Patent Publication Number: US-2019191019-A1

Title: Protocol layer distribution indication method and apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/CN2017/098282, filed on Aug. 21, 2017, which claims the priority to Chinese Patent Application No. 201610741693.9, filed on Aug. 26, 2016. The disclosures of the aforementioned applications are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     This application relates to wireless communications technologies, and in particular, to a protocol layer distribution indication method and apparatus. 
     BACKGROUND 
     A cloud radio access network (C-RAN) is a new type of radio access network architecture put forward based on an existing network condition and a trend in technical progress. Specifically, the C-RAN is a clean radio access network architecture based on centralized processing, collaborative radio, and a real-time cloud computing infrastructure. Essence of the C-RAN is to reduce a quantity of base station equipment rooms, reduce energy consumption, and use a cooperative virtualization technology to implement resource sharing and dynamic scheduling and improve spectral efficiency, so as to implement low-cost, high-bandwidth, and high-flexibility operation. In the C-RAN, a central unit (CU) is connected to a plurality of distributed units (DU), and each protocol layer entity may be distributed to the DU or the CU. 
     The 3rd Generation Partnership Project (3GPP) relates to more high-layer distribution. After the C-RAN is introduced to the 3GPP, there is still no proper protocol layer distribution method. 
     SUMMARY 
     This application provides a protocol layer distribution indication method and apparatus, to provide a dynamic and flexible protocol layer distribution method. 
     A first aspect of this application provides a protocol layer distribution indication method, including: 
     determining, by a CU, a protocol layer distribution manner between the CU and a DU; 
     generating, by the CU, first protocol layer distribution information based on the protocol layer distribution manner; and 
     sending, by the CU, the first protocol layer distribution information to the DU. 
     In this method, the first protocol layer distribution information may be used to indicate the protocol layer distribution manner. 
     In one embodiment, the sending, by the CU, the first protocol layer distribution information to the DU includes: 
     sending, by the CU, an interface setup request to the DU, where the interface setup request includes the first protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a mapping relationship between quality level information and protocol layer distribution information. The mapping relationship is used to instruct the DU to process data based on protocol layer distribution information corresponding to a quality level of received data. For example, if a protocol layer distribution manner corresponding to quality of service (QoS) class identifier or QCI=1 is “a MAC (media access control) layer and a protocol layer below the MAC layer are distributed to the DU”, when receiving data on a bearer corresponding to QCI=1, the DU enables protocol layer entities at the MAC layer and at the layer below the MAC layer to process the data. The mapping relationship between the quality level information and the protocol layer distribution information may also be described as a mapping relationship between a quality level and a protocol layer distribution manner. 
     In one embodiment, the first protocol layer distribution information includes a mapping relationship between slice information and protocol layer distribution information. The mapping relationship is used to instruct the DU to process data based on protocol layer distribution information corresponding to data slice information. For example, if a protocol layer distribution manner corresponding to a data slice  010  is “a packet data convergence protocol or PDCP layer and a protocol layer below the PDCP layer are distributed to the DU”, when receiving data of the data slice  010 , the DU enables protocol layer entities at the PDCP layer and at the layer below the PDCP layer to process the data. The mapping relationship between the slice information and the protocol layer distribution information may also be described as a mapping relationship between a slice and a protocol layer distribution manner. Slicing may be performed on a plurality of objects, such as slicing on data, slicing on a network, and slicing on time. 
     It can be learned from the foregoing two examples of the first protocol layer distribution information that the first protocol layer distribution information may include mapping relationships between different data attributes and protocol layer distribution manners according to different network requirements. For example, the first protocol layer distribution information may include a mapping relationship between a bearer and a protocol layer distribution manner, or a mapping relationship between a service type and a protocol layer distribution manner. 
     In one embodiment, the determining, by a CU, a protocol layer distribution manner between the CU and a DU includes: 
     determining, by the CU, the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the CU and a protocol layer distribution manner; or determining, by the CU, the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the DU and a protocol layer distribution manner. 
     In one embodiment, the sending, by the CU, the first protocol layer distribution information to the DU includes: 
     sending, by the CU, a DU addition request to the DU, where the DU addition request includes the first protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate a currently used protocol layer distribution manner to the DU. 
     In one embodiment, the DU addition request further includes information about a terminal to be served. 
     In one embodiment, the CU determines the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the terminal and protocol layer distribution information. 
     In one embodiment, the DU addition request further includes bearer information. 
     In one embodiment, the CU determines the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the bearer information and protocol layer distribution information. 
     In one embodiment, the DU addition request further includes slice information. 
     In one embodiment, the CU determines the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the slice information and protocol layer distribution information. 
     In one embodiment, the DU addition request further includes data flow information. 
     In one embodiment, the CU determines the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the data flow information and protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes uplink protocol layer distribution information and downlink protocol layer distribution information. 
     In one embodiment, the sending, by the CU, the first protocol layer distribution information to the DU includes: 
     sending, by the CU, a data packet to the DU, where the data packet includes the first protocol layer distribution information, and the first protocol layer distribution information includes downlink protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate, to the DU, a protocol layer distribution manner used by the current data packet. 
     In one embodiment, the method further includes: receiving, by the CU, a data packet sent by the DU, where the data packet includes second protocol layer distribution information, and the second protocol layer distribution information includes uplink protocol layer distribution information; and 
     the second protocol layer distribution information includes a second protocol layer distribution indication, and the second protocol layer distribution indication is used to indicate, to the CU, a protocol layer distribution manner used by the current data packet; 
     determining, by the CU, a to-be-enabled function at each protocol layer, and generating function indication information; and 
     sending, by the CU, the function indication information to the DU. 
     A second aspect of this application provides a protocol layer distribution indication method, including: 
     receiving, by a DU, first protocol layer distribution information sent by a CU; 
     determining, by the DU, a protocol layer distribution manner between the CU and the DU based on the first protocol layer distribution information; and 
     processing, by the DU, data based on the protocol layer distribution manner between the CU and the DU. 
     In one embodiment, the receiving, by a DU, first protocol layer distribution information sent by a CU includes: 
     receiving, by the DU, an interface setup request sent by the CU, where the interface setup request includes the first protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a mapping relationship between quality level information and protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a mapping relationship between slice information and protocol layer distribution information. 
     In one embodiment, the receiving, by a DU, first protocol layer distribution information sent by a CU includes: 
     receiving, by the DU, a DU addition request sent by the CU, where the DU addition request includes the first protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate a currently used protocol layer distribution manner to the DU. 
     In one embodiment, the first protocol layer distribution information further includes information about a terminal to be served. 
     In one embodiment, the first protocol layer distribution information includes bearer information. 
     In one embodiment, the first protocol layer distribution information further includes slice information. 
     In one embodiment, the first protocol layer distribution information further includes data flow information. 
     In one embodiment, the first protocol layer distribution information includes uplink protocol layer distribution information and downlink protocol layer distribution information. 
     In one embodiment, the receiving, by a DU, first protocol layer distribution information sent by a CU includes: 
     receiving, by the DU, a data packet sent by the CU, where the data packet includes the first protocol layer distribution information, and the first protocol layer distribution information includes downlink protocol layer distribution information. 
     In one embodiment, the DU sends a data packet to the CU, where the data packet includes second protocol layer distribution information, and the second protocol layer distribution information includes uplink protocol layer distribution information; and the second protocol layer distribution information includes a second protocol layer distribution indication, and the second protocol layer distribution indication is used to indicate, to the CU, a protocol layer distribution manner used by the data packet. 
     In one embodiment, the method further includes: 
     receiving, by the DU, function indication information sent by the CU, where the function indication information is used to indicate a to-be-enabled function at each protocol layer. 
     A third aspect of this application provides a protocol layer distribution indication method, including: 
     determining, by a DU, a protocol layer distribution manner between a CU and the DU; 
     generating, by the DU, second protocol layer distribution information based on the protocol layer distribution manner; and 
     sending, by the DU, the second protocol layer distribution information to the CU. 
     In one embodiment, the sending, by the DU, the second protocol layer distribution information to the CU includes: 
     sending, by the DU, an interface setup response to the CU, where the interface setup response includes the second protocol layer distribution information. 
     In one embodiment, the sending, by the DU, the second protocol layer distribution information to the CU includes: 
     sending, by the DU, a DU addition response to the CU, where the DU addition response includes the second protocol layer distribution information. 
     A fourth aspect of this application provides a protocol layer distribution indication apparatus, where the apparatus includes a module or a means (means) configured or used to perform the method according to the first aspect and the implementations of the first aspect. 
     A fifth aspect of this application provides a protocol layer distribution indication apparatus, where the apparatus includes a module or a means (means) configured or used to perform the method according to the second aspect and the implementations of the second aspect. 
     A sixth aspect of this application provides a protocol layer distribution indication apparatus, where the apparatus includes a module or a means (means) configured or used to perform the method according to the third aspect and the implementations of the third aspect. 
     A seventh aspect of this application provides a protocol layer distribution indication apparatus, where the apparatus includes a processor and a memory. The memory is configured to store a program, and the processor invokes the program stored in the memory, to perform the method according to the first aspect of this application. 
     An eighth aspect of this application provides a protocol layer distribution indication apparatus, where the apparatus includes a processor and a memory. The memory is configured to store a program, and the processor invokes the program stored in the memory, to perform the method according to the second aspect of this application. 
     A ninth aspect of this application provides a protocol layer distribution indication apparatus, where the apparatus includes a processor and a memory. The memory is configured to store a program, and the processor invokes the program stored in the memory, to perform the method according to the third aspect of this application. 
     A tenth aspect of this application provides a protocol layer distribution indication apparatus, including at least one processing element (or chip) configured to perform the method in the first aspect. 
     An eleventh aspect of this application provides a protocol layer distribution indication apparatus, including at least one processing element (or chip) configured to perform the method in the second aspect. 
     A twelfth aspect of this application provides a protocol layer distribution indication apparatus, including at least one processing element (or chip) configured to perform the method in the third aspect. 
     In this application, the CU determines the protocol layer distribution manner between the CU and the DU, further generates the first protocol layer distribution information based on the protocol layer distribution manner, and sends the first protocol layer distribution information to the DU, so that the protocol layer distribution manner can be dynamically determined, and dynamically notified to the DU. The DU may also change a protocol layer distribution in a timely manner based on the received first protocol layer distribution information. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic diagram of a network architecture of a protocol layer distribution indication method according to this application; 
         FIG. 2  is a schematic structural diagram of protocol layers; 
         FIG. 3  is a schematic flowchart of a protocol layer distribution indication method according to this application; 
         FIG. 4  is a schematic flowchart of another protocol layer distribution indication method according to this application; 
         FIG. 5  is a schematic flowchart of another protocol layer distribution indication method according to this application; 
         FIG. 6  is a schematic structural diagram of a protocol layer distribution indication apparatus according to this application; 
         FIG. 7  is a schematic structural diagram of another protocol layer distribution indication apparatus according to this application; 
         FIG. 8  is a schematic structural diagram of another protocol layer distribution indication apparatus according to this application; 
         FIG. 9  is a schematic structural diagram of another protocol layer distribution indication apparatus according to this application; and 
         FIG. 10  is a schematic structural diagram of another protocol layer distribution indication apparatus according to this application. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A base station, also referred to as a radio access network (RAN) device, is a device that connects a terminal to a radio network. The base station may be a base transceiver station (BTS) in a Global System for Mobile Communications (GSM) or Code Division Multiple Access (CDMA), or may be a NodeB (NB) in Wideband Code Division Multiple Access (WCDMA), or may be an evolved NodeB (eNodeB) in Long Term Evolution (LTE), a relay node or an access point, a base station in a future 5G network, or the like. No limitation is imposed herein. 
     A terminal may be a wireless terminal or a wired terminal. The wireless terminal may be a device that provides a user with voice and/or other service data connectivity, a handheld device with a wireless connection function, or another processing device connected to a wireless modem. The wireless terminal may communicate with one or more core networks by using a radio access network (Radio Access Network, RAN). The wireless terminal may be a mobile terminal such as a mobile phone (also referred to as a “cellular” phone) and a computer with a mobile terminal, for example, may be a portable, pocket-sized, handheld, computer built-in, or in-vehicle mobile apparatus that exchanges voice and/or data with the radio access network. For example, the wireless terminal may be a device such as a personal communications service (PCS) phone, a cordless telephone set, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, or a personal digital assistant (PDA). The wireless terminal may also be referred to as a system, a subscriber unit, a subscriber station, a mobile station, a mobile console, a remote station, a remote terminal, an access terminal, a user terminal, a user agent, or a user device (or User Equipment). No limitation is imposed herein. 
     “A plurality of” in this application means two or more than two. The term “and/or” describes an association relationship for describing associated objects and represents that three relationships may exist. For example, A and/or B may represent the following three cases: Only A exists, both A and B exist, and only B exists. The character “/” usually indicates an “or” relationship between the associated objects. 
       FIG. 1  is a schematic diagram of a network architecture of a protocol layer distribution indication method according to this application. This application may be applied to a C-RAN architecture, but is not limited thereto. As shown in  FIG. 1 , the network architecture includes a CU  01  and DUs  02 . One CU  01  is communicatively connected to a plurality of DUs  02 . Both the CU and the DUs may be integrated into a base station. This is not limited herein. 
       FIG. 2  is a schematic structural diagram of protocol layers. Eight protocol layers are used as an example in this embodiment. The eight protocol layers may include a radio resource control (RRC) layer, a Packet Data Convergence Protocol (PDCP) layer, a high-layer Radio Link Control layer (denoted as a high-RLC layer), a low-layer RLC layer (denoted as a low-RLC layer), a high-layer Media Access Control (MAC) layer (denoted as a high-MAC layer), a low-layer MAC layer (denoted as a low-MAC layer), a high-layer physical layer (PHY) (denoted as a high-PHY layer), and a low-layer PHY layer (denoted as a low-PHY layer). 
     As shown in  FIG. 2 , downlink transmission data is sequentially processed at the RRC layer to the low-PHY layer, and is finally sent by using a radio frequency (RF) antenna. After being received by using an RF antenna, uplink transmission data is sequentially processed at the low-PHY to the RRC layer. 
     In this embodiment, the foregoing protocol layer entities may be distributed to a CU and a DU, and there may be eight specific distribution manners shown in Table 1, but no limitation is imposed thereto. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Protocol Layer 
                   
               
               
                 Distribution 
               
               
                 Identifier 
                 Protocol Layer Distribution Manner 
               
               
                   
               
             
            
               
                 1 
                 The RRC layer is distributed to a CU, and all layers below the RRC are 
               
               
                   
                 distributed to a DU. 
               
               
                 2 
                 The PDCP layer and a layer above the PDCP layer are distributed to the CU, 
               
               
                   
                 and all layers below the PDCP layer are distributed to the DU. 
               
               
                 3 
                 The high-RLC layer and a layer above the high-RLC layer are distributed to 
               
               
                   
                 the CU, and all layers below the high-RLC layer are distributed to the DU. 
               
               
                 4 
                 The low-RLC layer and a layer above the low-RLC layer are distributed to 
               
               
                   
                 the CU, and all layers below the low-RLC layer are distributed to the DU. 
               
               
                 5 
                 The high-MAC layer and a layer above the high-MAC layer are distributed 
               
               
                   
                 to the CU, and all layers below the high-MAC layer are distributed to the 
               
               
                   
                 DU. 
               
               
                 6 
                 The low-MAC layer and a layer above the low-MAC layer are distributed to 
               
               
                   
                 the CU, and all layers below the low-MAC layer are distributed to the DU. 
               
               
                 7 
                 The high-PHY layer and a layer above the high-PHY layer are distributed to 
               
               
                   
                 the CU, and all layers below the high-PHY layer are distributed to the DU. 
               
               
                 8 
                 The low-PHY layer and a layer above the low-PHY layer are distributed to 
               
               
                   
                 the CU. 
               
               
                   
               
            
           
         
       
     
     In addition to the foregoing eight distribution manners, another protocol layer combination and distribution manner may also be defined. No limitation is imposed herein. The protocol layer distribution manner shown in Table 1 may be preconfigured by OAM, or may be specified by a related protocol. 
       FIG. 3  is a schematic flowchart of a protocol layer distribution indication method according to this application. As shown in  FIG. 3 , the method includes the following operations. 
     Operation S 301 . A CU determines a protocol layer distribution manner between the CU and a DU. 
     The CU may determine the protocol layer distribution manner between the CU and the DU based on a specific situation, a preset condition, or the like. Specifically, the protocol layer distribution manner may be selected from the plurality of distribution manners shown in Table 1, and certainly is not limited to Table 1. 
     In one embodiment, after determining the protocol layer distribution manner between the CU and the DU, the CU enables a corresponding protocol layer functional entity to process data. For example, when the protocol layer distribution manner determined by the CU is the distribution manner “3” shown in Table 1, the CU enables protocol layer entities at a high-RLC layer and at a layer above the high-RLC layer to process data. 
     Operation S 302 . The CU generates first protocol layer distribution information based on the protocol layer distribution manner. 
     Operation S 303 . The CU sends the first protocol layer distribution information to the DU. The DU receives the first protocol layer distribution information sent by the CU. 
     Operation S 304 . The DU determines the protocol layer distribution manner between the CU and the DU based on the first protocol layer distribution information. 
     Operation S 305 . The DU processes data based on the protocol layer distribution manner between the CU and the DU. 
     After receiving the first protocol layer distribution information, the DU may enable a corresponding protocol layer functional entity based on the protocol layer distribution manner indicated by the first protocol layer distribution information. 
     For example, if the protocol layer distribution manner indicated by the first protocol layer distribution information is the distribution manner “3” shown in Table 1, the DU enables protocol layer functional entities corresponding to all protocol layers below the high-RLC layer. 
     Herein, interaction between the CU and one DU communicatively connected to the CU is used as an example for description. The CU performs same interaction with another DU communicatively connected to the CU. 
     In this embodiment, the CU determines the protocol layer distribution manner between the CU and the DU, further generates the first protocol layer distribution information based on the protocol layer distribution manner, and sends the first protocol layer distribution information to the DU, so that the protocol layer distribution manner can be dynamically determined, and dynamically notified to the DU. The DU may also change a protocol layer distribution in a timely manner based on the received first protocol layer distribution information. 
     In a specific implementation process, the CU may send the first protocol layer distribution information to the DU in a plurality of manners, or may send the first protocol layer distribution information to the DU in different occasions. 
       FIG. 4  is a schematic flowchart of another protocol layer distribution indication method according to this application. In this embodiment, a CU adds first protocol layer distribution information to an interface setup request or an interface update request. Referring to  FIG. 4 , the interface setup request is used as an example (all of the following interface setup requests may be replaced with the interface update request), and the method includes the following operations. 
     Operation S 401 . The CU sends the interface setup request to a DU, where the interface setup request includes first protocol layer distribution information. 
     Operation S 402 . The DU sends an interface setup response to the CU. 
     Further, an interface between the CU and the DU is set up. Specifically, the interface may be an XCRAN interface. No limitation is imposed herein. 
     Operation S 403 . The CU sends a bearer setup request to a core network. 
     Operation S 404 . The core network sends a bearer setup response to the CU. 
     The bearer setup response carries bearer setup-related information. 
     Operation S 405 . The CU sends a DU addition request (DU addition request) to the DU, where the DU addition request carries bearer setup-related information. 
     Operation S 406 . The DU sends a DU addition response (DU addition response) to the CU. 
     After bearer setup between the CU and the DU is completed, a data packet may be transmitted. 
     In one embodiment, when determining a protocol layer distribution manner, the CU may determine to perform protocol layer distribution based on quality level information. 
     The first protocol layer distribution information includes a mapping relationship between quality level information and protocol layer distribution information. 
     The quality level information may be a QCI (QoS Class Identifier), and a QCI and a mapping relationship between a quality of service (QoS) parameter and the QCI are specified in a protocol. 
     For details of the interface setup request, refer to Table 2. 
     
       
         
           
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
             
            
               
                   
                 Information Element (IE)/Group Name (Group Name) 
               
               
                   
                 Information type 
               
               
                   
                 CU identifier 
               
               
                   
                 Serving Cell 
               
               
                   
                 &gt;Serving cell information 
               
               
                   
                 Protocol layer Distribution Information Table 
               
               
                   
                 &gt;Mapping relationship between a QCI and protocol 
               
               
                   
                 layer distribution information 
               
               
                   
                 &gt;&gt;QCI 
               
               
                   
                 &gt;&gt;Protocol layer distribution information 
               
               
                   
                   
               
            
           
         
       
     
     It can be learned that the interface setup request in Table 2 includes a protocol layer distribution information table, and the protocol layer distribution information table includes a mapping relationship between a QCI and protocol layer distribution information. Protocol layer distribution information corresponding to different QCIs is specifically recorded in the mapping relationship. 
     The mapping relationship between the QCI and the QoS parameter may be shown in Table 3. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                   
                 Data Packet 
                   
               
               
                 QCI 
                 Resource Type 
                 Priority 
                 Latency 
                 Packet Loss Rate 
               
               
                   
               
             
            
               
                 1 (NOTE 3) 
                 GBR 
                 7 
                 100 ms 
                 10 −2   
               
               
                 2 (NOTE 3) 
                   
                 4 
                 150 ms 
                 10 −3   
               
               
                 3 (NOTE 3) 
                   
                 3 
                  50 ms 
                 10 −3   
               
               
                 4 (NOTE 3) 
                   
                 5 
                 300 ms 
                 10 −6   
               
               
                 5 (NOTE 3) 
                 Non-GBR 
                 1 
                 100 ms 
                 10 −6   
               
               
                 6 (NOTE 4) 
                   
                 6 
                 300 ms 
                 10 −6   
               
               
                 7 (NOTE 3) 
                   
                 7 
                 100 ms 
                 10 −3   
               
               
                 8 (NOTE 5) 
                   
                 8 
                 300 ms 
                 10 −6   
               
               
                 9 (NOTE 6) 
                   
                 9 
               
               
                   
               
            
           
         
       
     
     A GBR is a guaranteed bit rate (Guaranteed Bit Rate), and represents a minimum bit rate, guaranteed by a system, of a bearer. Each QCI corresponds to a group of QoS parameters in the following. 
     After the bearer setup between the CU and the DU is completed, the DU may determine a corresponding QCI based on a current QoS parameter, and further obtain corresponding protocol layer distribution information based on the mapping relationship between the QCI and the protocol layer distribution information, so as to determine the protocol layer distribution manner. 
     For example, the protocol layer distribution information is a protocol layer distribution identifier. If the protocol layer distribution identifier is “2” shown in Table 2, the DU may determine that the current protocol layer distribution manner is “A PDCP layer and a layer above the PDCP layer are distributed to the CU, and all layers below the PDCP layer are distributed to the DU”. 
     In one embodiment, a protocol layer distribution may be at a slice level. The first protocol layer distribution information includes a mapping relationship between slice information and protocol layer distribution information. 
     The CU can determine that different slices correspond to different protocol layer distribution. After the CU sends the first protocol layer distribution information to the DU and the bearer setup between the CU and the DU is completed the DU can determine a protocol layer distribution manner based on specific slice information and the mapping relationship between the slice information and the protocol layer distribution information, and process data based on the protocol layer distribution manner. 
     Optionally, the interface setup request may alternatively be shown in Table 4. 
     
       
         
           
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
             
            
               
                   
                 IE/Group Name 
               
               
                   
                 Information type 
               
               
                   
                 CU identifier 
               
               
                   
                 Serving Cell 
               
               
                   
                 &gt;Serving cell information 
               
               
                   
                 Protocol Layer Distribution Information Table 
               
               
                   
                 &gt;Mapping relationship between slice information and 
               
               
                   
                 protocol layer distribution information 
               
               
                   
                 &gt;&gt;Slice information 
               
               
                   
                 &gt;&gt;Protocol layer distribution information 
               
               
                   
                   
               
            
           
         
       
     
     It can be learned that the interface setup request in Table 4 includes a protocol layer distribution information table, and the protocol layer distribution information table includes a mapping relationship between slice information and protocol layer distribution information. Protocol layer distribution information corresponding to different slice information is specifically recorded in the mapping relationship. 
     A network slice is a slice selected depending on a requirement of an operator or a user, and different network slice requirements (network slice instance) are used to support different services or different tenants. 
     The slice information herein may be a slice identifier (ID) or a slice parameter. The slice ID may be specified by a protocol, may be specified by a network management system (for example, Operation Administration and Maintenance, OAM), or may be specified by an interface between the CU and the DU. No limitation is imposed herein. For example, slice ID=1 represents a specific service of a particular tenant. The slice parameter may include tenant (tenancy) specific information, service type information, or the like. 
     In one embodiment, the CU may alternatively determine the protocol layer distribution manner between the CU and the DU at a CU level or a DU level. 
     If the CU determines the protocol layer distribution manner at the CU level, a plurality of DUs communicatively connected to the CU use the same protocol layer distribution manner. If the CU determines the protocol layer distribution manner at the DU level, a plurality of DUs communicatively connected to the CU may use the same protocol layer distribution manner or different protocol layer distribution manners. 
     In one embodiment, for the CU level, when determining the protocol layer distribution manner between the CU and the DU, the CU may determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the CU and a protocol layer distribution manner. 
     The mapping relationship between the CU and the protocol layer distribution manner may be preset in the CU. The mapping relationship between the CU and the protocol layer distribution manner may specifically include a CU ID and a corresponding protocol layer distribution identifier. The CU may determine the corresponding protocol layer distribution identifier based on the ID of the CU, and further packetize the corresponding protocol layer distribution identifier to generate first protocol layer distribution information. 
     The interface setup request may be shown in Table 5. 
     
       
         
           
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
             
            
               
                   
                 IE/Group Name 
               
               
                   
                 Information type 
               
               
                   
                 CU ID 
               
               
                   
                 Serving Cell 
               
               
                   
                 &gt;Serving cell type 
               
               
                   
                 Protocol Layer Distribution Information 
               
               
                   
                 &gt;Protocol layer distribution ID 
               
               
                   
                   
               
            
           
         
       
     
     It can be learned that the interface setup request carries a CU identifier, and corresponding protocol layer distribution information carries a protocol layer distribution ID. 
     In one embodiment, for the DU level, the CU determines the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the DU and a protocol layer distribution manner. 
     In one embodiment, the mapping relationship between the DU and the protocol layer distribution manner may be preset in the CU, and the mapping relationship between the DU and the protocol layer distribution manner includes a DU ID and a corresponding protocol layer distribution ID. The CU can determine, based on an ID of a DU communicatively connected to the CU, a protocol layer distribution ID corresponding to each DU; and further generate corresponding first protocol layer distribution information, and send the first protocol layer distribution information to a corresponding DU. In this case, protocol layer distribution information received by each DU is protocol layer distribution information corresponding to the DU. 
     The first protocol layer distribution information is similar to that in Table 5. Based on Table 5, the first protocol layer information further carries a DU ID of the DU that receives the first protocol layer distribution information. 
     In another embodiment, the DU addition request carries the first protocol layer distribution information. A specific method process is the same as that shown in  FIG. 4 . The interface setup request in operation S 401  no longer includes the first protocol layer distribution information, but the first protocol layer distribution information is included in the DU addition request in operation S 405 . 
     In one embodiment, the first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate a currently used protocol layer distribution manner to the DU. 
     Different from the foregoing embodiment, a mapping relationship is not sent herein. Instead, an indication is directly carried. After receiving the first protocol layer distribution information, the DU directly determines the protocol layer distribution manner based on the first protocol layer distribution indication. 
     The first protocol layer distribution indication may be the protocol layer distribution identifier (protocol layer distribution ID) shown in Table 1, or may be other information used to indicate the protocol layer distribution identifier. No limitation is imposed herein. 
     In one embodiment, the CU may determine the protocol layer distribution manner based on a terminal to be served. To be specific, the CU may determine the protocol layer distribution manner based on an identifier of the terminal to be served and a mapping relationship between the terminal and a protocol layer distribution manner. For example, when terminal ID=0, protocol layer distribution ID=4; or when terminal ID=1, protocol layer distribution ID=5. 
     The DU addition request further includes information about the terminal to be served, for example, the ID of the terminal to be served. 
     The DU addition request may be shown in Table 6. 
     
       
         
           
               
               
             
               
                   
                 TABLE 6 
               
               
                   
                   
               
             
            
               
                   
                 IE/Group Name 
               
               
                   
                 Information type 
               
               
                   
                 Terminal ID 
               
               
                   
                 (Slice ID) 
               
               
                   
                 Protocol layer distribution ID 
               
               
                   
                 List of E-RABs Allowed To Be Added 
               
               
                   
                 &gt;E-RAB allowed to be added 
               
               
                   
                 &gt;&gt;E-RAB ID 
               
               
                   
                 &gt;&gt;QoS parameter at an E-RAB level 
               
               
                   
                   
               
            
           
         
       
     
     It can be learned that the DU addition request includes a terminal ID and a corresponding protocol layer distribution ID. Optionally, slice information such as a slice ID may alternatively be included. 
     In one embodiment, the DU addition request may further include bearer information. It can be learned from Table 5 that the CU may further add bearer-related information to the DU addition request and send the DU addition request to the DU. The bearer-related information in the example of Table 5 is related information of an evolved UMTS terrestrial radio access network (Evolved UMTS Terrestrial Radio Access Network, E-UTRAN) radio access bearer (E-UTRAN radio access bearer). 
     When determining the protocol layer distribution manner between the CU and the DU, the CU may alternatively determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the bearer information and a protocol layer distribution manner. For example, when E-RAB ID=0, protocol layer distribution ID=6; or when E-RAB ID=1, protocol layer distribution ID=7. 
     In one embodiment, the DU addition request may further include slice information. When determining the protocol layer distribution manner between the CU and the DU, the CU may determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the slice information and a protocol layer distribution manner. For example, when slice ID=0, protocol layer distribution ID=6; or when slice ID=1, protocol layer distribution ID=7. 
     The DU addition request may be shown in Table 7. 
     
       
         
           
               
               
             
               
                   
                 TABLE 7 
               
               
                   
                   
               
             
            
               
                   
                 IE/Group Name 
               
               
                   
                 Information type 
               
               
                   
                 Terminal ID 
               
               
                   
                 Slice ID 
               
               
                   
                 Protocol layer distribution ID 
               
               
                   
                 List of E-RABs Allowed To Be Added 
               
               
                   
                 &gt;E-RAB allowed to be added 
               
               
                   
                 &gt;&gt;E-RAB ID 
               
               
                   
                 &gt;&gt;QoS parameter at an E-RAB level 
               
               
                   
                   
               
            
           
         
       
     
     After receiving the DU addition request, the DU can determine the protocol layer distribution manner between the CU and the DU according to the DU addition request. 
     Optionally, the DU addition request may further include data flow (flow) information. 
     When determining the protocol layer distribution manner between the CU and the DU, the CU may determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the flow information and a protocol layer distribution ID. 
     The flow information may be a flow ID or a flow parameter. No limitation is imposed herein. 
     For example, when flow ID=0, protocol layer distribution ID=6; or when flow ID=1, protocol layer distribution ID=7. 
     The DU addition request may be shown in Table 8. 
     
       
         
           
               
               
             
               
                   
                 TABLE 8 
               
               
                   
                   
               
             
            
               
                   
                 IE/Group Name 
               
               
                   
                 Information type 
               
               
                   
                 Terminal ID 
               
               
                   
                 List of Flows Allowed To Be Added 
               
               
                   
                 &gt;Flow allowed to be added 
               
               
                   
                 &gt;&gt;Flow ID or flow parameter 
               
               
                   
                 &gt;&gt;Protocol layer distribution ID 
               
               
                   
                   
               
            
           
         
       
     
     It can be learned that the DU addition request includes flow information and a corresponding protocol layer distribution ID. After receiving the DU addition request, the DU can determine the protocol layer distribution manner between the CU and the DU according to the DU addition request. 
     It should be noted that the flow parameter herein may be a QoS parameter corresponding to each data flow, in other words, referring to the QoS parameter shown in Table 3. 
     Based on the foregoing embodiment, the first protocol layer distribution information includes uplink protocol layer distribution information and downlink protocol layer distribution information. 
     A form of the uplink protocol layer distribution information is the same as that of the downlink protocol layer distribution information. Two pieces of information may be carried with reference to the foregoing carrying method, and each piece of information includes an uplink identifier or a downlink identifier. 
     For example, the uplink protocol layer distribution information includes an uplink identifier and a mapping relationship between quality level information and protocol layer distribution information. The downlink protocol layer distribution information includes a downlink identifier and a mapping relationship between quality level information and protocol layer distribution information. 
     Alternatively, in a message that carries the uplink protocol layer distribution information and the downlink protocol layer distribution information, the uplink protocol layer distribution information and the downlink protocol layer distribution information are arranged in a preset order, and the uplink protocol layer distribution information is followed by the downlink protocol layer distribution information. For example, the DU addition request carries two protocol distribution indications. A first protocol distribution indication is used to indicate an uplink protocol layer distribution, and a second protocol layer distribution indication is used to indicate a downlink protocol layer distribution. No limitation is imposed herein. 
     Further, the CU may further add the first protocol layer distribution information to a data packet. The first protocol layer distribution information includes the downlink protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate, to the DU, a protocol layer distribution manner used by the current data packet. The first protocol layer distribution indication may be a protocol layer distribution ID. 
     This manner is usually applicable to downlink data transmission. After determining the protocol layer distribution manner between the CU and the DU, the CU first processes data by using a protocol layer distributed to the CU, and then sends data to the DU. The DU determines the protocol layer distribution manner between the CU and the DU based on the first protocol layer distribution information in the data packet, and enables a protocol layer entity distributed to the DU to process data. 
     For example, if the protocol layer distribution manner determined by the CU is “4” in Table 1, that is, “a low-RLC layer and a layer above the low-RLC layer are distributed to the CU, and all layers below the low-RLC layer are distributed to the DU”, the CU processes to-be-processed data at “an RRC layer to the low-RLC layer”, and then packetizes the to-be-processed data into a data packet. The data packet carries “protocol layer distribution ID=4”. After receiving the data packet, the DU first parses the data packet to obtain “protocol layer distribution ID=4”, and then processes the to-be-processed data at “a high-MAC layer to a low-PHY layer”. 
     The first protocol layer distribution information may be carried in a header of the data packet. Correspondingly, the CU further receives a data packet sent by the DU, and the data packet carries second protocol layer distribution information. 
     The second protocol layer distribution information includes the second protocol layer distribution indication used to indicate, to the CU, a protocol layer distribution manner used by the current data packet. The second protocol layer distribution indication may be a protocol layer distribution ID. 
     Based on the foregoing embodiment, an enabled function at each protocol layer may be further flexibly adjusted. 
     The CU determines a to-be-enabled function at each protocol layer, and generates function indication information. The CU sends the function indication information to the DU, and the DU enables, based on the function indication information, a function corresponding to each protocol layer. 
     Likewise, after determining the to-be-enabled function at each protocol layer, the CU also adjusts a function enabled at a protocol layer distributed to the CU. 
     For example, an RLC layer includes a function of cascading, segmenting, or reassembling an RLC service data unit (SDUs). For an enhanced mobile broadband (eMBB) service in new radio (NR), the function may need to be disabled at the RLC and implemented at a MAC layer. For a massive machine type communications (mMTC) service, the function may also be disabled at the RLC in case of uncommon small-packet transmission. The RLC does not need the function for an ultra-reliable and low-latency communications (URLLC) service. 
       FIG. 5  is a schematic flowchart of another protocol layer distribution indication method according to this application. A protocol layer distribution manner between a CU and a DU may be further determined by the DU. After determining the protocol layer distribution manner, the DU notifies the CU of the protocol layer distribution manner. As shown in  FIG. 5 , the method includes the following operations: 
     Operation S 501 . The DU determines the protocol layer distribution manner between the CU and the DU. 
     Operation S 502 . The DU generates second protocol layer distribution information based on the protocol layer distribution manner between the CU and the DU. 
     Operation S 503 . The DU sends the second protocol layer distribution information to the CU. 
     Operation S 504 . The CU determines the protocol layer distribution manner between the CU and the DU based on the second protocol layer distribution information. 
     Operation S 505 . The CU processes data based on the protocol layer distribution manner between the CU and the DU. 
     In this embodiment, the DU sends the second protocol layer distribution information to the CU, to notify the CU of the protocol layer distribution manner between the CU and the DU. In this case, the protocol layer distribution manner is dynamically determined, and dynamically notified to the CU. The CU and the DU may flexibly change a protocol layer distribution in a timely manner. 
     For a specific interaction process, refer to  FIG. 4 . Details are not described herein again. 
     The second protocol layer distribution information may be carried in an interface setup response. 
     In one embodiment, the second protocol layer distribution information includes a mapping relationship between quality level information and protocol layer distribution information; and 
     after bearer setup between the CU and the DU is completed, the CU may determine a corresponding QCI based on a current QoS parameter, and further obtain corresponding protocol layer distribution information based on the mapping relationship between the QCI and the protocol layer distribution information, so as to determine the protocol layer distribution manner; or 
     the second protocol layer distribution information includes a mapping relationship between slice information and protocol layer distribution information; and 
     after bearer setup between the CU and the DU is completed, the CU may determine a protocol layer distribution manner based on specific slice information and the mapping relationship between the slice information and the protocol layer distribution information, and process data based on the protocol layer distribution manner. 
     An implementation of the protocol layer distribution manner is similar to that in the foregoing embodiment. Details are not described herein again. 
     In one embodiment, the second protocol layer distribution information may be carried in a DU addition response. 
     In one embodiment, the second protocol layer distribution information may include a second protocol layer distribution indication, and the second protocol layer distribution indication is used to indicate a currently used protocol layer distribution manner to the CU. 
     The second protocol layer distribution indication may be the protocol layer distribution identifier (protocol layer distribution ID) shown in Table 1, or may be other information used to indicate the protocol layer distribution identifier. No limitation is imposed herein. 
     In one embodiment, the DU may determine the protocol layer distribution manner based on a terminal to be served. To be specific, the DU may determine the protocol layer distribution manner based on an identifier of the terminal to be served and a mapping relationship between the terminal and a protocol layer distribution manner. For example, when terminal ID=0, protocol layer distribution ID=4; or when terminal ID=1, protocol layer distribution ID=5. 
     The DU addition response further includes information about the terminal to be served, for example, the ID of the terminal to be served. 
     In one embodiment, when determining the protocol layer distribution manner between the CU and the DU, the DU may alternatively determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between bearer information and a protocol layer distribution manner. For example, when E-RAB ID=0, protocol layer distribution ID=6; or when E-RAB ID=1, protocol layer distribution ID=7. 
     In one embodiment, the DU addition response may further include bearer information. 
     In one embodiment, when determining the protocol layer distribution manner between the CU and the DU, the DU may determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between slice information and a protocol layer distribution manner. For example, when slice ID=0, protocol layer distribution ID=6; or when slice ID=1, protocol layer distribution ID=7. 
     In one embodiment, when determining the protocol layer distribution manner between the CU and the DU, the DU may determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between flow information and a protocol layer distribution ID. 
     The flow information may be a flow ID or a flow parameter. No limitation is imposed herein. 
     For example, when flow ID=0, protocol layer distribution ID=6; or when flow ID=1, protocol layer distribution ID=7. 
     In one embodiment, the DU addition response may further include data flow (flow) information. 
     The second protocol layer distribution information includes uplink protocol layer distribution information and downlink protocol layer distribution information. This is similar to the first protocol layer distribution information. Details are not described herein again. 
     In one embodiment, the second protocol layer distribution information may be carried in a data packet. 
     The DU sends the data packet to the CU, and the data packet carries the second protocol layer distribution information. In this case, the second protocol layer distribution information includes uplink protocol layer distribution information. 
     In one embodiment, the DU receives a data packet sent by the CU, and the data packet carries first protocol layer distribution information. In this case, the first protocol layer distribution information includes downlink protocol layer distribution information. 
     For a specific implementation process, refer to the foregoing method embodiment. Details are not described herein again. 
       FIG. 6  is a schematic structural diagram of a protocol layer distribution indication apparatus according to this application. The apparatus may be integrated into the foregoing CU. As shown in  FIG. 6 , the apparatus includes a processor  601 , a transmitter  602 , a receiver  603 , a memory  604 , and an antenna  605 . 
     The memory  604 , the transmitter  602 , the receiver  603 , and the processor  601  may be connected by using a bus. Certainly, in actual application, the memory  604 , the transmitter  602 , the receiver  603 , and the processor  601  may not be of a bus structure, but may be of another structure such as a star-shaped structure. This is not specifically limited in this application. 
     In one embodiment, the processor  601  may be specifically a general-purpose central processing unit or an ASIC, may be one or more integrated circuits configured to control program execution, may be a hardware circuit developed by using an FPGA, or may be a baseband processor. 
     In one embodiment, the processor  601  may include at least one processing core. 
     In one embodiment, the memory  604  may include one or more of a ROM, a RAM, and a magnetic disk memory. The memory  604  is configured to store data and/or an instruction required when the processor  601  runs. There may be one or more memories  604 . 
     The apparatus may be configured to perform any method in the foregoing method embodiments. Details are as follows. 
     The processor  601  is configured to: determine a protocol layer distribution manner between a central unit CU and a distributed unit DU, and generate first protocol layer distribution information based on the protocol layer distribution manner. 
     The transmitter  602  is configured to send the first protocol layer distribution information to the DU. 
     In this embodiment, the CU determines the protocol layer distribution manner between the CU and the DU, further generates the first protocol layer distribution information based on the protocol layer distribution manner, and sends the first protocol layer distribution information to the DU, so that the protocol layer distribution manner can be dynamically determined, and dynamically notified to the DU. The DU may also change a protocol layer distribution in a timely manner based on the received first protocol layer distribution information. 
     The transmitter  602  is configured to send an interface setup request to the DU, where the interface setup request includes the first protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a mapping relationship between quality level information and protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a mapping relationship between slice information and protocol layer distribution information. 
     In one embodiment, the processor  601  is specifically configured to: determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the CU and a protocol layer distribution manner; or determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the DU and a protocol layer distribution manner. 
     The transmitter  602  is specifically configured to send a DU addition request to the DU, where the DU addition request includes the first protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate a currently used protocol layer distribution manner to the DU. 
     In one embodiment, the DU addition request further includes information about a terminal to be served. 
     In one embodiment, the first protocol layer distribution information includes uplink protocol layer distribution information and downlink protocol layer distribution information. 
     The transmitter  602  is specifically configured to send a data packet to the DU, where the data packet includes the first protocol layer distribution information, and the first protocol layer distribution information includes downlink protocol layer distribution information. 
     The first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate, to the DU, a protocol layer distribution manner used by the data packet. 
     In one embodiment, the receiver  603  is configured to receive a data packet sent by the DU, where the data packet includes second protocol layer distribution information, and the second protocol layer distribution information includes uplink protocol layer distribution information. 
     The second protocol layer distribution information includes a second protocol layer distribution indication, and the second protocol layer distribution indication is used to indicate, to the DU, a protocol layer distribution manner used by the data packet. 
     In one embodiment, the processor  601  is further configured to: determine a to-be-enabled function at each protocol layer, and generate function indication information. 
     The transmitter  602  is further configured to send the function indication information to the DU. 
     The apparatus is configured to execute the method embodiments executed by the foregoing terminal, and an implementation principle and a technical effect of the apparatus are similar to those of the method embodiment. For related content, refer to the method embodiments. Details are not described herein again. 
       FIG. 7  is a schematic structural diagram of another protocol layer distribution indication apparatus according to this application. The apparatus may be integrated into the foregoing DU. As shown in  FIG. 7 , the apparatus includes a processor  701 , a transmitter  702 , a receiver  703 , a memory  704 , and an antenna  705 . 
     The memory  704 , the transmitter  702 , the receiver  703 , and the processor  701  may be connected by using a bus. Certainly, in actual application, the memory  704 , the transmitter  702 , the receiver  703 , and the processor  701  may not be of a bus structure, but may be of another structure such as a star-shaped structure. This is not specifically limited in this application. 
     In one embodiment, the processor  701  may be specifically a general-purpose central processing unit or an ASIC, may be one or more integrated circuits configured to control program execution, may be a hardware circuit developed by using an FPGA, or may be a baseband processor. 
     In one embodiment, the processor  701  may include at least one processing core. 
     In one embodiment, the memory  704  may include one or more of a ROM, a RAM, and a magnetic disk memory. The memory  704  is configured to store data and/or an instruction required when the processor  701  runs. There may be one or more memories  704 . 
     The apparatus may be configured to perform any method in the foregoing method embodiments. Details are as follows. 
     The receiver  703  is configured to receive first protocol layer distribution information sent by a central unit CU. 
     The processor  701  is configured to: determine a protocol layer distribution manner between the CU and a distributed unit DU based on the first protocol layer distribution information, and process data based on the protocol layer distribution manner between the CU and the DU. 
     In one embodiment, the receiver  703  is specifically configured to receive an interface setup request sent by the CU, where the interface setup request includes the first protocol layer distribution information. 
     In one embodiment, the receiver  703  is specifically configured to receive a DU addition request sent by the CU, where the DU addition request includes the first protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate a currently used protocol layer distribution manner to the DU. 
     In one embodiment, the receiver  703  is specifically configured to receive a data packet sent by the CU, where the data packet includes the first protocol layer distribution information, and the first protocol layer distribution information includes downlink protocol layer distribution information. 
     In one embodiment, the transmitter  702  is further configured to send a data packet to the CU, where the data packet includes second protocol layer distribution information, and the second protocol layer distribution information includes uplink protocol layer distribution information. 
     In another embodiment, referring to  FIG. 7 , the processor  701  is configured to: determine a protocol layer distribution manner between the CU and a DU, and generate second protocol layer distribution information based on the protocol layer distribution manner. 
     The transmitter  702  is configured to send the second protocol layer distribution information to the CU. 
     In one embodiment, the transmitter  702  sends an interface setup response to the CU, where the interface setup response includes the second protocol layer distribution information. 
     In one embodiment, the transmitter  702  sends a DU addition response to the CU, where the DU addition response includes the second protocol layer distribution information. 
     The apparatus is configured to execute the method embodiments executed by the foregoing terminal, and an implementation principle and a technical effect of the apparatus are similar to those of the method embodiment. For related content, refer to the method embodiments. Details are not described herein again. 
       FIG. 8  is a schematic structural diagram of another protocol layer distribution indication apparatus according to this application. The apparatus may be integrated into the foregoing CU. As shown in  FIG. 8 , the apparatus includes a determining module  801 , a generation module  802 , and a sending module  803 . 
     The determining module  801  is configured to determine a protocol layer distribution manner between a central unit CU and a distributed unit DU. 
     The generation module  802  is configured to generate first protocol layer distribution information based on the protocol layer distribution manner. 
     The sending module  803  is configured to send the first protocol layer distribution information to the DU. 
     In one embodiment, the sending module  803  is specifically configured to send an interface setup request to the DU, where the interface setup request includes the first protocol layer distribution information. 
     In one embodiment, the determining module  801  is specifically configured to: determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the CU and a protocol layer distribution manner; or determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the DU and a protocol layer distribution manner. 
     The first protocol layer distribution information includes a mapping relationship between quality level information and protocol layer distribution information. 
     In one embodiment, the first protocol layer distribution information includes a mapping relationship between slice information and protocol layer distribution information. 
     The sending module  803  is specifically configured to send a DU addition request to the DU, where the DU addition request includes the first protocol layer distribution information. 
     The first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate a currently used protocol layer distribution manner to the DU. 
     The sending module  803  is specifically configured to send a data packet to the DU, where the data packet includes the first protocol layer distribution information, and the first protocol layer distribution information includes downlink protocol layer distribution information. 
     The first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate, to the DU, a protocol layer distribution manner used by the data packet. 
       FIG. 9  is a schematic structural diagram of another protocol layer distribution indication apparatus according to this application. Based on  FIG. 8 , the apparatus may further include: a receiving module  804 , configured to receive a data packet sent by the DU, where the data packet includes second protocol layer distribution information, and the second protocol layer distribution information includes uplink protocol layer distribution information. 
     In one embodiment, the determining module  801  is further configured to: determine a to-be-enabled function at each protocol layer, and generate function indication information. The sending module  803  sends the function indication information to the DU. 
     The apparatus is configured to execute the method embodiments executed by the foregoing terminal, and an implementation principle and a technical effect of the apparatus are similar to those of the method embodiment. For related content, refer to the method embodiments. Details are not described herein again. 
       FIG. 10  is a schematic structural diagram of another protocol layer distribution indication apparatus according to this application. The apparatus may be integrated into the foregoing DU. As shown in  FIG. 10 , the apparatus includes a receiving module  110 , a determining module  111 , and a processing module  112 . 
     The receiving module  110  is configured to receive first protocol layer distribution information sent by a central unit CU. 
     The determining module  111  is configured to determine a protocol layer distribution manner between the CU and a distributed unit DU based on the first protocol layer distribution information. 
     The processing module  112  is configured to process data based on the protocol layer distribution manner between the CU and the DU. 
     In one embodiment, the receiving module  110  is specifically configured to receive an interface setup request sent by the CU, where the interface setup request includes the first protocol layer distribution information. 
     In one embodiment, the receiving module  110  is specifically configured to receive a DU addition request sent by the CU, where the DU addition request includes the first protocol layer distribution information. 
     The first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate a currently used protocol layer distribution manner to the DU. 
     The receiving module  110  is specifically configured to receive a data packet sent by the CU, where the data packet includes the first protocol layer distribution information, and the first protocol layer distribution information includes downlink protocol layer distribution information. 
     In one embodiment, the apparatus may further include a sending module, configured to send a data packet to the CU, where the data packet includes second protocol layer distribution information, and the second protocol layer distribution information includes uplink protocol layer distribution information. The second protocol layer distribution information includes a second protocol layer distribution indication, and the second protocol layer distribution indication is used to indicate, to the CU, a protocol layer distribution manner used by the data packet. 
     The receiving module  110  receives function indication information sent by the CU, where the function indication information is used to indicate a to-be-enabled function at each protocol layer. 
     The apparatus is configured to execute the method embodiments executed by the foregoing terminal, and an implementation principle and a technical effect of the apparatus are similar to those of the method embodiment. For related content, refer to the method embodiments. Details are not described herein again. 
     According to one embodiment, a protocol layer distribution indication apparatus includes: a determining module configured to determine a protocol layer distribution manner between a central unit (CU) and a distributed unit (DU); a generation module configured to generate first protocol layer distribution information based on the protocol layer distribution manner; and a sending module configured to send the first protocol layer distribution information to the DU. 
     The sending module is configured to send an interface setup request to the DU, wherein the interface setup request includes the first protocol layer distribution information. The first protocol layer distribution information includes a mapping relationship between quality level information and protocol layer distribution information. The first protocol layer distribution information includes a mapping relationship between slice information and protocol layer distribution information. The determining module is configured to: determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the CU and a protocol layer distribution manner, or determine the protocol layer distribution manner between the CU and the DU based on a mapping relationship between the DU and a protocol layer distribution manner. 
     The sending module is configured to send a DU addition request to the DU, wherein the DU addition request includes the first protocol layer distribution information. The first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate a currently used protocol layer distribution manner to the DU. The DU addition request further includes information about a terminal to be served. The first protocol layer distribution information includes uplink protocol layer distribution information and downlink protocol layer distribution information. The sending module is configured to send a data packet to the DU, wherein the data packet includes the first protocol layer distribution information, and the first protocol layer distribution information includes downlink protocol layer distribution information. 
     The first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate, to the DU, a protocol layer distribution manner used by the data packet. The apparatus further includes a receiving module, wherein the receiving module is configured to receive a data packet sent by the DU, wherein the data packet includes second protocol layer distribution information, and the second protocol layer distribution information includes uplink protocol layer distribution information. The determining module is further configured to: determine a to-be-enabled function at each protocol layer, and generate function indication information; and the sending module is further configured to send the function indication information to the DU. 
     According to another embodiment, a protocol layer distribution indication apparatus includes a receiving module configured to receive first protocol layer distribution information from a central unit (CU); a determining module configured to determine a protocol layer distribution manner between the CU and a distributed unit (DU) based on the first protocol layer distribution information; and a processing module configured to process data based on the protocol layer distribution manner between the CU and the DU. 
     The receiving module is configured to receive an interface setup request sent by the CU, wherein the interface setup request includes the first protocol layer distribution information. The receiving module is configured to receive a DU addition request sent by the CU, wherein the DU addition request includes the first protocol layer distribution information. The first protocol layer distribution information includes a first protocol layer distribution indication, and the first protocol layer distribution indication is used to indicate a currently used protocol layer distribution manner to the DU. The receiving module is configured to receive a data packet from the CU, wherein the data packet includes the first protocol layer distribution information, and the first protocol layer distribution information includes downlink protocol layer distribution information. 
     In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the described apparatus embodiment is merely an example. For example, the unit division is merely logical function division and may be other division in actual implementation. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or may not be performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented by using some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electrical, mechanical, or other forms. 
     The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed to a plurality of network units. Some or all of the units may be selected according to actual requirements to achieve the objectives of the solutions of the embodiments. 
     In addition, functional units in the embodiments of this application may be integrated into one processing unit, or each of the units may exist alone physically, or two or more units are integrated into one unit. The integrated unit may be implemented in a form of hardware, or may be implemented in a form of hardware in addition to a software functional unit. 
     When the foregoing integrated unit is implemented in a form of a software functional unit, the integrated unit may be stored in a computer-readable storage medium. The software functional unit is stored in a storage medium and includes several instructions for instructing a computer device (which may be a personal computer, a server, a network device, or the like) or a processor to perform some of the operations of the methods described in the embodiments of this application. The foregoing storage medium includes any medium that can store program code, such as a USB flash drive, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc. 
     Finally, it should be noted that the foregoing embodiments are merely intended for describing the technical solutions of this application other than limiting this application. Although this application is described in detail with reference to the foregoing embodiments, persons of ordinary skill in the art should understand that they may still make modifications to the technical solutions described in the foregoing embodiments or make equivalent replacements to some or all technical features thereof, without departing from the scope of the technical solutions of the embodiments of this application.