Call Detail Records (CDRs)

Table of Contents

1. Overview & Accounting Architecture
2. Business & Operational Significance
3. 🎯 User Roles & Key Capabilities
4. Visual Interface & Layout
5. Field & Telemetry Reference
6. Kamailio Core Accounting Mechanics
7. Search, Filtering & CSV Export
8. Database Maintenance & High-Volume Partitioning
9. Troubleshooting & Verification
10. Model Context Protocol (MCP) AI Integration
11. Glossary

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1. Overview & Accounting Architecture

In Ring2All SBC, the Call Detail Records (CDRs) module provides carrier-grade session accounting, duration measurement, and termination analytics for all SIP traffic transiting the perimeter. Powered by Kamailio’s native dialog-aware accounting engine (acc module configured with cdr_enable), the SBC automatically correlates session establishment (INVITE / 200 OK) and session teardown (BYE / CANCEL), computing exact billable durations and associating real-time media quality metrics.

External Carrier / PBX              Ring2All SBC (Kamailio Core)               PostgreSQL Storage
         │                                       │                                     │
         │─────── SIP INVITE (Initial) ─────────>│                                     │
         │<────── 100 Trying / 180 Ringing ──────│                                     │
         │<────── 200 OK (Call Answered) ────────│─── Create Dialog Context ──────────>│
         │                                       │    Record start_time & src_ip       │
         │═══════ Active RTP Audio Media ════════│                                     │
         │                                       │                                     │
         │─────── SIP BYE (Call Terminated) ────>│                                     │
         │<────── 200 OK (Teardown Ack) ─────────│─── Calculate Duration ─────────────>│
         │                                       │    Attach RTPEngine MOS/Jitter      │
         │                                       │    INSERT INTO acc_cdrs ────────────>│

Unlike basic SIP proxy loggers that produce disjointed message rows, Ring2All SBC provides:

1. Consolidated Session Records: Each row represents a complete end-to-end telephone call with unified start time, end time, and duration.
2. Dual-Perspective Tracking: Dedicated accounting views for successfully answered sessions (acc_cdrs) versus early rejects, timeouts, and uncompleted calls (missed_calls).
3. Integrated Voice Quality Forensics: Continuous Mean Opinion Score (MOS), network jitter, and packet loss measurements captured directly from RTPEngine media relays.

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2. Business & Operational Significance

• Carrier Interconnect Settlement: Supplies indisputable, microsecond-accurate session records required for carrier billing reconciliation, dispute defense, and LCR cost auditing.
• Service Level Agreement (SLA) Verification: Empowers Network Operations Center (NOC) teams to track answer-seizure ratios (ASR), average call durations (ACD), and post-dial delay across specific SIP trunks and domains.
• Rapid Fault Isolation: Differentiates between normal subscriber hang-ups (200 OK / 487 Request Terminated) and upstream provider outages (503 Service Unavailable, 404 Not Found, 486 Busy Here).
• Compliance & Legal Auditing: Maintains an immutable evidentiary trail of all caller identities, dialed digits, source IP addresses, and routing destinations in accordance with telecom data retention regulations.

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3. 🎯 User Roles & Key Capabilities

Role	Primary Use Case	Key Capabilities
Carrier NOC Engineer	Live Traffic Monitoring & Incident Triage	Track real-time call volume, investigate sudden spikes in failed or rejected calls, and verify trunk interconnect stability.
Interconnect Billing Analyst	Inter-Carrier Settlement & Reconciliation	Export filtered CDR streams in CSV format, audit billable duration aggregates, and verify per-minute cost attribution.
SBC Administrator	System Health & Retention Governance	Configure PostgreSQL database retention policies, optimize accounting indexes, and verify Kamailio database flushing queues.
Compliance Auditor	Regulatory Verification	Inspect historical call records, verify caller ID integrity, and generate time-bounded telecom access reports.
AI Platform Copilot / NOC Diagnostic Agent	Autonomous CDR Triage & Anomaly Detection	Inspect high-failure CDR bursts, analyze SIP response codes (503/486/404), evaluate ASR/ACD trends, and pinpoint carrier interconnect degradations.

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4. Visual Interface & Layout

The CDR interface is structured with executive KPI telemetry cards at the top, a dual-tab navigation selector (CDR vs Missed Calls), an advanced filtering bar, and a high-density DataGrid.

4.1 Completed Call Detail Records View

The primary CDR tab displays all successfully established and answered sessions with duration, SIP termination code, ingress domain, and voice quality metrics.

4.2 Missed & Unanswered Calls View

The Missed Calls tab captures all call attempts that terminated prior to an answer (e.g., caller cancellation, busy subscriber, route unreachability, or authentication failures).

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5. Field & Telemetry Reference

Executive Summary Cards

Card Metric	Calculation / Origin	Operational Meaning
Total Calls	Total count of recorded sessions in selected scope	Aggregate traffic volume across the entire SBC cluster.
Calls Today	Count of sessions initiated since midnight local time	Daily volume tracking for capacity planning and peak load monitoring.
Average Duration	Sum of billable seconds divided by answered calls	Reflects typical customer call length (ACD). Sudden drops indicate routing anomalies.
Answered	Percentage of calls terminating with 200 OK	Answer-Seizure Ratio (ASR). Healthy enterprise traffic typically benchmarks above 70%.
Failed	Percentage of calls resulting in 4xx, 5xx, or 6xx errors	Immediate indicator of carrier trunk congestion, destination misconfigurations, or network dropouts.

CDR DataGrid Columns

Column	Data Type	Source	Description
Result	Badge	acc_cdrs.sip_code	Color-coded SIP final response code (200 Green, 486 Amber, 487 Gray, 404/503 Red).
From URI	String	acc_cdrs.from_uri	Originating caller identity and display name (e.g., sip:2000@192.168.11.130:5060).
To URI	String	acc_cdrs.to_uri	Dialed destination number or target extension (e.g., sip:mod_sofia@192.168.10.31:5080).
Domain	String	acc_cdrs.domain	Ingress or tenant SIP domain associated with the session.
Duration	Formatted	acc_cdrs.duration	Total billable conversational duration formatted as minutes and seconds (e.g., 45s, 3m 12s).
MOS	Float	RTPEngine RTCP XR	Estimated Mean Opinion Score for voice quality (scale 1.0 to 5.0).
Jitter	Milliseconds	RTPEngine RTCP XR	Average inter-arrival packet variation measured across the audio stream.
Loss	Percentage	RTPEngine RTCP XR	Cumulative audio packet loss percentage throughout the session.
Source IP	IPv4 / IPv6	acc_cdrs.src_ip	Remote IP address of the signaling endpoint or carrier trunk initiating the request.
Start Time	Timestamp	acc_cdrs.start_time	UTC timestamp when the initial INVITE was processed by the SBC.

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6. Kamailio Core Accounting Mechanics

Ring2All SBC utilizes Kamailio’s acc module linked with the dialog module. Rather than writing individual transaction records to disk, Kamailio maintains stateful dialog structures in memory and writes CDR rows upon receipt of teardown signaling:

# Kamailio acc module configuration snippet
loadmodule "acc.so"
modparam("acc", "db_url", "postgres://kamailio:SECRET@localhost/kamailio")
modparam("acc", "cdr_enable", 1)
modparam("acc", "cdrs_table", "acc_cdrs")
modparam("acc", "failed_transaction_flag", 3)
modparam("acc", "cdr_start_on_confirmed", 1)
modparam("acc", "cdr_extra", "from_uri=$fu;to_uri=$ru;src_ip=$si;domain=$rd")

Dialog Lifecycle Stages

1. Dialog Creation: Triggered upon receipt of valid INVITE. Kamailio allocates a memory tracking block keyed by Call-ID, From-tag, and To-tag.
2. Confirmation: Upon receiving 200 OK, cdr_start_on_confirmed records the microsecond answer timestamp.
3. Termination: When BYE passes through the SBC, Kamailio calculates duration = end_time - start_time, flushes the accumulated extra variables, and dispatches an asynchronous SQL insert to PostgreSQL.
4. Early Termination (Missed Calls): If the dialog terminates before 200 OK (e.g., CANCEL, 486 Busy, or 404 Not Found), Kamailio routes the event into the missed_calls table with the exact sip_code and sip_reason.

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7. Search, Filtering & CSV Export

The CDR interface incorporates carrier-grade filtering controls to quickly isolate specific sessions across millions of database rows:

• Date Range Picker: Quick presets for Today, Yesterday, Last 7 Days, Last 30 Days, or custom calendar time-bounds.
• SIP Domain Filter: Multi-tenant selector allowing operators to isolate traffic for a specific enterprise client or PBX cluster.
• Full-Text Search Engine: Real-time matching against Call-ID, caller phone numbers, dialed digits, or IP addresses.
• CSV Streaming Export: Clicking the Export button invokes /api/cdrs/export, streaming zipped or plaintext CSV datasets directly from PostgreSQL without exhausting web application memory.

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8. Database Maintenance & High-Volume Partitioning

In high-throughput environments processing millions of minutes per month, standard single-table storage will degrade query performance. Ring2All SBC leverages native PostgreSQL 17 table partitioning:

-- PostgreSQL 17 Table Partitioning Strategy
CREATE TABLE acc_cdrs (
    id BIGSERIAL,
    call_id VARCHAR(255) NOT NULL,
    from_uri VARCHAR(255) NOT NULL,
    to_uri VARCHAR(255) NOT NULL,
    start_time TIMESTAMP WITH TIME ZONE NOT NULL,
    end_time TIMESTAMP WITH TIME ZONE,
    duration INTEGER DEFAULT 0,
    sip_code VARCHAR(10),
    src_ip INET,
    domain VARCHAR(128),
    mos NUMERIC(3,2),
    jitter NUMERIC(5,2),
    packet_loss NUMERIC(5,2),
    PRIMARY KEY (id, start_time)
) PARTITION BY RANGE (start_time);

-- Example Monthly Partition
CREATE TABLE acc_cdrs_2026_09 PARTITION OF acc_cdrs
    FOR VALUES FROM ('2026-09-01 00:00:00+00') TO ('2026-10-01 00:00:00+00');

CREATE INDEX idx_cdrs_start_time ON acc_cdrs_2026_09 (start_time DESC);
CREATE INDEX idx_cdrs_call_id ON acc_cdrs_2026_09 (call_id);
CREATE INDEX idx_cdrs_domain ON acc_cdrs_2026_09 (domain);

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9. Troubleshooting & Verification

Inspecting Live Accounting Tables via CLI

Verify that Kamailio is actively writing records to PostgreSQL:

# Connect to SBC Kamailio database
psql -U kamailio -d kamailio -c "
SELECT id, start_time, duration, sip_code, from_uri, to_uri
FROM acc_cdrs
ORDER BY id DESC LIMIT 5;"

Checking Dialog Module Memory

Ensure active dialogs are tracking properly in Kamailio memory:

# Query active dialog count via kamcmd
kamcmd dlg.profile_get_size global

Verifying Failed / Missed Calls

Investigate the most frequent failure causes over the last hour:

psql -U kamailio -d kamailio -c "
SELECT sip_code, sip_reason, count(*)
FROM missed_calls
WHERE time > NOW() - INTERVAL '1 hour'
GROUP BY sip_code, sip_reason
ORDER BY count DESC;"

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10. Model Context Protocol (MCP) AI Integration

The Call Detail Records (CDRs) subsystem is natively integrated with the Ring2All SBC Model Context Protocol (MCP) server. Autonomous AI agents, NOC triage copilots, and billing reconciliation models use the following tools to inspect traffic patterns, investigate failed call bursts, and audit carrier interconnect volume.

Available MCP Tools

Tool Name	Operation Type	Risk Level	Description
get_sbc_cdrs	Read / Forensic Query	read	Query and filter recent CDRs passing through the SBC by telephone number, SIP response code, direction, or Call-ID.
get_traffic_analytics	Aggregate Analytics	read	Retrieve aggregated SIP traffic volume, ASR percentage, ACD duration, and SIP code distribution over a specified time window.
get_top_destinations	Aggregated Telemetry	read	Retrieve the highest-volume dialed destination numbers and prefix groups with attempt counts and completion rates.

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Tool Schemas & Payloads

1. get_sbc_cdrs

Input Schema

{
  "type": "object",
  "properties": {
    "search": {
      "type": "string",
      "description": "Filter by phone number, URI, or Call-ID string."
    },
    "direction": {
      "type": "string",
      "enum": ["inbound", "outbound"],
      "description": "Filter by session direction relative to the perimeter."
    },
    "sipCode": {
      "type": "string",
      "description": "Filter by SIP final status code (e.g. '200', '486', '503', '404')."
    },
    "limit": {
      "type": "number",
      "description": "Number of records to return (default: 20, max: 100)."
    }
  }
}

Output Payload Example

{
  "success": true,
  "count": 2,
  "cdrs": [
    {
      "id": "184029",
      "call_id": "4d90a1-89e4-41bf-a81b-789a65c2e912@sbc.carrier.net",
      "from_uri": "sip:+17865550199@192.168.11.130:5060",
      "to_uri": "sip:+18005550100@sbc.ring2all.com:5060",
      "start_time": "2026-09-08T15:20:11.182Z",
      "end_time": "2026-09-08T15:24:26.419Z",
      "duration_seconds": 255,
      "sip_code": "200",
      "sip_reason": "OK",
      "direction": "inbound",
      "mos": 4.38,
      "jitter_ms": 12.4,
      "packet_loss_pct": 0.0,
      "source_ip": "192.168.11.130",
      "destination_ip": "192.168.10.31"
    },
    {
      "id": "184030",
      "call_id": "c88f12-0012-4cf3-94df-66b93e8172da@gw01.telco.net",
      "from_uri": "sip:+13055550144@192.168.11.140:5060",
      "to_uri": "sip:+18885559988@sbc.ring2all.com:5060",
      "start_time": "2026-09-08T15:22:04.090Z",
      "end_time": "2026-09-08T15:22:05.110Z",
      "duration_seconds": 0,
      "sip_code": "503",
      "sip_reason": "Service Unavailable",
      "direction": "outbound",
      "mos": null,
      "jitter_ms": null,
      "packet_loss_pct": null,
      "source_ip": "192.168.10.31",
      "destination_ip": "203.0.113.50"
    }
  ]
}

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2. get_traffic_analytics

Input Schema

{
  "type": "object",
  "properties": {
    "period": {
      "type": "string",
      "enum": ["1h", "6h", "24h", "7d"],
      "description": "Time window for analytics calculation (default: '24h')."
    }
  }
}

Output Payload Example

{
  "period": "24h",
  "total_attempts": 28490,
  "answered_calls": 21940,
  "failed_calls": 6550,
  "asr_pct": 77.01,
  "acd_seconds": 184,
  "sip_distribution": {
    "200_OK": 21940,
    "486_Busy_Here": 2410,
    "487_Request_Terminated": 2890,
    "404_Not_Found": 840,
    "503_Service_Unavailable": 410
  },
  "peak_cps": 34.2,
  "average_mos": 4.31
}

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3. get_top_destinations

Input Schema

{
  "type": "object",
  "properties": {
    "limit": {
      "type": "number",
      "description": "Number of top destinations to return (default: 10, max: 50)."
    }
  }
}

Output Payload Example

{
  "top_destinations": [
    {
      "destination_prefix": "+1800",
      "country": "United States (Toll-Free)",
      "total_calls": 8450,
      "answered": 7120,
      "asr_pct": 84.26,
      "total_duration_minutes": 26890
    },
    {
      "destination_prefix": "+1305",
      "country": "United States (Florida)",
      "total_calls": 4210,
      "answered": 3180,
      "asr_pct": 75.53,
      "total_duration_minutes": 9840
    }
  ]
}

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Natural Language AI Prompts

English Examples

• “Show me the last 15 failed calls with SIP code 503 that occurred in the past hour.”
• “Analyze our traffic volume over the last 24 hours and report the current ASR and average call duration.”
• “Which destination prefixes are generating the highest volume of calls and what is their completion rate?”

Spanish Examples (Español)

• “Muéstrame las últimas 15 llamadas fallidas con código SIP 503 ocurridas en la última hora.”
• “Analiza el volumen de tráfico de las últimas 24 horas e infórmame el ASR actual y la duración promedio de llamada.”
• “¿Cuáles son los prefijos de destino con mayor volumen de tráfico y cuál es su tasa de completamiento?”

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Enterprise Safeguards & Access Governance

1. Read-Only Telemetry Queries: CDR analytic tools strictly query relational accounting partitions (acc_cdrs, missed_calls) using bounded LIMIT and indexed start_time ranges. No SQL mutations or table locks are issued.
2. Strict Limit Enforcement: The limit parameter is clamped to a maximum of 100 records per tool invocation to prevent memory exhaustion in Fastify and Kamailio pools.
3. Role-Based Execution Isolation: Tools are governed by MCP Role Profiles. Only roles containing cdr_analytics permissions (such as noc_network_engineer, lcr_carrier_manager, and security_auditor) can invoke CDR inspection tools.

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11. Glossary

• ACD (Average Call Duration): Statistical benchmark measuring the average length of answered telephone conversations.
• ASR (Answer-Seizure Ratio): Percentage of call attempts that result in a successful 200 OK answer state.
• Call-ID: Globally unique string identifier generated by SIP endpoints to distinguish a specific dialog.
• Dialog: A peer-to-peer SIP relationship between two user agents that persists for the lifetime of a session.
• RTCP XR (Extended Reports): Protocol standard for exchanging voice quality telemetry (MOS, jitter, packet loss) between RTP endpoints.