Diameter Rf Interface¶

Overview¶

The Diameter Rf interface is used for offline charging in IP Multimedia Subsystem (IMS) networks. It supports the transfer of charging information between network elements and the Charging Data Function (CDF).

Interface Specifications¶

Rf Interface (3GPP TS 32.299)¶

Application ID: 3 (Accounting)
Vendor ID: 10415 (3GPP)
Commands:
Accounting-Request (ACR)
Accounting-Answer (ACA)
Record Types:
START
INTERIM
STOP
EVENT

Message Flows¶

Basic Accounting Flow¶

sequenceDiagram
    participant CTF as Charging Trigger Function
    participant CDF as Charging Data Function

    CTF->>CDF: ACR[Start]
    CDF->>CTF: ACA[Start]
    Note over CTF,CDF: Service Delivery
    CTF->>CDF: ACR[Interim]
    CDF->>CTF: ACA[Interim]
    Note over CTF,CDF: Service Continues
    CTF->>CDF: ACR[Stop]
    CDF->>CTF: ACA[Stop]

Implementation Examples¶

Session Start Record¶

from telcoapi.diameter import rf

# Initialize Rf client
client = rf.RfClient(
    host="client.example.com",
    realm="example.com",
    destination_host="cdf.example.com",
    destination_realm="example.com"
)

# Send start record
acr_start = client.create_acr(
    session_id="session123",
    accounting_record_type="START",
    subscription_id="123456789",
    service_information={
        "ims_information": {
            "node_functionality": "S-CSCF",
            "role_of_node": ["ORIGINATING"]
        }
    }
)

response = client.send_acr(acr_start)
print(f"Start record response: {response}")

Interim Record¶

# Send interim record
acr_interim = client.create_acr(
    session_id="session123",
    accounting_record_type="INTERIM",
    subscription_id="123456789",
    service_information={
        "ims_information": {
            "node_functionality": "S-CSCF",
            "role_of_node": ["ORIGINATING"],
            "inter_operator_identifier": [{
                "originating_ioi": "operator-a.com",
                "terminating_ioi": "operator-b.com"
            }]
        }
    }
)

response = client.send_acr(acr_interim)

Stop Record¶

# Send stop record
acr_stop = client.create_acr(
    session_id="session123",
    accounting_record_type="STOP",
    subscription_id="123456789",
    service_information={
        "ims_information": {
            "node_functionality": "S-CSCF",
            "role_of_node": ["ORIGINATING"],
            "cause_code": 200,
            "session_priority": "NORMAL"
        },
        "time_stamps": {
            "sip_request_timestamp": "2024-02-20T10:00:00Z",
            "sip_response_timestamp": "2024-02-20T10:01:30Z"
        }
    }
)

response = client.send_acr(acr_stop)

Vendor Integration¶

Huawei CDF Integration¶

# Huawei CDF configuration
client.set_vendor_config({
    "vendor_id": 2011,  # Huawei vendor ID
    "product_name": "Huawei CDF",
    "firmware_revision": 1,
    "custom_avps": [
        {"code": 7001, "name": "Huawei-Charging-Node"},
        {"code": 7002, "name": "Huawei-Session-Priority"}
    ]
})

Oracle CDF Integration¶

# Oracle configuration
client.set_vendor_config({
    "vendor_id": 111,   # Oracle vendor ID
    "product_name": "Oracle CDF",
    "firmware_revision": 1,
    "custom_avps": [
        {"code": 6001, "name": "Oracle-Service-Context"},
        {"code": 6002, "name": "Oracle-Record-Priority"}
    ]
})

Error Handling¶

Common Error Scenarios¶

Result Code	Name	Description	Action
5001	USER_UNKNOWN	Unknown user	Verify user identity
5002	DIAMETER_UNABLE_TO_DELIVER	Delivery failed	Check connectivity
5003	DIAMETER_TOO_BUSY	System overloaded	Implement backoff
5004	DIAMETER_LOOP_DETECTED	Routing loop	Check configuration

Error Handling Example¶

from telcoapi.diameter.exceptions import AccountingError

try:
    response = client.send_acr(acr_request)
except AccountingError as e:
    if e.result_code == 5003:  # TOO_BUSY
        # Implement exponential backoff
        retry_with_backoff(e.request)
    else:
        # Log error and take appropriate action
        logger.error(f"Accounting error: {e}")

Monitoring¶

Key Metrics¶

Record Delivery Success Rate
Average Response Time
Record Generation Rate
File Creation Time
CDR Processing Rate

Monitoring Example¶

# Register monitoring callbacks
@client.on_metrics
def collect_accounting_metrics(metrics):
    print(f"Record delivery success rate: {metrics.success_rate}%")
    print(f"Average response time: {metrics.avg_response_time}ms")
    print(f"Records per second: {metrics.records_per_second}")

Configuration Examples¶

Basic Configuration¶

rf_interface:
  host: "client.example.com"
  realm: "example.com"
  port: 3868
  application_id: 3
  vendor_id: 10415
  security:
    tls_enabled: true
    certificate: "/path/to/cert.pem"
    private_key: "/path/to/key.pem"
  peers:
    - host: "cdf1.example.com"
      realm: "example.com"
      port: 3868
      role: "server"
    - host: "cdf2.example.com"
      realm: "example.com"
      port: 3868
      role: "server"

Advanced Configuration¶

rf_interface:
  host: "client.example.com"
  realm: "example.com"
  port: 3868
  application_id: 3
  vendor_id: 10415
  vendor_specific:
    vendor_id: 2011
    product_name: "Example CDF Client"
    firmware_revision: 1
  security:
    tls_enabled: true
    certificate: "/path/to/cert.pem"
    private_key: "/path/to/key.pem"
    cipher_suites:
      - "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384"
      - "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256"
  routing:
    strategy: "round_robin"
    failover_enabled: true
    retry_count: 3
    timeout: 5000
  record_management:
    interim_interval: 300
    file_format: "ASN.1"
    file_rotation: 3600
    compression_enabled: true
  peers:
    - host: "cdf1.example.com"
      realm: "example.com"
      port: 3868
      role: "server"
      weight: 100
    - host: "cdf2.example.com"
      realm: "example.com"
      port: 3868
      role: "server"
      weight: 100

Best Practices¶

Implement reliable record delivery
Use appropriate interim intervals
Enable TLS for security
Implement proper failover
Monitor record delivery rates
Handle file rotation properly
Implement record correlation
Use appropriate timestamps
Handle multi-session scenarios
Implement proper CDR verification