherein the CU-UP sets up an uplink user plane tunnel between the CU-UP and the UPF based on the to-be-configured E-RAB setup list;

receiving a DRB setup response returned by the CU-UP, wherein the DRB setup response comprises an E-RAB setup list and a to-be-configured radio bearer (RB) setup list, each entry in the E-RAB setup list comprises an E-RAB identifier, an IP address of the CU-UP, and a tunnel identifier of the CU-UP, and each entry in the to-be-configured RB setup list comprises an RB identifier, the IP address of the CU-UP, and the tunnel identifier of the CU-UP;

sending the to-be-configured RB setup list to a DU, wherein the DU sets up an uplink user plane tunnel to the CU-UP by using the to-be-configured RB setup list;

sending an RB setup list to the CU-UP, wherein each entry in the RB setup list comprises an RB identifier, an IP address of the DU, and a tunnel identifier of the DU, wherein the CU-UP sets up a downlink user plane tunnel to the DU based on the RB setup list; and

sending the E-RAB setup list to the UPF, wherein the CU-UP sets up a downlink user plane tunnel to the UPF.