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1. CCC Subscription Response

1.1 CccXappSubscriptionResponsePublisherPubData

The CccXappSubscriptionResponsePublisherPubData defines the structure of the response to a CCC (Cell Configuration and Control) subscription request between the E2 nodes and the RAN Intelligent Controller (RIC) over the E2 interface.

This response message informs the RIC whether the subscription request for monitoring cell configurations was successfully processed by the E2 node.

It includes details such as whether the subscription setup was successful or if any errors occurred during the process.

1.2 Examples

Info

To receive a CCC Subscription response, the following NATS subject must be used:

e2-t.E2SM-CCC-SUBSCRIPTION-RESP
This subject is responsible for sending the CCC subscription message.

The following Python example demonstrates how to receive a CCC subscription response.

Example

Receive CCC Subscription Response example:

# Add Accelleran xapp library
from xapp_lib import xapp_lib
# Add protobuf definitions
from xapp_lib.proto_pb2.accelleran.e2 import genXappCcc_pb2
# Add function to serialize json dict in protobuf
from google.protobuf.json_format import ParseDict

def e2sm_ccc_subscription_resp(encoded_data):
    data = genXappCcc_pb2.CccXappSubscriptionResponsePublisherPubData()
    data.ParseFromString(encoded_data)
    return data.E2smBaseSubscriptionResponseData

msgList = [
    ("E2SM-CCC-SUBSCRIPTION-RESP", e2sm_ccc_subscription_resp),
]

def get_subject_list(req_id, ins_id):
    subjects = []
    for msg in msgList:
        subjects.append(
            "e2-t."
            + msg[0]
            + ".RIC_REQUESTOR="
            + str(req_id)
            + ".RIC_INSTANCE="
            + str(ins_id)
        )
    return subjects

def decoder(subject, encoded_data):
    item = [item for item in msgList if item[0] == subject and item[1] != None]
    if not item:
        logging.error(f"Subject not supported: {subject}. Cannot decode the message.")
        return None
    return dict(item)[subject](encoded_data)

def extract_subject(input_string):
    components = input_string.split(".")
    for component in components:
        for subject, _ in msgList:
            if subject in component:
                return subject
    return None

def main():

    ### Use xApp Builder to create the xApp
    builder = xapp_lib.XAppBuilder("../..", absolute=False)
    builder.metadata("core/xapp_metadata.json")
    builder.endpoints("config/xapp_endpoints.json")
    builder.config("config/xapp_config.json")
    builder.readme("README.md")
    xapp = builder.build()

    # Get xApp request id
    req_id = xapp.id
    # Get xApp instance id
    node_a_ins_id = xapp.transaction_id_gen.get()

    # Listen for E2 Subscription responses
    e2_node_a_subjects = get_subject_list(req_id, node_a_ins_id)
    xapp.nats(endpoint="NATS_URL_5G").subscribe(e2_node_a_subjects)

    # Reception of E2 subscription response
    for _ in range(10):
        data = xapp.nats().recv_data()
        subject = extract_subject(data[0])
        decoded_resp = decoder(subject, data[1])
        logging.info("Received message: {data}".format(data=decoded_resp))

1.3 Schema

This section provides the JSON schema for the E2 CCC Subscription Response, which outlines the expected structure and data types.

E2 CCC Subscription Response schema
{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "$ref": "#/definitions/CccXappSubscriptionResponsePublisherPubData",
    "definitions": {
        "CccXappSubscriptionResponsePublisherPubData": {
            "properties": {
                "E2smBaseSubscriptionResponseData": {
                    "$ref": "#/definitions/PBE2apMsgData.E2smBaseSubscriptionResponseData",
                    "additionalProperties": true,
                    "description": "See E2smBaseSubscriptionResponseData for detailed description of this field"
                },
                "tlpublishTime": {
                    "type": "string",
                    "description": "Contains the time of publishing in EPOCH milliseconds"
                },
                "spanContext": {
                    "type": "string",
                    "description": "Contains an opentracing spancontext",
                    "format": "binary",
                    "binaryEncoding": "base64"
                }
            },
            "additionalProperties": true,
            "type": "object",
            "title": "Ccc Xapp Subscription Response Publisher Pub Data",
            "description": "* Publisher : CccXappSubscriptionResponsePublisher Topic : E2SM-CCC-SUBSCRIPTION-RESP.RIC_REQUESTOR=*.RIC_INSTANCE=* Description : Publishes the E2 subscription response received from the E2 Termination node to the xAPP"
        },
        "PBE2apMsgData.E2smBaseSubscriptionResponseData": {
            "properties": {
                "RequestId": {
                    "$ref": "#/definitions/PBE2apMsgData.RicRequestId",
                    "additionalProperties": true
                },
                "RanFunctionName": {
                    "type": "string"
                },
                "RanFunctionId": {
                    "type": "integer"
                },
                "RcNodeId": {
                    "$ref": "#/definitions/PBE2apMsgData.GlobalE2NodeId",
                    "additionalProperties": true
                },
                "RicActionsAdmitted": {
                    "$ref": "#/definitions/PBE2apMsgData.RicActionIdList",
                    "additionalProperties": true
                }
            },
            "additionalProperties": true,
            "type": "object",
            "title": "E 2 Sm Base Subscription Response Data"
        },
        "PBE2apMsgData.GlobalE2NodeId": {
            "properties": {
                "GlobalGnbId": {
                    "$ref": "#/definitions/PBE2apMsgData.GlobalGnbId",
                    "additionalProperties": true
                },
                "OptionalGnbCuUpId": {
                    "type": "string"
                },
                "OptionalGnbDuId": {
                    "type": "string"
                }
            },
            "additionalProperties": true,
            "type": "object",
            "title": "Global E 2 Node Id",
            "description": "*O-RAN.WG3.E2AP-v02.00 9.2.6 Global E2 Node ID"
        },
        "PBE2apMsgData.GlobalGnbId": {
            "properties": {
                "PlmnIdentity": {
                    "$ref": "#/definitions/PBE2apMsgData.PlmnIdentity",
                    "additionalProperties": true
                },
                "GnbId": {
                    "$ref": "#/definitions/PBE2apMsgData.GnbId",
                    "additionalProperties": true
                }
            },
            "additionalProperties": true,
            "type": "object",
            "title": "Global Gnb Id"
        },
        "PBE2apMsgData.GnbId": {
            "properties": {
                "Value": {
                    "type": "integer"
                },
                "Length": {
                    "type": "integer",
                    "description": "Number of bits used in the gnbId. This may vary from 22 to 32"
                }
            },
            "additionalProperties": true,
            "type": "object",
            "title": "Gnb Id"
        },
        "PBE2apMsgData.PlmnIdentity": {
            "properties": {
                "Data": {
                    "items": {
                        "type": "integer"
                    },
                    "type": "array"
                }
            },
            "additionalProperties": true,
            "type": "object",
            "title": "Plmn Identity",
            "description": "*O-RAN.WG3.E2SM-R003-v03.00 6.2.3.1 PLMN Identity"
        },
        "PBE2apMsgData.RicActionIdList": {
            "properties": {
                "items": {
                    "items": {
                        "type": "integer"
                    },
                    "type": "array",
                    "description": "Carries max MAX_OF_RIC_ACTION_ID elements of type uint32"
                }
            },
            "additionalProperties": true,
            "type": "object",
            "title": "Ric Action Id List"
        },
        "PBE2apMsgData.RicRequestId": {
            "properties": {
                "RicRequestorId": {
                    "type": "integer"
                },
                "RicInstanceId": {
                    "type": "integer"
                }
            },
            "additionalProperties": true,
            "type": "object",
            "title": "Ric Request Id"
        }
    }
}