.. This work is licensed under a Creative Commons Attribution 4.0 International License.
.. http://creativecommons.org/licenses/by/4.0


########
API-Docs
########

This is the API-docs for I release o-du/l2.

.. contents::
   :depth: 3
   :local:

Introduction
============

This section tabulates the APIs Aligned(Implemented)/Not Implemented/Additional APIs between various modules of 
ODU-High and also with external modules of ORAN.

*****************
F1 Interface APIs
*****************

Below table lists APIs Aligned(Implemented)/Not Implemented at F1 interface of
ODU-High i.e. between O-DU and O-CU. These are in line with 3GPP 38.473 V15.3.0.

+------------+-------------------------------+-----------------+-----------+-----------------------------------------+
| Interface  |    API                        | Status          | Section   | Remark                                  |
+============+===============================+=================+===========+=========================================+
|            |Reset                          | Aligned         |9.2.1.1    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Reset Acknowledge              | Aligned         |9.2.1.2    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Error Indication               | Not Implemented |9.2.1.3    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |F1 Setup Request               | Aligned         |9.2.1.4    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |F1 Setup Response              | Aligned         |9.2.1.5    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |F1 Setup Failure               | Not Implemented |9.2.1.6    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |GNB-DU Configuration Update    | Aligned         |9.2.1.7    |                                         |
| **CU**     +-------------------------------+-----------------+-----------+-----------------------------------------+
| & **DU**   |GNB-DU Configuration Update    | Aligned         |9.2.1.8    |                                         |
|            |Acknowledge                    |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |GNB-DU Configuration Update    | Not Implemented |9.2.1.9    |                                         |
|            |Failure                        |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |GNB-CU Configuration Update    | Not Implemented |9.2.1.10   |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |GNB-CU Configuration Update    | Not Implemented |9.2.1.11   |                                         |
|            |Acknowledge                    |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |GNB-CU Configuration Update    | Not Implemented |9.2.1.12   |                                         |
|            |Failure                        |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |GNB-DU Resource Coordination   | Not Implemented |9.2.1.13   |                                         |
|            |Request                        |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |GNB-DU Resource Coordination   | Not Implemented |9.2.1.14   |                                         |
|            |Response                       |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |GNB-DU Status Indication       | Not Implemented |9.2.1.15   |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Context Setup Request       | Aligned         |9.2.2.1    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Context Setup Response      | Aligned         |9.2.2.2    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Context Setup Faliure       | Not Implemented |9.2.2.3    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Context Release Request     | Aligned         |9.2.2.4    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Context Release Command     | Aligned         |9.2.2.5    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Context Release Complete    | Aligned         |9.2.2.6    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Context Modification        | Aligned         |9.2.2.7    |                                         |
|            |Request                        |                 |           |                                         |  
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Context Modification        | Aligned         |9.2.2.8    |                                         |
|            |Response                       |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Context Modification        | Not Implemented |9.2.2.9    |                                         |
|            |Failure                        |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Context Modification        | Not Implemented |9.2.2.10   |                                         |
|            |Required                       |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Context Modification        | Not Implemented |9.2.2.11   |                                         |
|            |Confirm                        |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Inactivity Notification     | Not Implemented |9.2.2.12   |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Notify                         | Not Implemented |9.2.2.13   |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Initial UL RRC Message         | Aligned         |9.2.3.1    |                                         |
|            |Transfer                       |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |DL RRC Message Transfer        | Aligned         |9.2.3.2    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UL RRC Message Transfer        | Aligned         |9.2.3.3    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Write-Replace Warning Request  | Not Implemented |9.2.4.1    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Write-Replace Warning Response | Not Implemented |9.2.4.2    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |PWS Cancel Request             | Not Implemented |9.2.4.3    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |PWS Cancel Response            | Not Implemented |9.2.4.4    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |PWS Restart Indication         | Not Implemented |9.2.4.5    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |PWS failure Indication         | Not Implemented |9.2.4.6    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |System Information Delivery    | Not Implemented |9.2.5.1    |                                         |
|            |Command                        |                 |           |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Paging                         | Aligned         |9.2.6.1    |                                         |
+------------+-------------------------------+-----------------+-----------+-----------------------------------------+

*****************
E2 Interface APIs
*****************

This section tabulates the APIs Aligned(Implemented)/Not Implemented between ODU-High and Near-RT RIC.
These are in line with O-RAN.WG3.E2GAP-R003-v03.00 and O-RAN.WG3.E2AP-R003-v03.00.
Below mentioned section number are taken reference from sections of O-RAN.WG3.E2AP-R003-v03.00.

+------------+-------------------------------+-----------------+-----------+-----------------------------------------+
| Interface  |    API                        | Status          |Section    | Remark                                  |
+============+===============================+=================+===========+=========================================+
|            |RIC Subscription procedure     | Aligned         |8.2.1      |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RIC Subscription Delete        | Aligned         |8.2.2      |                                         |
|            |procedure                      |                 |           |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RIC Subscription Delete        | Aligned         |8.2.2A     |                                         |
|            |Required procedure             |                 |           |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RIC Indication procedure       | Aligned         |8.2.3      |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RIC Control procedure          | Not Implemented |8.2.4      |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RIC Subscription Modification  | Aligned         |8.2.5      |                                         |
|            |procedure                      |                 |           |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
| **DU**     |RIC Subscription Modification  | Aligned         |8.2.6      |                                         |
| &**RIC**   |Required procedure             |                 |           |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RIC query procedure            | Not Implemented |8.2.7      |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |E2 Setup procedure             | Aligned         |8.3.1      |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Reset procedure                | Aligned         |8.3.2      |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Error Indication               | Aligned         |8.3.3      |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RIC Service Update procedure   | Aligned         |8.3.4      |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |E2 Node Configuration Update   | Aligned         |8.3.5      |                                         |
|            |procedure                      |                 |           |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |E2 Connection Update procedure | Aligned         |8.3.6      |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |E2 Removal procedure           | Aligned         |8.3.7      |                                         |
+------------+-------------------------------+-----------------+-----------+-----------------------------------------+

********************************
ODU-High Internal Interface APIs
********************************

Below table lists APIs Aligned(Implemented)/Not Implemented/Additional APIs between various modules of ODU-High. 
These are in line with ORAN-WG8.AAD-v9.00.00, hereafter referred to as AAD Spec.

Note: DU APP module consist functionality related to F1 Handler, E2 Handler and O1 Handler.

+------------+-------------------------------+-----------------+-----------+-----------------------------------------+
| Interface  |    API                        | Status          | Section   | Remark                                  |
+============+===============================+=================+===========+=========================================+
|            |Cell Configuration             | Aligned         |11.2.1.1   |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slice Configuration            | Aligned         |11.2.1.2   |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Bring Cell Up                  | Additional API  |           |Notify DU to bring specific cell up      |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|**SMO-OAM** |Bring Cell Down                | Additional API  |           |Notify DU to bring specific cell down    |
|& **DU APP**+-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slice PM                       | Additional API  |           |DU APP sends PM for all Slices every 60s |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Raise Cell Alarm               | Additional API  |           |DU APP alarms during cell state change   |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Set the cell operational state | Additional API  |           |DU APP inform cell state[ACTIVE/INACTIVE]|
+------------+-------------------------------+-----------------+-----------+-----------------------------------------+
|            |DL Transfer                    | Aligned         |11.2.3.1   |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UL Transfer                    | Aligned         |11.2.3.2   |                                         |
| **RLC**    +-------------------------------+-----------------+-----------+-----------------------------------------+
| & **MAC**  |Schedule Result Reporting(DL)  | Aligned         |11.2.3.3   |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Buffer Status Report(UL)       | Aligned         |11.2.3.4   |                                         |
+------------+-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Air Interface Time             | Aligned         |11.2.4.1.1 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Cell Configuration Request     | Aligned         |11.2.4.2.1 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Cell Delete Request            | Aligned         |11.2.4.2.2 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slice Configuration Request    | Aligned         |11.2.4.2.3 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slice Reconfiguration Request  | Aligned         |11.2.4.2.4 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Add UE Configuration Request   | Aligned         |11.2.4.2.5 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Reconfiguration Request     | Aligned         |11.2.4.2.6 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Delete UE Request              | Aligned         |11.2.4.2.7 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |DL HARQ Indication             | Aligned         |11.2.4.2.8 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UL Harq Indication(CRC)        | Aligned         |11.2.4.2.9 |                                         |
| **MAC** to +-------------------------------+-----------------+-----------+-----------------------------------------+
|  **SCH**   |UL Channel Quality Information | Not Implemented |11.2.4.2.10|                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |DL Channel Quality Information | Not Impelemented|11.2.4.2.11|                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RACH Indication Contents       | Aligned         |11.2.4.2.12|                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Paging Indication Contents     | Aligned         |11.2.4.2.13|                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RACH Resource Request          | Aligned         |11.2.4.2.14|                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RACH Resource Release          | Aligned         |11.2.4.2.15|                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |DL RLC Buffer Status Info      | Aligned         |11.2.4.2.16|                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Scheduling Request Indication  | Aligned         |11.2.4.2.17|                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UL Buffer Status Report Ind    | Aligned         |11.2.4.2.18|                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Power Headroom Indication      | Aligned         |11.2.4.2.19|                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Request             | Additional API  |           | Adding new statistics group             |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Modification Request| Additional API  |           | Modification of statistics group        |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Delete Request      | Additional API  |           | Deletion of statistics group            |
+------------+-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Cell Configuration Response    | Aligned         |11.2.4.3.1 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Cell Delete Response           | Aligned         |11.2.4.3.2 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slice Configuration Response   | Aligned         |11.2.4.3.3 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slice ReConfiguration Response | Aligned         |11.2.4.3.4 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Configuration Response      | Aligned         |11.2.4.3.5 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE ReConfiguration Response    | Aligned         |11.2.4.3.6 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Delete Response             | Aligned         |11.2.4.3.7 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
| **SCH** to |DL Scheduling Information      | Aligned         |11.2.4.3.8 |                                         |
|    **MAC** +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UL Scheduling Information      | Aligned         |11.2.4.3.9 |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RAR Information                | Not Required    |11.2.4.3.10|Included in DL Scheduling Info           |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Downlink Control Channel Info  | Not Required    |11.2.4.3.11|Included in DL Scheduling Info           |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Downlink Broadcast Allocation  | Not Required    |11.2.4.3.12|Included in DL Scheduling Info           |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Downlink Paging Allocation     | Aligned         |11.2.4.3.13|                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |HARQ Process Release           | Additional API  |           |SCH indicates MAC to release a HARQ      |
|            |                               |                 |           |process in case a positive acknowledement|
|            |                               |                 |           |is received or achieved maximum retrans. |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RACH Resource Response         | Additional API  |           |Response to RACH Resource Request for    |
|            |                               |                 |           |dedicated resource for CF-RA             |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Response            | Additional API  |           |Response to statistics request           |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Modification        | Additional API  |           |Response to statistics modification      |
|            |Resonse                        |                 |           |request                                  | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Delete Response     | Additional API  |           |Response to statistics delete request    |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Indication          | Additional API  |           |Calculate the KPI related to a specific  |
|            |                               |                 |           |statistics group                         | 
+------------+-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Cell Start                     | Aligned         |1.1.1.1    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Cell Stop                      | Aligned         |1.1.1.2    |                                         |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Cell Configuration Request     | Additional API  |           |Configures cell information at MAC.      | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Cell Configuration Response    | Additional API  |           |Response to cell Cfg Req from DUAPP      |    
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Cell Delete Request            | Additional API  |           |Deletes cell information at MAC.         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Cell Delete Response           | Additional API  |           |Response to Cell Del request from DU APP | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slice Configuration Request    | Additional API  |           |Configures Slice at MAC                  | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slice ReConfiguration Request  | Additional API  |           |ReConfigures Slice at MAC                | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slice Configuration Response   | Additional API  |           |Response to Slice Cfg req from DU APP    |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slice ReConfiguration Response | Additional API  |           |Response to Slice ReCfg req from DU APP  |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|**DU APP**  |UE Create Request              | Aligned         |1.1.1.3    |                                         | 
| & **MAC**  +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Create Response             | Aligned         |1.1.1.4    |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Reconfiguration Request     | Aligned         |1.1.1.5    |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Reconfiguration Response    | Aligned         |1.1.1.6    |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Delete Request              | Aligned         |1.1.1.7    |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Delete Response             | Aligned         |1.1.1.8    |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RACH Resource Request          | Aligned         |1.1.1.9    |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RACH Resource Response         | Aligned         |1.1.1.10   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RACH Resource Release          | Aligned         |1.1.1.11   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Reset Request               | Not Implemented |1.1.1.12   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Reset Response              | Not Implemented |1.1.1.13   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Sync Status Indication      | Not Implemented |1.1.1.14   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UL CCCH Indication             | Aligned         |1.1.1.15   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |DL CCCH Indication             | Aligned         |1.1.1.16   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |DL PCCH Indication             | Aligned         |1.1.1.17   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |DL Broadcast Request           | Not Implemented |1.1.1.18   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slot Indication                | Additional API  |           |Indication about the ongoing SFN and     |
|            |                               |                 |           | Slot information to DU APP              | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Request             | Additional API  |           | Adding new statistics at DU layer       |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Response            | Additional API  |           | Response to statistics request from MAC |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Modification Request| Additional API  |           | Modification of statistics at DU layer  |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Modification        | Additional API  |           | Response to statistics modification     |
|            |Response                       |                 |           | request from MAC                        | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Delete Request      | Additional API  |           | Deletion of statistics at DU layer      |
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Delete Response     | Additional API  |           | Response to statistics delete request   |
|            |                               |                 |           | from MAC                                | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Statistics Indication          | Additional API  |           | Sending the calculated KPI value to DU  |
|            |                               |                 |           | from MAC                                | 
+------------+-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Create                      | Aligned         |11.2.5.1   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Create Response             | Aligned         |11.2.5.2   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Reconfiguration             | Aligned         |11.2.5.3   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Reconfiguration Response    | Aligned         |11.2.5.4   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Delete                      | Aligned         |11.2.5.5   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UE Delete Response             | Aligned         |11.2.5.6   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |DL-RRC Message Transfer        | Aligned         |11.2.5.7   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UL-RRC Message Transfer        | Aligned         |11.2.5.8   |                                         | 
|**DU APP**  +-------------------------------+-----------------+-----------+-----------------------------------------+
|  & **RLC** |UL-RRC Message Delivery Report | Aligned         |11.2.5.9   |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |RLC Max Retransmission Reached | Not Implemented |11.2.5.10  |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UL-RLC Re-establishment Request| Not Implemented |11.2.5.11  |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UL-RLC Re-establshment Response| Not Implemented |11.2.5.12  |                                         | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |DL RRC Message Response        | Additional API  |           |Informs DU APP if a DL RRC Message was   |
|            |                               |                 |           |successfuly procesed at RLC & sent to MAC| 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |DL User Data                   | Additional API  |           |DL user data exchanged from DUAPP to RLC | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |UL User Data                   | Additional API  |           |UL user data exchanged from RLC to DUAPP | 
|            +-------------------------------+-----------------+-----------+-----------------------------------------+
|            |Slice Performance Metrics      | Additional API  |           |Performance Metrics informed to DUAPP    |
|            |                               |                 |           |every 60sec for every slice configured   | 
+------------+-------------------------------+-----------------+-----------+-----------------------------------------+