1. Cu events

1.1 Introduction¶

There are a number of dRAX RAN Events that are useful to monitor for. The dRAX RAN Events are messages that are distributed over the dRAX Databus.

Specifically, you can subscribe to the following topic on the dRAX Databus:

dRAX RAN Events topic on the dRAX Databus

accelleran.drax.5g.ric.raw.messages

This is a generic topic, where all the messages from the Accelleran CU are published. Hence, you need to filter the messages, to get the dRAX RAN Events only. To do so, each message on this dRAX Databus topic has a ‘topic’ field as a root key in the JSON. You can then filter based on this field.

Details on the topic field

The ‘topic’ field in the JSON messages can contain additional strings aside from the above mentioned. Therefore, it's best to check if the above string is part of the ‘topic’ field.

The xApp Templates have example code how to filter the dRAX RAN Events messages. Here is a short snippet:

Example

### Example: Monitoring dRAX Events
# Listen to the dRAX Databus
(topic, data) = xapp.kafka().json().recv_message()

# List of dRAX Events:
drax_events = [
    'F1-SEIZE-REQUEST',
    'F1-SCTP-ASSOC-FAILURE-IND.DU',
    'F1-ASSOC-CLOSE-REQ.DU',
    'UE-RESET-INDICATION.UE',
    'UE-RELEASE-INDICATION',
    'UE-INFO-UPDATE-INDICATION',
    'DSC-PMCTRL-DRB-SETUP-SUCCESS',
    'DSC-PMCTRL-DRB-RELEASE',
    'DSC-PMCTRL-NG-HANDOVER-EXECUTION-SUCCESS',
    'DSC-PMCTRL-NG-HANDOVER-EXECUTION-FAILURE'
]

# Filter dRAX Events and log them
for drax_event in drax_events:
    if drax_event in data['topic']:
        logging.info("Received [{drax_event}] dRAX RAN Event: {data}".format(
                drax_event=drax_event,
                data=data
        ))

1.2 dRAX RAN Events Messages¶

1.2.1 F1-SEIZE-REQUEST¶

Topic: F1-SEIZE-REQUEST

Description: Sent when a DU connects to the CU over F1-C

Fields of interest: - AssocId: ID of the connection - SenderIp: IP of the DU

1.2.2 F1-SCTP-ASSOC-FAILURE-IND.DU¶

Topic: F1-SCTP-ASSOC-FAILURE-IND.DU

Description: Sent when a DU disconnects from the CU on F1-C

Fields of interest: - AssocId: ID of the connection

1.2.3 F1-ASSOC-CLOSE-REQ.DU¶

Topic: F1-ASSOC-CLOSE-REQ.DU

Description: Sent when the CU closes the F1-C connection to a DU

Fields of interest: - AssocId: ID of the connection

1.2.4 UE-RESET-INDICATION.UE¶

Topic: UE-RESET-INDICATION.UE

Description: Sent when the CU resets a UE for various reasons

Fields of interest: - GnbCuCpUeId: The CU-CP-ID of the UE

1.2.5 UE-RELEASE-INDICATION¶

Topic: UE-RELEASE-INDICATION

Description: Sent when a UE is released for whatever reason

Fields of interest: - CuCpUeId: The CU-CP UE ID of the released UE - RanUeId: The RAN UE ID of the released UE (if known)

1.2.6 UE-INFO-UPDATE-INDICATION¶

Topic: UE-INFO-UPDATE-INDICATION

Description: Sent when a UE connects or any of its attributes change

Fields of interest: - CuCpUeId - RanUeId - DuUeId - CRnti - AmfUeId - Tmsi - Guami - NrCgi

1.2.7 DSC-PMCTRL-DRB-SETUP-SUCCESS¶

Topic: DSC-PMCTRL-DRB-SETUP-SUCCESS

Description: A DRB was successfully set up

Fields of interest: - FiveQI: The 5QI associated with the DRB - SNssai: The S-NSSAI associated with the DRB

1.2.8 DSC-PMCTRL-DRB-RELEASE¶

Topic: DSC-PMCTRL-DRB-RELEASE

Description: A DRB was released

Fields of interest: - FiveQI: The 5QI associated with the DRB - SNssai: The S-NSSAI associated with the DRB

1.2.9 DSC-PMCTRL-NG-HANDOVER-EXECUTION-SUCCESS¶

Topic: DSC-PMCTRL-NG-HANDOVER-EXECUTION-SUCCESS

Description: An NGAP HO was successfully executed

Fields of interest: - NrCgi: The NR-CGI of the source cell

1.2.10 DSC-PMCTRL-NG-HANDOVER-EXECUTION-FAILURE¶

Topic: DSC-PMCTRL-NG-HANDOVER-EXECUTION-FAILURE

Description: An NGAP HO has failed